From e0d0bf8a28eb04efd997478ef3d82319cdef9455 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 25 Apr 2020 18:19:30 -0400
Subject: [PATCH 01/10] comedi: move compat ioctl handling to native fops

mechanical move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/staging/comedi/Makefile          |   1 -
 drivers/staging/comedi/comedi_compat32.c | 455 -----------------------
 drivers/staging/comedi/comedi_compat32.h |  28 --
 drivers/staging/comedi/comedi_fops.c     | 451 +++++++++++++++++++++-
 4 files changed, 448 insertions(+), 487 deletions(-)
 delete mode 100644 drivers/staging/comedi/comedi_compat32.c
 delete mode 100644 drivers/staging/comedi/comedi_compat32.h

diff --git a/drivers/staging/comedi/Makefile b/drivers/staging/comedi/Makefile
index 6af5da3b4315..072ed83a5a6a 100644
--- a/drivers/staging/comedi/Makefile
+++ b/drivers/staging/comedi/Makefile
@@ -4,7 +4,6 @@ ccflags-$(CONFIG_COMEDI_DEBUG)		:= -DDEBUG
 comedi-y				:= comedi_fops.o range.o drivers.o \
 					   comedi_buf.o
 comedi-$(CONFIG_PROC_FS)		+= proc.o
-comedi-$(CONFIG_COMPAT)			+= comedi_compat32.o
 
 obj-$(CONFIG_COMEDI_PCI_DRIVERS)	+= comedi_pci.o
 obj-$(CONFIG_COMEDI_PCMCIA_DRIVERS)	+= comedi_pcmcia.o
diff --git a/drivers/staging/comedi/comedi_compat32.c b/drivers/staging/comedi/comedi_compat32.c
deleted file mode 100644
index 36a3564ba1fb..000000000000
--- a/drivers/staging/comedi/comedi_compat32.c
+++ /dev/null
@@ -1,455 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- * comedi/comedi_compat32.c
- * 32-bit ioctl compatibility for 64-bit comedi kernel module.
- *
- * Author: Ian Abbott, MEV Ltd. <abbotti@mev.co.uk>
- * Copyright (C) 2007 MEV Ltd. <http://www.mev.co.uk/>
- *
- * COMEDI - Linux Control and Measurement Device Interface
- * Copyright (C) 1997-2007 David A. Schleef <ds@schleef.org>
- */
-
-#include <linux/uaccess.h>
-#include <linux/compat.h>
-#include <linux/fs.h>
-#include "comedi.h"
-#include "comedi_compat32.h"
-
-#define COMEDI32_CHANINFO _IOR(CIO, 3, struct comedi32_chaninfo_struct)
-#define COMEDI32_RANGEINFO _IOR(CIO, 8, struct comedi32_rangeinfo_struct)
-/*
- * N.B. COMEDI32_CMD and COMEDI_CMD ought to use _IOWR, not _IOR.
- * It's too late to change it now, but it only affects the command number.
- */
-#define COMEDI32_CMD _IOR(CIO, 9, struct comedi32_cmd_struct)
-/*
- * N.B. COMEDI32_CMDTEST and COMEDI_CMDTEST ought to use _IOWR, not _IOR.
- * It's too late to change it now, but it only affects the command number.
- */
-#define COMEDI32_CMDTEST _IOR(CIO, 10, struct comedi32_cmd_struct)
-#define COMEDI32_INSNLIST _IOR(CIO, 11, struct comedi32_insnlist_struct)
-#define COMEDI32_INSN _IOR(CIO, 12, struct comedi32_insn_struct)
-
-struct comedi32_chaninfo_struct {
-	unsigned int subdev;
-	compat_uptr_t maxdata_list;	/* 32-bit 'unsigned int *' */
-	compat_uptr_t flaglist;	/* 32-bit 'unsigned int *' */
-	compat_uptr_t rangelist;	/* 32-bit 'unsigned int *' */
-	unsigned int unused[4];
-};
-
-struct comedi32_rangeinfo_struct {
-	unsigned int range_type;
-	compat_uptr_t range_ptr;	/* 32-bit 'void *' */
-};
-
-struct comedi32_cmd_struct {
-	unsigned int subdev;
-	unsigned int flags;
-	unsigned int start_src;
-	unsigned int start_arg;
-	unsigned int scan_begin_src;
-	unsigned int scan_begin_arg;
-	unsigned int convert_src;
-	unsigned int convert_arg;
-	unsigned int scan_end_src;
-	unsigned int scan_end_arg;
-	unsigned int stop_src;
-	unsigned int stop_arg;
-	compat_uptr_t chanlist;	/* 32-bit 'unsigned int *' */
-	unsigned int chanlist_len;
-	compat_uptr_t data;	/* 32-bit 'short *' */
-	unsigned int data_len;
-};
-
-struct comedi32_insn_struct {
-	unsigned int insn;
-	unsigned int n;
-	compat_uptr_t data;	/* 32-bit 'unsigned int *' */
-	unsigned int subdev;
-	unsigned int chanspec;
-	unsigned int unused[3];
-};
-
-struct comedi32_insnlist_struct {
-	unsigned int n_insns;
-	compat_uptr_t insns;	/* 32-bit 'struct comedi_insn *' */
-};
-
-/* Handle translated ioctl. */
-static int translated_ioctl(struct file *file, unsigned int cmd,
-			    unsigned long arg)
-{
-	if (file->f_op->unlocked_ioctl)
-		return file->f_op->unlocked_ioctl(file, cmd, arg);
-
-	return -ENOTTY;
-}
-
-/* Handle 32-bit COMEDI_CHANINFO ioctl. */
-static int compat_chaninfo(struct file *file, unsigned long arg)
-{
-	struct comedi_chaninfo __user *chaninfo;
-	struct comedi32_chaninfo_struct __user *chaninfo32;
-	int err;
-	union {
-		unsigned int uint;
-		compat_uptr_t uptr;
-	} temp;
-
-	chaninfo32 = compat_ptr(arg);
-	chaninfo = compat_alloc_user_space(sizeof(*chaninfo));
-
-	/* Copy chaninfo structure.  Ignore unused members. */
-	if (!access_ok(chaninfo32, sizeof(*chaninfo32)) ||
-	    !access_ok(chaninfo, sizeof(*chaninfo)))
-		return -EFAULT;
-
-	err = 0;
-	err |= __get_user(temp.uint, &chaninfo32->subdev);
-	err |= __put_user(temp.uint, &chaninfo->subdev);
-	err |= __get_user(temp.uptr, &chaninfo32->maxdata_list);
-	err |= __put_user(compat_ptr(temp.uptr), &chaninfo->maxdata_list);
-	err |= __get_user(temp.uptr, &chaninfo32->flaglist);
-	err |= __put_user(compat_ptr(temp.uptr), &chaninfo->flaglist);
-	err |= __get_user(temp.uptr, &chaninfo32->rangelist);
-	err |= __put_user(compat_ptr(temp.uptr), &chaninfo->rangelist);
-	if (err)
-		return -EFAULT;
-
-	return translated_ioctl(file, COMEDI_CHANINFO, (unsigned long)chaninfo);
-}
-
-/* Handle 32-bit COMEDI_RANGEINFO ioctl. */
-static int compat_rangeinfo(struct file *file, unsigned long arg)
-{
-	struct comedi_rangeinfo __user *rangeinfo;
-	struct comedi32_rangeinfo_struct __user *rangeinfo32;
-	int err;
-	union {
-		unsigned int uint;
-		compat_uptr_t uptr;
-	} temp;
-
-	rangeinfo32 = compat_ptr(arg);
-	rangeinfo = compat_alloc_user_space(sizeof(*rangeinfo));
-
-	/* Copy rangeinfo structure. */
-	if (!access_ok(rangeinfo32, sizeof(*rangeinfo32)) ||
-	    !access_ok(rangeinfo, sizeof(*rangeinfo)))
-		return -EFAULT;
-
-	err = 0;
-	err |= __get_user(temp.uint, &rangeinfo32->range_type);
-	err |= __put_user(temp.uint, &rangeinfo->range_type);
-	err |= __get_user(temp.uptr, &rangeinfo32->range_ptr);
-	err |= __put_user(compat_ptr(temp.uptr), &rangeinfo->range_ptr);
-	if (err)
-		return -EFAULT;
-
-	return translated_ioctl(file, COMEDI_RANGEINFO,
-				(unsigned long)rangeinfo);
-}
-
-/* Copy 32-bit cmd structure to native cmd structure. */
-static int get_compat_cmd(struct comedi_cmd __user *cmd,
-			  struct comedi32_cmd_struct __user *cmd32)
-{
-	int err;
-	union {
-		unsigned int uint;
-		compat_uptr_t uptr;
-	} temp;
-
-	/* Copy cmd structure. */
-	if (!access_ok(cmd32, sizeof(*cmd32)) ||
-	    !access_ok(cmd, sizeof(*cmd)))
-		return -EFAULT;
-
-	err = 0;
-	err |= __get_user(temp.uint, &cmd32->subdev);
-	err |= __put_user(temp.uint, &cmd->subdev);
-	err |= __get_user(temp.uint, &cmd32->flags);
-	err |= __put_user(temp.uint, &cmd->flags);
-	err |= __get_user(temp.uint, &cmd32->start_src);
-	err |= __put_user(temp.uint, &cmd->start_src);
-	err |= __get_user(temp.uint, &cmd32->start_arg);
-	err |= __put_user(temp.uint, &cmd->start_arg);
-	err |= __get_user(temp.uint, &cmd32->scan_begin_src);
-	err |= __put_user(temp.uint, &cmd->scan_begin_src);
-	err |= __get_user(temp.uint, &cmd32->scan_begin_arg);
-	err |= __put_user(temp.uint, &cmd->scan_begin_arg);
-	err |= __get_user(temp.uint, &cmd32->convert_src);
-	err |= __put_user(temp.uint, &cmd->convert_src);
-	err |= __get_user(temp.uint, &cmd32->convert_arg);
-	err |= __put_user(temp.uint, &cmd->convert_arg);
-	err |= __get_user(temp.uint, &cmd32->scan_end_src);
-	err |= __put_user(temp.uint, &cmd->scan_end_src);
-	err |= __get_user(temp.uint, &cmd32->scan_end_arg);
-	err |= __put_user(temp.uint, &cmd->scan_end_arg);
-	err |= __get_user(temp.uint, &cmd32->stop_src);
-	err |= __put_user(temp.uint, &cmd->stop_src);
-	err |= __get_user(temp.uint, &cmd32->stop_arg);
-	err |= __put_user(temp.uint, &cmd->stop_arg);
-	err |= __get_user(temp.uptr, &cmd32->chanlist);
-	err |= __put_user((unsigned int __force *)compat_ptr(temp.uptr),
-			  &cmd->chanlist);
-	err |= __get_user(temp.uint, &cmd32->chanlist_len);
-	err |= __put_user(temp.uint, &cmd->chanlist_len);
-	err |= __get_user(temp.uptr, &cmd32->data);
-	err |= __put_user(compat_ptr(temp.uptr), &cmd->data);
-	err |= __get_user(temp.uint, &cmd32->data_len);
-	err |= __put_user(temp.uint, &cmd->data_len);
-	return err ? -EFAULT : 0;
-}
-
-/* Copy native cmd structure to 32-bit cmd structure. */
-static int put_compat_cmd(struct comedi32_cmd_struct __user *cmd32,
-			  struct comedi_cmd __user *cmd)
-{
-	int err;
-	unsigned int temp;
-
-	/*
-	 * Copy back most of cmd structure.
-	 *
-	 * Assume the pointer values are already valid.
-	 * (Could use ptr_to_compat() to set them.)
-	 */
-	if (!access_ok(cmd, sizeof(*cmd)) ||
-	    !access_ok(cmd32, sizeof(*cmd32)))
-		return -EFAULT;
-
-	err = 0;
-	err |= __get_user(temp, &cmd->subdev);
-	err |= __put_user(temp, &cmd32->subdev);
-	err |= __get_user(temp, &cmd->flags);
-	err |= __put_user(temp, &cmd32->flags);
-	err |= __get_user(temp, &cmd->start_src);
-	err |= __put_user(temp, &cmd32->start_src);
-	err |= __get_user(temp, &cmd->start_arg);
-	err |= __put_user(temp, &cmd32->start_arg);
-	err |= __get_user(temp, &cmd->scan_begin_src);
-	err |= __put_user(temp, &cmd32->scan_begin_src);
-	err |= __get_user(temp, &cmd->scan_begin_arg);
-	err |= __put_user(temp, &cmd32->scan_begin_arg);
-	err |= __get_user(temp, &cmd->convert_src);
-	err |= __put_user(temp, &cmd32->convert_src);
-	err |= __get_user(temp, &cmd->convert_arg);
-	err |= __put_user(temp, &cmd32->convert_arg);
-	err |= __get_user(temp, &cmd->scan_end_src);
-	err |= __put_user(temp, &cmd32->scan_end_src);
-	err |= __get_user(temp, &cmd->scan_end_arg);
-	err |= __put_user(temp, &cmd32->scan_end_arg);
-	err |= __get_user(temp, &cmd->stop_src);
-	err |= __put_user(temp, &cmd32->stop_src);
-	err |= __get_user(temp, &cmd->stop_arg);
-	err |= __put_user(temp, &cmd32->stop_arg);
-	/* Assume chanlist pointer is unchanged. */
-	err |= __get_user(temp, &cmd->chanlist_len);
-	err |= __put_user(temp, &cmd32->chanlist_len);
-	/* Assume data pointer is unchanged. */
-	err |= __get_user(temp, &cmd->data_len);
-	err |= __put_user(temp, &cmd32->data_len);
-	return err ? -EFAULT : 0;
-}
-
-/* Handle 32-bit COMEDI_CMD ioctl. */
-static int compat_cmd(struct file *file, unsigned long arg)
-{
-	struct comedi_cmd __user *cmd;
-	struct comedi32_cmd_struct __user *cmd32;
-	int rc, err;
-
-	cmd32 = compat_ptr(arg);
-	cmd = compat_alloc_user_space(sizeof(*cmd));
-
-	rc = get_compat_cmd(cmd, cmd32);
-	if (rc)
-		return rc;
-
-	rc = translated_ioctl(file, COMEDI_CMD, (unsigned long)cmd);
-	if (rc == -EAGAIN) {
-		/* Special case: copy cmd back to user. */
-		err = put_compat_cmd(cmd32, cmd);
-		if (err)
-			rc = err;
-	}
-
-	return rc;
-}
-
-/* Handle 32-bit COMEDI_CMDTEST ioctl. */
-static int compat_cmdtest(struct file *file, unsigned long arg)
-{
-	struct comedi_cmd __user *cmd;
-	struct comedi32_cmd_struct __user *cmd32;
-	int rc, err;
-
-	cmd32 = compat_ptr(arg);
-	cmd = compat_alloc_user_space(sizeof(*cmd));
-
-	rc = get_compat_cmd(cmd, cmd32);
-	if (rc)
-		return rc;
-
-	rc = translated_ioctl(file, COMEDI_CMDTEST, (unsigned long)cmd);
-	if (rc < 0)
-		return rc;
-
-	err = put_compat_cmd(cmd32, cmd);
-	if (err)
-		rc = err;
-
-	return rc;
-}
-
-/* Copy 32-bit insn structure to native insn structure. */
-static int get_compat_insn(struct comedi_insn __user *insn,
-			   struct comedi32_insn_struct __user *insn32)
-{
-	int err;
-	union {
-		unsigned int uint;
-		compat_uptr_t uptr;
-	} temp;
-
-	/* Copy insn structure.  Ignore the unused members. */
-	err = 0;
-	if (!access_ok(insn32, sizeof(*insn32)) ||
-	    !access_ok(insn, sizeof(*insn)))
-		return -EFAULT;
-
-	err |= __get_user(temp.uint, &insn32->insn);
-	err |= __put_user(temp.uint, &insn->insn);
-	err |= __get_user(temp.uint, &insn32->n);
-	err |= __put_user(temp.uint, &insn->n);
-	err |= __get_user(temp.uptr, &insn32->data);
-	err |= __put_user(compat_ptr(temp.uptr), &insn->data);
-	err |= __get_user(temp.uint, &insn32->subdev);
-	err |= __put_user(temp.uint, &insn->subdev);
-	err |= __get_user(temp.uint, &insn32->chanspec);
-	err |= __put_user(temp.uint, &insn->chanspec);
-	return err ? -EFAULT : 0;
-}
-
-/* Handle 32-bit COMEDI_INSNLIST ioctl. */
-static int compat_insnlist(struct file *file, unsigned long arg)
-{
-	struct combined_insnlist {
-		struct comedi_insnlist insnlist;
-		struct comedi_insn insn[1];
-	} __user *s;
-	struct comedi32_insnlist_struct __user *insnlist32;
-	struct comedi32_insn_struct __user *insn32;
-	compat_uptr_t uptr;
-	unsigned int n_insns, n;
-	int err, rc;
-
-	insnlist32 = compat_ptr(arg);
-
-	/* Get 32-bit insnlist structure.  */
-	if (!access_ok(insnlist32, sizeof(*insnlist32)))
-		return -EFAULT;
-
-	err = 0;
-	err |= __get_user(n_insns, &insnlist32->n_insns);
-	err |= __get_user(uptr, &insnlist32->insns);
-	insn32 = compat_ptr(uptr);
-	if (err)
-		return -EFAULT;
-
-	/* Allocate user memory to copy insnlist and insns into. */
-	s = compat_alloc_user_space(offsetof(struct combined_insnlist,
-					     insn[n_insns]));
-
-	/* Set native insnlist structure. */
-	if (!access_ok(&s->insnlist, sizeof(s->insnlist)))
-		return -EFAULT;
-
-	err |= __put_user(n_insns, &s->insnlist.n_insns);
-	err |= __put_user(&s->insn[0], &s->insnlist.insns);
-	if (err)
-		return -EFAULT;
-
-	/* Copy insn structures. */
-	for (n = 0; n < n_insns; n++) {
-		rc = get_compat_insn(&s->insn[n], &insn32[n]);
-		if (rc)
-			return rc;
-	}
-
-	return translated_ioctl(file, COMEDI_INSNLIST,
-				(unsigned long)&s->insnlist);
-}
-
-/* Handle 32-bit COMEDI_INSN ioctl. */
-static int compat_insn(struct file *file, unsigned long arg)
-{
-	struct comedi_insn __user *insn;
-	struct comedi32_insn_struct __user *insn32;
-	int rc;
-
-	insn32 = compat_ptr(arg);
-	insn = compat_alloc_user_space(sizeof(*insn));
-
-	rc = get_compat_insn(insn, insn32);
-	if (rc)
-		return rc;
-
-	return translated_ioctl(file, COMEDI_INSN, (unsigned long)insn);
-}
-
-/*
- * compat_ioctl file operation.
- *
- * Returns -ENOIOCTLCMD for unrecognised ioctl codes.
- */
-long comedi_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-	int rc;
-
-	switch (cmd) {
-	case COMEDI_DEVCONFIG:
-	case COMEDI_DEVINFO:
-	case COMEDI_SUBDINFO:
-	case COMEDI_BUFCONFIG:
-	case COMEDI_BUFINFO:
-		/* Just need to translate the pointer argument. */
-		arg = (unsigned long)compat_ptr(arg);
-		rc = translated_ioctl(file, cmd, arg);
-		break;
-	case COMEDI_LOCK:
-	case COMEDI_UNLOCK:
-	case COMEDI_CANCEL:
-	case COMEDI_POLL:
-	case COMEDI_SETRSUBD:
-	case COMEDI_SETWSUBD:
-		/* No translation needed. */
-		rc = translated_ioctl(file, cmd, arg);
-		break;
-	case COMEDI32_CHANINFO:
-		rc = compat_chaninfo(file, arg);
-		break;
-	case COMEDI32_RANGEINFO:
-		rc = compat_rangeinfo(file, arg);
-		break;
-	case COMEDI32_CMD:
-		rc = compat_cmd(file, arg);
-		break;
-	case COMEDI32_CMDTEST:
-		rc = compat_cmdtest(file, arg);
-		break;
-	case COMEDI32_INSNLIST:
-		rc = compat_insnlist(file, arg);
-		break;
-	case COMEDI32_INSN:
-		rc = compat_insn(file, arg);
-		break;
-	default:
-		rc = -ENOIOCTLCMD;
-		break;
-	}
-	return rc;
-}
diff --git a/drivers/staging/comedi/comedi_compat32.h b/drivers/staging/comedi/comedi_compat32.h
deleted file mode 100644
index dc3e2a9442c7..000000000000
--- a/drivers/staging/comedi/comedi_compat32.h
+++ /dev/null
@@ -1,28 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0+ */
-/*
- * comedi/comedi_compat32.h
- * 32-bit ioctl compatibility for 64-bit comedi kernel module.
- *
- * Author: Ian Abbott, MEV Ltd. <abbotti@mev.co.uk>
- * Copyright (C) 2007 MEV Ltd. <http://www.mev.co.uk/>
- *
- * COMEDI - Linux Control and Measurement Device Interface
- * Copyright (C) 1997-2007 David A. Schleef <ds@schleef.org>
- */
-
-#ifndef _COMEDI_COMPAT32_H
-#define _COMEDI_COMPAT32_H
-
-#ifdef CONFIG_COMPAT
-
-struct file;
-long comedi_compat_ioctl(struct file *file, unsigned int cmd,
-			 unsigned long arg);
-
-#else /* CONFIG_COMPAT */
-
-#define comedi_compat_ioctl	NULL
-
-#endif /* CONFIG_COMPAT */
-
-#endif /* _COMEDI_COMPAT32_H */
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 08d1bbbebf2d..9dfb81dfe43c 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -4,13 +4,14 @@
  * comedi kernel module
  *
  * COMEDI - Linux Control and Measurement Device Interface
- * Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
+ * Copyright (C) 1997-2007 David A. Schleef <ds@schleef.org>
+ * compat ioctls:
+ * Author: Ian Abbott, MEV Ltd. <abbotti@mev.co.uk>
+ * Copyright (C) 2007 MEV Ltd. <http://www.mev.co.uk/>
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include "comedi_compat32.h"
-
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
@@ -27,6 +28,7 @@
 
 #include <linux/io.h>
 #include <linux/uaccess.h>
+#include <linux/compat.h>
 
 #include "comedi_internal.h"
 
@@ -2806,6 +2808,449 @@ static int comedi_close(struct inode *inode, struct file *file)
 	return 0;
 }
 
+#ifdef CONFIG_COMPAT
+
+#define COMEDI32_CHANINFO _IOR(CIO, 3, struct comedi32_chaninfo_struct)
+#define COMEDI32_RANGEINFO _IOR(CIO, 8, struct comedi32_rangeinfo_struct)
+/*
+ * N.B. COMEDI32_CMD and COMEDI_CMD ought to use _IOWR, not _IOR.
+ * It's too late to change it now, but it only affects the command number.
+ */
+#define COMEDI32_CMD _IOR(CIO, 9, struct comedi32_cmd_struct)
+/*
+ * N.B. COMEDI32_CMDTEST and COMEDI_CMDTEST ought to use _IOWR, not _IOR.
+ * It's too late to change it now, but it only affects the command number.
+ */
+#define COMEDI32_CMDTEST _IOR(CIO, 10, struct comedi32_cmd_struct)
+#define COMEDI32_INSNLIST _IOR(CIO, 11, struct comedi32_insnlist_struct)
+#define COMEDI32_INSN _IOR(CIO, 12, struct comedi32_insn_struct)
+
+struct comedi32_chaninfo_struct {
+	unsigned int subdev;
+	compat_uptr_t maxdata_list;	/* 32-bit 'unsigned int *' */
+	compat_uptr_t flaglist;	/* 32-bit 'unsigned int *' */
+	compat_uptr_t rangelist;	/* 32-bit 'unsigned int *' */
+	unsigned int unused[4];
+};
+
+struct comedi32_rangeinfo_struct {
+	unsigned int range_type;
+	compat_uptr_t range_ptr;	/* 32-bit 'void *' */
+};
+
+struct comedi32_cmd_struct {
+	unsigned int subdev;
+	unsigned int flags;
+	unsigned int start_src;
+	unsigned int start_arg;
+	unsigned int scan_begin_src;
+	unsigned int scan_begin_arg;
+	unsigned int convert_src;
+	unsigned int convert_arg;
+	unsigned int scan_end_src;
+	unsigned int scan_end_arg;
+	unsigned int stop_src;
+	unsigned int stop_arg;
+	compat_uptr_t chanlist;	/* 32-bit 'unsigned int *' */
+	unsigned int chanlist_len;
+	compat_uptr_t data;	/* 32-bit 'short *' */
+	unsigned int data_len;
+};
+
+struct comedi32_insn_struct {
+	unsigned int insn;
+	unsigned int n;
+	compat_uptr_t data;	/* 32-bit 'unsigned int *' */
+	unsigned int subdev;
+	unsigned int chanspec;
+	unsigned int unused[3];
+};
+
+struct comedi32_insnlist_struct {
+	unsigned int n_insns;
+	compat_uptr_t insns;	/* 32-bit 'struct comedi_insn *' */
+};
+
+/* Handle translated ioctl. */
+static int translated_ioctl(struct file *file, unsigned int cmd,
+			    unsigned long arg)
+{
+	if (file->f_op->unlocked_ioctl)
+		return file->f_op->unlocked_ioctl(file, cmd, arg);
+
+	return -ENOTTY;
+}
+
+/* Handle 32-bit COMEDI_CHANINFO ioctl. */
+static int compat_chaninfo(struct file *file, unsigned long arg)
+{
+	struct comedi_chaninfo __user *chaninfo;
+	struct comedi32_chaninfo_struct __user *chaninfo32;
+	int err;
+	union {
+		unsigned int uint;
+		compat_uptr_t uptr;
+	} temp;
+
+	chaninfo32 = compat_ptr(arg);
+	chaninfo = compat_alloc_user_space(sizeof(*chaninfo));
+
+	/* Copy chaninfo structure.  Ignore unused members. */
+	if (!access_ok(chaninfo32, sizeof(*chaninfo32)) ||
+	    !access_ok(chaninfo, sizeof(*chaninfo)))
+		return -EFAULT;
+
+	err = 0;
+	err |= __get_user(temp.uint, &chaninfo32->subdev);
+	err |= __put_user(temp.uint, &chaninfo->subdev);
+	err |= __get_user(temp.uptr, &chaninfo32->maxdata_list);
+	err |= __put_user(compat_ptr(temp.uptr), &chaninfo->maxdata_list);
+	err |= __get_user(temp.uptr, &chaninfo32->flaglist);
+	err |= __put_user(compat_ptr(temp.uptr), &chaninfo->flaglist);
+	err |= __get_user(temp.uptr, &chaninfo32->rangelist);
+	err |= __put_user(compat_ptr(temp.uptr), &chaninfo->rangelist);
+	if (err)
+		return -EFAULT;
+
+	return translated_ioctl(file, COMEDI_CHANINFO, (unsigned long)chaninfo);
+}
+
+/* Handle 32-bit COMEDI_RANGEINFO ioctl. */
+static int compat_rangeinfo(struct file *file, unsigned long arg)
+{
+	struct comedi_rangeinfo __user *rangeinfo;
+	struct comedi32_rangeinfo_struct __user *rangeinfo32;
+	int err;
+	union {
+		unsigned int uint;
+		compat_uptr_t uptr;
+	} temp;
+
+	rangeinfo32 = compat_ptr(arg);
+	rangeinfo = compat_alloc_user_space(sizeof(*rangeinfo));
+
+	/* Copy rangeinfo structure. */
+	if (!access_ok(rangeinfo32, sizeof(*rangeinfo32)) ||
+	    !access_ok(rangeinfo, sizeof(*rangeinfo)))
+		return -EFAULT;
+
+	err = 0;
+	err |= __get_user(temp.uint, &rangeinfo32->range_type);
+	err |= __put_user(temp.uint, &rangeinfo->range_type);
+	err |= __get_user(temp.uptr, &rangeinfo32->range_ptr);
+	err |= __put_user(compat_ptr(temp.uptr), &rangeinfo->range_ptr);
+	if (err)
+		return -EFAULT;
+
+	return translated_ioctl(file, COMEDI_RANGEINFO,
+				(unsigned long)rangeinfo);
+}
+
+/* Copy 32-bit cmd structure to native cmd structure. */
+static int get_compat_cmd(struct comedi_cmd __user *cmd,
+			  struct comedi32_cmd_struct __user *cmd32)
+{
+	int err;
+	union {
+		unsigned int uint;
+		compat_uptr_t uptr;
+	} temp;
+
+	/* Copy cmd structure. */
+	if (!access_ok(cmd32, sizeof(*cmd32)) ||
+	    !access_ok(cmd, sizeof(*cmd)))
+		return -EFAULT;
+
+	err = 0;
+	err |= __get_user(temp.uint, &cmd32->subdev);
+	err |= __put_user(temp.uint, &cmd->subdev);
+	err |= __get_user(temp.uint, &cmd32->flags);
+	err |= __put_user(temp.uint, &cmd->flags);
+	err |= __get_user(temp.uint, &cmd32->start_src);
+	err |= __put_user(temp.uint, &cmd->start_src);
+	err |= __get_user(temp.uint, &cmd32->start_arg);
+	err |= __put_user(temp.uint, &cmd->start_arg);
+	err |= __get_user(temp.uint, &cmd32->scan_begin_src);
+	err |= __put_user(temp.uint, &cmd->scan_begin_src);
+	err |= __get_user(temp.uint, &cmd32->scan_begin_arg);
+	err |= __put_user(temp.uint, &cmd->scan_begin_arg);
+	err |= __get_user(temp.uint, &cmd32->convert_src);
+	err |= __put_user(temp.uint, &cmd->convert_src);
+	err |= __get_user(temp.uint, &cmd32->convert_arg);
+	err |= __put_user(temp.uint, &cmd->convert_arg);
+	err |= __get_user(temp.uint, &cmd32->scan_end_src);
+	err |= __put_user(temp.uint, &cmd->scan_end_src);
+	err |= __get_user(temp.uint, &cmd32->scan_end_arg);
+	err |= __put_user(temp.uint, &cmd->scan_end_arg);
+	err |= __get_user(temp.uint, &cmd32->stop_src);
+	err |= __put_user(temp.uint, &cmd->stop_src);
+	err |= __get_user(temp.uint, &cmd32->stop_arg);
+	err |= __put_user(temp.uint, &cmd->stop_arg);
+	err |= __get_user(temp.uptr, &cmd32->chanlist);
+	err |= __put_user((unsigned int __force *)compat_ptr(temp.uptr),
+			  &cmd->chanlist);
+	err |= __get_user(temp.uint, &cmd32->chanlist_len);
+	err |= __put_user(temp.uint, &cmd->chanlist_len);
+	err |= __get_user(temp.uptr, &cmd32->data);
+	err |= __put_user(compat_ptr(temp.uptr), &cmd->data);
+	err |= __get_user(temp.uint, &cmd32->data_len);
+	err |= __put_user(temp.uint, &cmd->data_len);
+	return err ? -EFAULT : 0;
+}
+
+/* Copy native cmd structure to 32-bit cmd structure. */
+static int put_compat_cmd(struct comedi32_cmd_struct __user *cmd32,
+			  struct comedi_cmd __user *cmd)
+{
+	int err;
+	unsigned int temp;
+
+	/*
+	 * Copy back most of cmd structure.
+	 *
+	 * Assume the pointer values are already valid.
+	 * (Could use ptr_to_compat() to set them.)
+	 */
+	if (!access_ok(cmd, sizeof(*cmd)) ||
+	    !access_ok(cmd32, sizeof(*cmd32)))
+		return -EFAULT;
+
+	err = 0;
+	err |= __get_user(temp, &cmd->subdev);
+	err |= __put_user(temp, &cmd32->subdev);
+	err |= __get_user(temp, &cmd->flags);
+	err |= __put_user(temp, &cmd32->flags);
+	err |= __get_user(temp, &cmd->start_src);
+	err |= __put_user(temp, &cmd32->start_src);
+	err |= __get_user(temp, &cmd->start_arg);
+	err |= __put_user(temp, &cmd32->start_arg);
+	err |= __get_user(temp, &cmd->scan_begin_src);
+	err |= __put_user(temp, &cmd32->scan_begin_src);
+	err |= __get_user(temp, &cmd->scan_begin_arg);
+	err |= __put_user(temp, &cmd32->scan_begin_arg);
+	err |= __get_user(temp, &cmd->convert_src);
+	err |= __put_user(temp, &cmd32->convert_src);
+	err |= __get_user(temp, &cmd->convert_arg);
+	err |= __put_user(temp, &cmd32->convert_arg);
+	err |= __get_user(temp, &cmd->scan_end_src);
+	err |= __put_user(temp, &cmd32->scan_end_src);
+	err |= __get_user(temp, &cmd->scan_end_arg);
+	err |= __put_user(temp, &cmd32->scan_end_arg);
+	err |= __get_user(temp, &cmd->stop_src);
+	err |= __put_user(temp, &cmd32->stop_src);
+	err |= __get_user(temp, &cmd->stop_arg);
+	err |= __put_user(temp, &cmd32->stop_arg);
+	/* Assume chanlist pointer is unchanged. */
+	err |= __get_user(temp, &cmd->chanlist_len);
+	err |= __put_user(temp, &cmd32->chanlist_len);
+	/* Assume data pointer is unchanged. */
+	err |= __get_user(temp, &cmd->data_len);
+	err |= __put_user(temp, &cmd32->data_len);
+	return err ? -EFAULT : 0;
+}
+
+/* Handle 32-bit COMEDI_CMD ioctl. */
+static int compat_cmd(struct file *file, unsigned long arg)
+{
+	struct comedi_cmd __user *cmd;
+	struct comedi32_cmd_struct __user *cmd32;
+	int rc, err;
+
+	cmd32 = compat_ptr(arg);
+	cmd = compat_alloc_user_space(sizeof(*cmd));
+
+	rc = get_compat_cmd(cmd, cmd32);
+	if (rc)
+		return rc;
+
+	rc = translated_ioctl(file, COMEDI_CMD, (unsigned long)cmd);
+	if (rc == -EAGAIN) {
+		/* Special case: copy cmd back to user. */
+		err = put_compat_cmd(cmd32, cmd);
+		if (err)
+			rc = err;
+	}
+
+	return rc;
+}
+
+/* Handle 32-bit COMEDI_CMDTEST ioctl. */
+static int compat_cmdtest(struct file *file, unsigned long arg)
+{
+	struct comedi_cmd __user *cmd;
+	struct comedi32_cmd_struct __user *cmd32;
+	int rc, err;
+
+	cmd32 = compat_ptr(arg);
+	cmd = compat_alloc_user_space(sizeof(*cmd));
+
+	rc = get_compat_cmd(cmd, cmd32);
+	if (rc)
+		return rc;
+
+	rc = translated_ioctl(file, COMEDI_CMDTEST, (unsigned long)cmd);
+	if (rc < 0)
+		return rc;
+
+	err = put_compat_cmd(cmd32, cmd);
+	if (err)
+		rc = err;
+
+	return rc;
+}
+
+/* Copy 32-bit insn structure to native insn structure. */
+static int get_compat_insn(struct comedi_insn __user *insn,
+			   struct comedi32_insn_struct __user *insn32)
+{
+	int err;
+	union {
+		unsigned int uint;
+		compat_uptr_t uptr;
+	} temp;
+
+	/* Copy insn structure.  Ignore the unused members. */
+	err = 0;
+	if (!access_ok(insn32, sizeof(*insn32)) ||
+	    !access_ok(insn, sizeof(*insn)))
+		return -EFAULT;
+
+	err |= __get_user(temp.uint, &insn32->insn);
+	err |= __put_user(temp.uint, &insn->insn);
+	err |= __get_user(temp.uint, &insn32->n);
+	err |= __put_user(temp.uint, &insn->n);
+	err |= __get_user(temp.uptr, &insn32->data);
+	err |= __put_user(compat_ptr(temp.uptr), &insn->data);
+	err |= __get_user(temp.uint, &insn32->subdev);
+	err |= __put_user(temp.uint, &insn->subdev);
+	err |= __get_user(temp.uint, &insn32->chanspec);
+	err |= __put_user(temp.uint, &insn->chanspec);
+	return err ? -EFAULT : 0;
+}
+
+/* Handle 32-bit COMEDI_INSNLIST ioctl. */
+static int compat_insnlist(struct file *file, unsigned long arg)
+{
+	struct combined_insnlist {
+		struct comedi_insnlist insnlist;
+		struct comedi_insn insn[1];
+	} __user *s;
+	struct comedi32_insnlist_struct __user *insnlist32;
+	struct comedi32_insn_struct __user *insn32;
+	compat_uptr_t uptr;
+	unsigned int n_insns, n;
+	int err, rc;
+
+	insnlist32 = compat_ptr(arg);
+
+	/* Get 32-bit insnlist structure.  */
+	if (!access_ok(insnlist32, sizeof(*insnlist32)))
+		return -EFAULT;
+
+	err = 0;
+	err |= __get_user(n_insns, &insnlist32->n_insns);
+	err |= __get_user(uptr, &insnlist32->insns);
+	insn32 = compat_ptr(uptr);
+	if (err)
+		return -EFAULT;
+
+	/* Allocate user memory to copy insnlist and insns into. */
+	s = compat_alloc_user_space(offsetof(struct combined_insnlist,
+					     insn[n_insns]));
+
+	/* Set native insnlist structure. */
+	if (!access_ok(&s->insnlist, sizeof(s->insnlist)))
+		return -EFAULT;
+
+	err |= __put_user(n_insns, &s->insnlist.n_insns);
+	err |= __put_user(&s->insn[0], &s->insnlist.insns);
+	if (err)
+		return -EFAULT;
+
+	/* Copy insn structures. */
+	for (n = 0; n < n_insns; n++) {
+		rc = get_compat_insn(&s->insn[n], &insn32[n]);
+		if (rc)
+			return rc;
+	}
+
+	return translated_ioctl(file, COMEDI_INSNLIST,
+				(unsigned long)&s->insnlist);
+}
+
+/* Handle 32-bit COMEDI_INSN ioctl. */
+static int compat_insn(struct file *file, unsigned long arg)
+{
+	struct comedi_insn __user *insn;
+	struct comedi32_insn_struct __user *insn32;
+	int rc;
+
+	insn32 = compat_ptr(arg);
+	insn = compat_alloc_user_space(sizeof(*insn));
+
+	rc = get_compat_insn(insn, insn32);
+	if (rc)
+		return rc;
+
+	return translated_ioctl(file, COMEDI_INSN, (unsigned long)insn);
+}
+
+/*
+ * compat_ioctl file operation.
+ *
+ * Returns -ENOIOCTLCMD for unrecognised ioctl codes.
+ */
+static long comedi_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int rc;
+
+	switch (cmd) {
+	case COMEDI_DEVCONFIG:
+	case COMEDI_DEVINFO:
+	case COMEDI_SUBDINFO:
+	case COMEDI_BUFCONFIG:
+	case COMEDI_BUFINFO:
+		/* Just need to translate the pointer argument. */
+		arg = (unsigned long)compat_ptr(arg);
+		rc = translated_ioctl(file, cmd, arg);
+		break;
+	case COMEDI_LOCK:
+	case COMEDI_UNLOCK:
+	case COMEDI_CANCEL:
+	case COMEDI_POLL:
+	case COMEDI_SETRSUBD:
+	case COMEDI_SETWSUBD:
+		/* No translation needed. */
+		rc = translated_ioctl(file, cmd, arg);
+		break;
+	case COMEDI32_CHANINFO:
+		rc = compat_chaninfo(file, arg);
+		break;
+	case COMEDI32_RANGEINFO:
+		rc = compat_rangeinfo(file, arg);
+		break;
+	case COMEDI32_CMD:
+		rc = compat_cmd(file, arg);
+		break;
+	case COMEDI32_CMDTEST:
+		rc = compat_cmdtest(file, arg);
+		break;
+	case COMEDI32_INSNLIST:
+		rc = compat_insnlist(file, arg);
+		break;
+	case COMEDI32_INSN:
+		rc = compat_insn(file, arg);
+		break;
+	default:
+		rc = -ENOIOCTLCMD;
+		break;
+	}
+	return rc;
+}
+#else
+#define comedi_compat_ioctl NULL
+#endif
+
 static const struct file_operations comedi_fops = {
 	.owner = THIS_MODULE,
 	.unlocked_ioctl = comedi_unlocked_ioctl,

From 5c6a8747e0cff47071d6ad3fcfe6f86713cf543a Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 25 Apr 2020 18:23:17 -0400
Subject: [PATCH 02/10] comedi: get rid of indirection via translated_ioctl()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/staging/comedi/comedi_fops.c | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 9dfb81dfe43c..ecd29f28673c 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2871,16 +2871,6 @@ struct comedi32_insnlist_struct {
 	compat_uptr_t insns;	/* 32-bit 'struct comedi_insn *' */
 };
 
-/* Handle translated ioctl. */
-static int translated_ioctl(struct file *file, unsigned int cmd,
-			    unsigned long arg)
-{
-	if (file->f_op->unlocked_ioctl)
-		return file->f_op->unlocked_ioctl(file, cmd, arg);
-
-	return -ENOTTY;
-}
-
 /* Handle 32-bit COMEDI_CHANINFO ioctl. */
 static int compat_chaninfo(struct file *file, unsigned long arg)
 {
@@ -2912,7 +2902,7 @@ static int compat_chaninfo(struct file *file, unsigned long arg)
 	if (err)
 		return -EFAULT;
 
-	return translated_ioctl(file, COMEDI_CHANINFO, (unsigned long)chaninfo);
+	return comedi_unlocked_ioctl(file, COMEDI_CHANINFO, (unsigned long)chaninfo);
 }
 
 /* Handle 32-bit COMEDI_RANGEINFO ioctl. */
@@ -2942,7 +2932,7 @@ static int compat_rangeinfo(struct file *file, unsigned long arg)
 	if (err)
 		return -EFAULT;
 
-	return translated_ioctl(file, COMEDI_RANGEINFO,
+	return comedi_unlocked_ioctl(file, COMEDI_RANGEINFO,
 				(unsigned long)rangeinfo);
 }
 
@@ -3063,7 +3053,7 @@ static int compat_cmd(struct file *file, unsigned long arg)
 	if (rc)
 		return rc;
 
-	rc = translated_ioctl(file, COMEDI_CMD, (unsigned long)cmd);
+	rc = comedi_unlocked_ioctl(file, COMEDI_CMD, (unsigned long)cmd);
 	if (rc == -EAGAIN) {
 		/* Special case: copy cmd back to user. */
 		err = put_compat_cmd(cmd32, cmd);
@@ -3088,7 +3078,7 @@ static int compat_cmdtest(struct file *file, unsigned long arg)
 	if (rc)
 		return rc;
 
-	rc = translated_ioctl(file, COMEDI_CMDTEST, (unsigned long)cmd);
+	rc = comedi_unlocked_ioctl(file, COMEDI_CMDTEST, (unsigned long)cmd);
 	if (rc < 0)
 		return rc;
 
@@ -3174,7 +3164,7 @@ static int compat_insnlist(struct file *file, unsigned long arg)
 			return rc;
 	}
 
-	return translated_ioctl(file, COMEDI_INSNLIST,
+	return comedi_unlocked_ioctl(file, COMEDI_INSNLIST,
 				(unsigned long)&s->insnlist);
 }
 
@@ -3192,7 +3182,7 @@ static int compat_insn(struct file *file, unsigned long arg)
 	if (rc)
 		return rc;
 
-	return translated_ioctl(file, COMEDI_INSN, (unsigned long)insn);
+	return comedi_unlocked_ioctl(file, COMEDI_INSN, (unsigned long)insn);
 }
 
 /*
@@ -3212,7 +3202,7 @@ static long comedi_compat_ioctl(struct file *file, unsigned int cmd, unsigned lo
 	case COMEDI_BUFINFO:
 		/* Just need to translate the pointer argument. */
 		arg = (unsigned long)compat_ptr(arg);
-		rc = translated_ioctl(file, cmd, arg);
+		rc = comedi_unlocked_ioctl(file, cmd, arg);
 		break;
 	case COMEDI_LOCK:
 	case COMEDI_UNLOCK:
@@ -3221,7 +3211,7 @@ static long comedi_compat_ioctl(struct file *file, unsigned int cmd, unsigned lo
 	case COMEDI_SETRSUBD:
 	case COMEDI_SETWSUBD:
 		/* No translation needed. */
-		rc = translated_ioctl(file, cmd, arg);
+		rc = comedi_unlocked_ioctl(file, cmd, arg);
 		break;
 	case COMEDI32_CHANINFO:
 		rc = compat_chaninfo(file, arg);

From 3fbfd2223a271426509830e6340c386a1054cfad Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 25 Apr 2020 18:35:03 -0400
Subject: [PATCH 03/10] comedi: get rid of compat_alloc_user_space() mess in
 COMEDI_CHANINFO compat

Just take copy_from_user() out of do_chaninfo_ioctl() into the caller and
have compat_chaninfo() build a native version and pass it to do_chaninfo_ioctl()
directly.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/staging/comedi/comedi_fops.c | 68 ++++++++++++----------------
 1 file changed, 30 insertions(+), 38 deletions(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index ecd29f28673c..ab811735cd1b 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1049,31 +1049,28 @@ static int do_subdinfo_ioctl(struct comedi_device *dev,
  *	array of range table lengths to chaninfo->range_table_list if requested
  */
 static int do_chaninfo_ioctl(struct comedi_device *dev,
-			     struct comedi_chaninfo __user *arg)
+			     struct comedi_chaninfo *it)
 {
 	struct comedi_subdevice *s;
-	struct comedi_chaninfo it;
 
 	lockdep_assert_held(&dev->mutex);
-	if (copy_from_user(&it, arg, sizeof(it)))
-		return -EFAULT;
 
-	if (it.subdev >= dev->n_subdevices)
+	if (it->subdev >= dev->n_subdevices)
 		return -EINVAL;
-	s = &dev->subdevices[it.subdev];
+	s = &dev->subdevices[it->subdev];
 
-	if (it.maxdata_list) {
+	if (it->maxdata_list) {
 		if (s->maxdata || !s->maxdata_list)
 			return -EINVAL;
-		if (copy_to_user(it.maxdata_list, s->maxdata_list,
+		if (copy_to_user(it->maxdata_list, s->maxdata_list,
 				 s->n_chan * sizeof(unsigned int)))
 			return -EFAULT;
 	}
 
-	if (it.flaglist)
+	if (it->flaglist)
 		return -EINVAL;	/* flaglist not supported */
 
-	if (it.rangelist) {
+	if (it->rangelist) {
 		int i;
 
 		if (!s->range_table_list)
@@ -1081,9 +1078,9 @@ static int do_chaninfo_ioctl(struct comedi_device *dev,
 		for (i = 0; i < s->n_chan; i++) {
 			int x;
 
-			x = (dev->minor << 28) | (it.subdev << 24) | (i << 16) |
+			x = (dev->minor << 28) | (it->subdev << 24) | (i << 16) |
 			    (s->range_table_list[i]->length);
-			if (put_user(x, it.rangelist + i))
+			if (put_user(x, it->rangelist + i))
 				return -EFAULT;
 		}
 	}
@@ -2205,9 +2202,14 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
 				       (struct comedi_subdinfo __user *)arg,
 				       file);
 		break;
-	case COMEDI_CHANINFO:
-		rc = do_chaninfo_ioctl(dev, (void __user *)arg);
+	case COMEDI_CHANINFO: {
+		struct comedi_chaninfo it;
+		if (copy_from_user(&it, (void __user *)arg, sizeof(it)))
+			rc = -EFAULT;
+		else
+			rc = do_chaninfo_ioctl(dev, &it);
 		break;
+	}
 	case COMEDI_RANGEINFO:
 		rc = do_rangeinfo_ioctl(dev, (void __user *)arg);
 		break;
@@ -2874,35 +2876,25 @@ struct comedi32_insnlist_struct {
 /* Handle 32-bit COMEDI_CHANINFO ioctl. */
 static int compat_chaninfo(struct file *file, unsigned long arg)
 {
-	struct comedi_chaninfo __user *chaninfo;
-	struct comedi32_chaninfo_struct __user *chaninfo32;
+	struct comedi_file *cfp = file->private_data;
+	struct comedi_device *dev = cfp->dev;
+	struct comedi32_chaninfo_struct chaninfo32;
+	struct comedi_chaninfo chaninfo;
 	int err;
-	union {
-		unsigned int uint;
-		compat_uptr_t uptr;
-	} temp;
 
-	chaninfo32 = compat_ptr(arg);
-	chaninfo = compat_alloc_user_space(sizeof(*chaninfo));
-
-	/* Copy chaninfo structure.  Ignore unused members. */
-	if (!access_ok(chaninfo32, sizeof(*chaninfo32)) ||
-	    !access_ok(chaninfo, sizeof(*chaninfo)))
+	if (copy_from_user(&chaninfo32, compat_ptr(arg), sizeof(chaninfo32)))
 		return -EFAULT;
 
-	err = 0;
-	err |= __get_user(temp.uint, &chaninfo32->subdev);
-	err |= __put_user(temp.uint, &chaninfo->subdev);
-	err |= __get_user(temp.uptr, &chaninfo32->maxdata_list);
-	err |= __put_user(compat_ptr(temp.uptr), &chaninfo->maxdata_list);
-	err |= __get_user(temp.uptr, &chaninfo32->flaglist);
-	err |= __put_user(compat_ptr(temp.uptr), &chaninfo->flaglist);
-	err |= __get_user(temp.uptr, &chaninfo32->rangelist);
-	err |= __put_user(compat_ptr(temp.uptr), &chaninfo->rangelist);
-	if (err)
-		return -EFAULT;
+	memset(&chaninfo, 0, sizeof(chaninfo));
+	chaninfo.subdev = chaninfo32.subdev;
+	chaninfo.maxdata_list = compat_ptr(chaninfo32.maxdata_list);
+	chaninfo.flaglist = compat_ptr(chaninfo32.flaglist);
+	chaninfo.rangelist = compat_ptr(chaninfo32.rangelist);
 
-	return comedi_unlocked_ioctl(file, COMEDI_CHANINFO, (unsigned long)chaninfo);
+	mutex_lock(&dev->mutex);
+	err = do_chaninfo_ioctl(dev, &chaninfo);
+	mutex_unlock(&dev->mutex);
+	return err;
 }
 
 /* Handle 32-bit COMEDI_RANGEINFO ioctl. */

From 388138764e2549520afd0b3b4e15de8deb592ff6 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 25 Apr 2020 18:44:30 -0400
Subject: [PATCH 04/10] comedi: get rid of compat_alloc_user_space() mess in
 COMEDI_RANGEINFO compat

Just take copy_from_user() out of do_rangeing_ioctl() into the caller and
have compat_rangeinfo() build a native version and pass it to do_rangeinfo_ioctl()
directly.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/staging/comedi/comedi_fops.c     | 43 +++++++++++-------------
 drivers/staging/comedi/comedi_internal.h |  2 +-
 drivers/staging/comedi/range.c           | 17 ++++------
 3 files changed, 27 insertions(+), 35 deletions(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index ab811735cd1b..d96dc85d8a98 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2210,9 +2210,14 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
 			rc = do_chaninfo_ioctl(dev, &it);
 		break;
 	}
-	case COMEDI_RANGEINFO:
-		rc = do_rangeinfo_ioctl(dev, (void __user *)arg);
+	case COMEDI_RANGEINFO: {
+		struct comedi_rangeinfo it;
+		if (copy_from_user(&it, (void __user *)arg, sizeof(it)))
+			rc = -EFAULT;
+		else
+			rc = do_rangeinfo_ioctl(dev, &it);
 		break;
+	}
 	case COMEDI_BUFINFO:
 		rc = do_bufinfo_ioctl(dev,
 				      (struct comedi_bufinfo __user *)arg,
@@ -2900,32 +2905,22 @@ static int compat_chaninfo(struct file *file, unsigned long arg)
 /* Handle 32-bit COMEDI_RANGEINFO ioctl. */
 static int compat_rangeinfo(struct file *file, unsigned long arg)
 {
-	struct comedi_rangeinfo __user *rangeinfo;
-	struct comedi32_rangeinfo_struct __user *rangeinfo32;
+	struct comedi_file *cfp = file->private_data;
+	struct comedi_device *dev = cfp->dev;
+	struct comedi32_rangeinfo_struct rangeinfo32;
+	struct comedi_rangeinfo rangeinfo;
 	int err;
-	union {
-		unsigned int uint;
-		compat_uptr_t uptr;
-	} temp;
 
-	rangeinfo32 = compat_ptr(arg);
-	rangeinfo = compat_alloc_user_space(sizeof(*rangeinfo));
-
-	/* Copy rangeinfo structure. */
-	if (!access_ok(rangeinfo32, sizeof(*rangeinfo32)) ||
-	    !access_ok(rangeinfo, sizeof(*rangeinfo)))
+	if (copy_from_user(&rangeinfo32, compat_ptr(arg), sizeof(rangeinfo32)))
 		return -EFAULT;
+	memset(&rangeinfo, 0, sizeof(rangeinfo));
+	rangeinfo.range_type = rangeinfo32.range_type;
+	rangeinfo.range_ptr = compat_ptr(rangeinfo32.range_ptr);
 
-	err = 0;
-	err |= __get_user(temp.uint, &rangeinfo32->range_type);
-	err |= __put_user(temp.uint, &rangeinfo->range_type);
-	err |= __get_user(temp.uptr, &rangeinfo32->range_ptr);
-	err |= __put_user(compat_ptr(temp.uptr), &rangeinfo->range_ptr);
-	if (err)
-		return -EFAULT;
-
-	return comedi_unlocked_ioctl(file, COMEDI_RANGEINFO,
-				(unsigned long)rangeinfo);
+	mutex_lock(&dev->mutex);
+	err = do_rangeinfo_ioctl(dev, &rangeinfo);
+	mutex_unlock(&dev->mutex);
+	return err;
 }
 
 /* Copy 32-bit cmd structure to native cmd structure. */
diff --git a/drivers/staging/comedi/comedi_internal.h b/drivers/staging/comedi/comedi_internal.h
index 515f293a5d26..7c8f18f55122 100644
--- a/drivers/staging/comedi/comedi_internal.h
+++ b/drivers/staging/comedi/comedi_internal.h
@@ -18,7 +18,7 @@ struct comedi_subdevice;
 struct device;
 
 int do_rangeinfo_ioctl(struct comedi_device *dev,
-		       struct comedi_rangeinfo __user *arg);
+		       struct comedi_rangeinfo *it);
 struct comedi_device *comedi_alloc_board_minor(struct device *hardware_device);
 void comedi_release_hardware_device(struct device *hardware_device);
 int comedi_alloc_subdevice_minor(struct comedi_subdevice *s);
diff --git a/drivers/staging/comedi/range.c b/drivers/staging/comedi/range.c
index 89d599877445..a4e6fe0fb729 100644
--- a/drivers/staging/comedi/range.c
+++ b/drivers/staging/comedi/range.c
@@ -46,17 +46,14 @@ EXPORT_SYMBOL_GPL(range_unknown);
  *	array of comedi_krange structures to rangeinfo->range_ptr pointer
  */
 int do_rangeinfo_ioctl(struct comedi_device *dev,
-		       struct comedi_rangeinfo __user *arg)
+		       struct comedi_rangeinfo *it)
 {
-	struct comedi_rangeinfo it;
 	int subd, chan;
 	const struct comedi_lrange *lr;
 	struct comedi_subdevice *s;
 
-	if (copy_from_user(&it, arg, sizeof(struct comedi_rangeinfo)))
-		return -EFAULT;
-	subd = (it.range_type >> 24) & 0xf;
-	chan = (it.range_type >> 16) & 0xff;
+	subd = (it->range_type >> 24) & 0xf;
+	chan = (it->range_type >> 16) & 0xff;
 
 	if (!dev->attached)
 		return -EINVAL;
@@ -73,15 +70,15 @@ int do_rangeinfo_ioctl(struct comedi_device *dev,
 		return -EINVAL;
 	}
 
-	if (RANGE_LENGTH(it.range_type) != lr->length) {
+	if (RANGE_LENGTH(it->range_type) != lr->length) {
 		dev_dbg(dev->class_dev,
 			"wrong length %d should be %d (0x%08x)\n",
-			RANGE_LENGTH(it.range_type),
-			lr->length, it.range_type);
+			RANGE_LENGTH(it->range_type),
+			lr->length, it->range_type);
 		return -EINVAL;
 	}
 
-	if (copy_to_user(it.range_ptr, lr->range,
+	if (copy_to_user(it->range_ptr, lr->range,
 			 sizeof(struct comedi_krange) * lr->length))
 		return -EFAULT;
 

From aa332e6759fac21b454e4959703777c771a9cd93 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 25 Apr 2020 20:11:57 -0400
Subject: [PATCH 05/10] comedi: get rid of compat_alloc_user_space() mess in
 COMEDI_INSN compat

Just take copy_from_user() out of do_insn_ioctl() into the caller and
have compat_insn() build a native version and pass it to do_insn_ioctl()
directly.

One difference from the previous commits is that the helper used to
convert 32bit variant to native has two users - compat_insn() and
compat_insnlist().  The latter will be converted in next commit;
for now we simply split the helper in two variants - "userland 32bit
to kernel native" and "userland 32bit to userland native".  The latter
is renamed old get_compat_insn(); it will be gone in the next commit.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/staging/comedi/comedi_fops.c | 74 ++++++++++++++++++----------
 1 file changed, 47 insertions(+), 27 deletions(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index d96dc85d8a98..0e7ba0d3fa03 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1615,22 +1615,19 @@ static int do_insnlist_ioctl(struct comedi_device *dev,
  *	data (for reads) to insn->data pointer
  */
 static int do_insn_ioctl(struct comedi_device *dev,
-			 struct comedi_insn __user *arg, void *file)
+			 struct comedi_insn *insn, void *file)
 {
-	struct comedi_insn insn;
 	unsigned int *data = NULL;
 	unsigned int n_data = MIN_SAMPLES;
 	int ret = 0;
 
 	lockdep_assert_held(&dev->mutex);
-	if (copy_from_user(&insn, arg, sizeof(insn)))
-		return -EFAULT;
 
-	n_data = max(n_data, insn.n);
+	n_data = max(n_data, insn->n);
 
 	/* This is where the behavior of insn and insnlist deviate. */
-	if (insn.n > MAX_SAMPLES) {
-		insn.n = MAX_SAMPLES;
+	if (insn->n > MAX_SAMPLES) {
+		insn->n = MAX_SAMPLES;
 		n_data = MAX_SAMPLES;
 	}
 
@@ -1640,26 +1637,26 @@ static int do_insn_ioctl(struct comedi_device *dev,
 		goto error;
 	}
 
-	if (insn.insn & INSN_MASK_WRITE) {
+	if (insn->insn & INSN_MASK_WRITE) {
 		if (copy_from_user(data,
-				   insn.data,
-				   insn.n * sizeof(unsigned int))) {
+				   insn->data,
+				   insn->n * sizeof(unsigned int))) {
 			ret = -EFAULT;
 			goto error;
 		}
 	}
-	ret = parse_insn(dev, &insn, data, file);
+	ret = parse_insn(dev, insn, data, file);
 	if (ret < 0)
 		goto error;
-	if (insn.insn & INSN_MASK_READ) {
-		if (copy_to_user(insn.data,
+	if (insn->insn & INSN_MASK_READ) {
+		if (copy_to_user(insn->data,
 				 data,
-				 insn.n * sizeof(unsigned int))) {
+				 insn->n * sizeof(unsigned int))) {
 			ret = -EFAULT;
 			goto error;
 		}
 	}
-	ret = insn.n;
+	ret = insn->n;
 
 error:
 	kfree(data);
@@ -2244,10 +2241,14 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
 				       (struct comedi_insnlist __user *)arg,
 				       file);
 		break;
-	case COMEDI_INSN:
-		rc = do_insn_ioctl(dev, (struct comedi_insn __user *)arg,
-				   file);
+	case COMEDI_INSN: {
+		struct comedi_insn insn;
+		if (copy_from_user(&insn, (void __user *)arg, sizeof(insn)))
+			rc = -EFAULT;
+		else
+			rc = do_insn_ioctl(dev, &insn, file);
 		break;
+	}
 	case COMEDI_POLL:
 		rc = do_poll_ioctl(dev, arg, file);
 		break;
@@ -3077,7 +3078,25 @@ static int compat_cmdtest(struct file *file, unsigned long arg)
 }
 
 /* Copy 32-bit insn structure to native insn structure. */
-static int get_compat_insn(struct comedi_insn __user *insn,
+static int get_compat_insn(struct comedi_insn *insn,
+			   struct comedi32_insn_struct __user *insn32)
+{
+	struct comedi32_insn_struct v32;
+
+	/* Copy insn structure.  Ignore the unused members. */
+	if (copy_from_user(&v32, insn32, sizeof(v32)))
+		return -EFAULT;
+	memset(insn, 0, sizeof(*insn));
+	insn->insn = v32.insn;
+	insn->n = v32.n;
+	insn->data = compat_ptr(v32.data);
+	insn->subdev = v32.subdev;
+	insn->chanspec = v32.chanspec;
+	return 0;
+}
+
+/* Copy 32-bit insn structure to native insn structure. */
+static int __get_compat_insn(struct comedi_insn __user *insn,
 			   struct comedi32_insn_struct __user *insn32)
 {
 	int err;
@@ -3146,7 +3165,7 @@ static int compat_insnlist(struct file *file, unsigned long arg)
 
 	/* Copy insn structures. */
 	for (n = 0; n < n_insns; n++) {
-		rc = get_compat_insn(&s->insn[n], &insn32[n]);
+		rc = __get_compat_insn(&s->insn[n], &insn32[n]);
 		if (rc)
 			return rc;
 	}
@@ -3158,18 +3177,19 @@ static int compat_insnlist(struct file *file, unsigned long arg)
 /* Handle 32-bit COMEDI_INSN ioctl. */
 static int compat_insn(struct file *file, unsigned long arg)
 {
-	struct comedi_insn __user *insn;
-	struct comedi32_insn_struct __user *insn32;
+	struct comedi_file *cfp = file->private_data;
+	struct comedi_device *dev = cfp->dev;
+	struct comedi_insn insn;
 	int rc;
 
-	insn32 = compat_ptr(arg);
-	insn = compat_alloc_user_space(sizeof(*insn));
-
-	rc = get_compat_insn(insn, insn32);
+	rc = get_compat_insn(&insn, (void __user *)arg);
 	if (rc)
 		return rc;
 
-	return comedi_unlocked_ioctl(file, COMEDI_INSN, (unsigned long)insn);
+	mutex_lock(&dev->mutex);
+	rc = do_insn_ioctl(dev, &insn, file);
+	mutex_unlock(&dev->mutex);
+	return rc;
 }
 
 /*

From b8d47d8813055ce38c0d2ad913d5462017e52692 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 25 Apr 2020 20:33:04 -0400
Subject: [PATCH 06/10] comedi: get rid of compat_alloc_user_space() mess in
 COMEDI_INSNLIST compat

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/staging/comedi/comedi_fops.c | 138 ++++++++++-----------------
 1 file changed, 48 insertions(+), 90 deletions(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 0e7ba0d3fa03..10ab24019fa5 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1520,34 +1520,19 @@ static int parse_insn(struct comedi_device *dev, struct comedi_insn *insn,
 #define MIN_SAMPLES 16
 #define MAX_SAMPLES 65536
 static int do_insnlist_ioctl(struct comedi_device *dev,
-			     struct comedi_insnlist __user *arg, void *file)
+			     struct comedi_insn *insns,
+			     unsigned int n_insns,
+			     void *file)
 {
-	struct comedi_insnlist insnlist;
-	struct comedi_insn *insns = NULL;
 	unsigned int *data = NULL;
 	unsigned int max_n_data_required = MIN_SAMPLES;
 	int i = 0;
 	int ret = 0;
 
 	lockdep_assert_held(&dev->mutex);
-	if (copy_from_user(&insnlist, arg, sizeof(insnlist)))
-		return -EFAULT;
-
-	insns = kcalloc(insnlist.n_insns, sizeof(*insns), GFP_KERNEL);
-	if (!insns) {
-		ret = -ENOMEM;
-		goto error;
-	}
-
-	if (copy_from_user(insns, insnlist.insns,
-			   sizeof(*insns) * insnlist.n_insns)) {
-		dev_dbg(dev->class_dev, "copy_from_user failed\n");
-		ret = -EFAULT;
-		goto error;
-	}
 
 	/* Determine maximum memory needed for all instructions. */
-	for (i = 0; i < insnlist.n_insns; ++i) {
+	for (i = 0; i < n_insns; ++i) {
 		if (insns[i].n > MAX_SAMPLES) {
 			dev_dbg(dev->class_dev,
 				"number of samples too large\n");
@@ -1565,7 +1550,7 @@ static int do_insnlist_ioctl(struct comedi_device *dev,
 		goto error;
 	}
 
-	for (i = 0; i < insnlist.n_insns; ++i) {
+	for (i = 0; i < n_insns; ++i) {
 		if (insns[i].insn & INSN_MASK_WRITE) {
 			if (copy_from_user(data, insns[i].data,
 					   insns[i].n * sizeof(unsigned int))) {
@@ -1592,7 +1577,6 @@ static int do_insnlist_ioctl(struct comedi_device *dev,
 	}
 
 error:
-	kfree(insns);
 	kfree(data);
 
 	if (ret < 0)
@@ -2236,11 +2220,30 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
 		rc = do_cmdtest_ioctl(dev, (struct comedi_cmd __user *)arg,
 				      file);
 		break;
-	case COMEDI_INSNLIST:
-		rc = do_insnlist_ioctl(dev,
-				       (struct comedi_insnlist __user *)arg,
-				       file);
+	case COMEDI_INSNLIST: {
+		struct comedi_insnlist insnlist;
+		struct comedi_insn *insns = NULL;
+
+		if (copy_from_user(&insnlist, (void __user *)arg,
+				   sizeof(insnlist))) {
+			rc = -EFAULT;
+			break;
+		}
+		insns = kcalloc(insnlist.n_insns, sizeof(*insns), GFP_KERNEL);
+		if (!insns) {
+			rc = -ENOMEM;
+			break;
+		}
+		if (copy_from_user(insns, insnlist.insns,
+				   sizeof(*insns) * insnlist.n_insns)) {
+			rc = -EFAULT;
+			kfree(insns);
+			break;
+		}
+		rc = do_insnlist_ioctl(dev, insns, insnlist.n_insns, file);
+		kfree(insns);
 		break;
+	}
 	case COMEDI_INSN: {
 		struct comedi_insn insn;
 		if (copy_from_user(&insn, (void __user *)arg, sizeof(insn)))
@@ -3095,83 +3098,38 @@ static int get_compat_insn(struct comedi_insn *insn,
 	return 0;
 }
 
-/* Copy 32-bit insn structure to native insn structure. */
-static int __get_compat_insn(struct comedi_insn __user *insn,
-			   struct comedi32_insn_struct __user *insn32)
-{
-	int err;
-	union {
-		unsigned int uint;
-		compat_uptr_t uptr;
-	} temp;
-
-	/* Copy insn structure.  Ignore the unused members. */
-	err = 0;
-	if (!access_ok(insn32, sizeof(*insn32)) ||
-	    !access_ok(insn, sizeof(*insn)))
-		return -EFAULT;
-
-	err |= __get_user(temp.uint, &insn32->insn);
-	err |= __put_user(temp.uint, &insn->insn);
-	err |= __get_user(temp.uint, &insn32->n);
-	err |= __put_user(temp.uint, &insn->n);
-	err |= __get_user(temp.uptr, &insn32->data);
-	err |= __put_user(compat_ptr(temp.uptr), &insn->data);
-	err |= __get_user(temp.uint, &insn32->subdev);
-	err |= __put_user(temp.uint, &insn->subdev);
-	err |= __get_user(temp.uint, &insn32->chanspec);
-	err |= __put_user(temp.uint, &insn->chanspec);
-	return err ? -EFAULT : 0;
-}
-
 /* Handle 32-bit COMEDI_INSNLIST ioctl. */
 static int compat_insnlist(struct file *file, unsigned long arg)
 {
-	struct combined_insnlist {
-		struct comedi_insnlist insnlist;
-		struct comedi_insn insn[1];
-	} __user *s;
-	struct comedi32_insnlist_struct __user *insnlist32;
+	struct comedi_file *cfp = file->private_data;
+	struct comedi_device *dev = cfp->dev;
+	struct comedi32_insnlist_struct insnlist32;
 	struct comedi32_insn_struct __user *insn32;
-	compat_uptr_t uptr;
-	unsigned int n_insns, n;
-	int err, rc;
+	struct comedi_insn *insns;
+	unsigned int n;
+	int rc;
 
-	insnlist32 = compat_ptr(arg);
-
-	/* Get 32-bit insnlist structure.  */
-	if (!access_ok(insnlist32, sizeof(*insnlist32)))
+	if (copy_from_user(&insnlist32, compat_ptr(arg), sizeof(insnlist32)))
 		return -EFAULT;
 
-	err = 0;
-	err |= __get_user(n_insns, &insnlist32->n_insns);
-	err |= __get_user(uptr, &insnlist32->insns);
-	insn32 = compat_ptr(uptr);
-	if (err)
-		return -EFAULT;
-
-	/* Allocate user memory to copy insnlist and insns into. */
-	s = compat_alloc_user_space(offsetof(struct combined_insnlist,
-					     insn[n_insns]));
-
-	/* Set native insnlist structure. */
-	if (!access_ok(&s->insnlist, sizeof(s->insnlist)))
-		return -EFAULT;
-
-	err |= __put_user(n_insns, &s->insnlist.n_insns);
-	err |= __put_user(&s->insn[0], &s->insnlist.insns);
-	if (err)
-		return -EFAULT;
+	insns = kcalloc(insnlist32.n_insns, sizeof(*insns), GFP_KERNEL);
+	if (!insns)
+		return -ENOMEM;
 
 	/* Copy insn structures. */
-	for (n = 0; n < n_insns; n++) {
-		rc = __get_compat_insn(&s->insn[n], &insn32[n]);
-		if (rc)
+	insn32 = compat_ptr(insnlist32.insns);
+	for (n = 0; n < insnlist32.n_insns; n++) {
+		rc = get_compat_insn(insns + n, insn32 + n);
+		if (rc) {
+			kfree(insns);
 			return rc;
+		}
 	}
 
-	return comedi_unlocked_ioctl(file, COMEDI_INSNLIST,
-				(unsigned long)&s->insnlist);
+	mutex_lock(&dev->mutex);
+	rc = do_insnlist_ioctl(dev, insns, insnlist32.n_insns, file);
+	mutex_unlock(&dev->mutex);
+	return rc;
 }
 
 /* Handle 32-bit COMEDI_INSN ioctl. */

From 00035beeec2c067a8094d3d86b34cc797c3d6b21 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 26 Apr 2020 08:46:04 -0400
Subject: [PATCH 07/10] comedi: lift copy_from_user() into callers of
 __comedi_get_user_cmd()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/staging/comedi/comedi_fops.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 10ab24019fa5..c136cb2f676a 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1649,17 +1649,11 @@ static int do_insn_ioctl(struct comedi_device *dev,
 }
 
 static int __comedi_get_user_cmd(struct comedi_device *dev,
-				 struct comedi_cmd __user *arg,
 				 struct comedi_cmd *cmd)
 {
 	struct comedi_subdevice *s;
 
 	lockdep_assert_held(&dev->mutex);
-	if (copy_from_user(cmd, arg, sizeof(*cmd))) {
-		dev_dbg(dev->class_dev, "bad cmd address\n");
-		return -EFAULT;
-	}
-
 	if (cmd->subdev >= dev->n_subdevices) {
 		dev_dbg(dev->class_dev, "%d no such subdevice\n", cmd->subdev);
 		return -ENODEV;
@@ -1757,8 +1751,13 @@ static int do_cmd_ioctl(struct comedi_device *dev,
 
 	lockdep_assert_held(&dev->mutex);
 
+	if (copy_from_user(&cmd, arg, sizeof(cmd))) {
+		dev_dbg(dev->class_dev, "bad cmd address\n");
+		return -EFAULT;
+	}
+
 	/* get the user's cmd and do some simple validation */
-	ret = __comedi_get_user_cmd(dev, arg, &cmd);
+	ret = __comedi_get_user_cmd(dev, &cmd);
 	if (ret)
 		return ret;
 
@@ -1866,8 +1865,13 @@ static int do_cmdtest_ioctl(struct comedi_device *dev,
 
 	lockdep_assert_held(&dev->mutex);
 
+	if (copy_from_user(&cmd, arg, sizeof(cmd))) {
+		dev_dbg(dev->class_dev, "bad cmd address\n");
+		return -EFAULT;
+	}
+
 	/* get the user's cmd and do some simple validation */
-	ret = __comedi_get_user_cmd(dev, arg, &cmd);
+	ret = __comedi_get_user_cmd(dev, &cmd);
 	if (ret)
 		return ret;
 

From f0e4de5cd0bb99a82445c5a3a876f162052689f8 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 26 Apr 2020 08:56:55 -0400
Subject: [PATCH 08/10] comedi: do_cmdtest_ioctl(): lift copyin/copyout into
 the caller

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/staging/comedi/comedi_fops.c | 45 ++++++++++++++--------------
 1 file changed, 22 insertions(+), 23 deletions(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index c136cb2f676a..74020fee0ae9 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1856,49 +1856,39 @@ static int do_cmd_ioctl(struct comedi_device *dev,
  *	possibly modified comedi_cmd structure
  */
 static int do_cmdtest_ioctl(struct comedi_device *dev,
-			    struct comedi_cmd __user *arg, void *file)
+			    struct comedi_cmd *cmd, bool *copy, void *file)
 {
-	struct comedi_cmd cmd;
 	struct comedi_subdevice *s;
 	unsigned int __user *user_chanlist;
 	int ret;
 
 	lockdep_assert_held(&dev->mutex);
 
-	if (copy_from_user(&cmd, arg, sizeof(cmd))) {
-		dev_dbg(dev->class_dev, "bad cmd address\n");
-		return -EFAULT;
-	}
-
-	/* get the user's cmd and do some simple validation */
-	ret = __comedi_get_user_cmd(dev, &cmd);
+	/* do some simple cmd validation */
+	ret = __comedi_get_user_cmd(dev, cmd);
 	if (ret)
 		return ret;
 
 	/* save user's chanlist pointer so it can be restored later */
-	user_chanlist = (unsigned int __user *)cmd.chanlist;
+	user_chanlist = (unsigned int __user *)cmd->chanlist;
 
-	s = &dev->subdevices[cmd.subdev];
+	s = &dev->subdevices[cmd->subdev];
 
 	/* user_chanlist can be NULL for COMEDI_CMDTEST ioctl */
 	if (user_chanlist) {
 		/* load channel/gain list */
-		ret = __comedi_get_user_chanlist(dev, s, user_chanlist, &cmd);
+		ret = __comedi_get_user_chanlist(dev, s, user_chanlist, cmd);
 		if (ret)
 			return ret;
 	}
 
-	ret = s->do_cmdtest(dev, s, &cmd);
+	ret = s->do_cmdtest(dev, s, cmd);
 
-	kfree(cmd.chanlist);	/* free kernel copy of user chanlist */
+	kfree(cmd->chanlist);	/* free kernel copy of user chanlist */
 
 	/* restore chanlist pointer before copying back */
-	cmd.chanlist = (unsigned int __force *)user_chanlist;
-
-	if (copy_to_user(arg, &cmd, sizeof(cmd))) {
-		dev_dbg(dev->class_dev, "bad cmd address\n");
-		ret = -EFAULT;
-	}
+	cmd->chanlist = (unsigned int __force *)user_chanlist;
+	*copy = true;
 
 	return ret;
 }
@@ -2220,10 +2210,19 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
 	case COMEDI_CMD:
 		rc = do_cmd_ioctl(dev, (struct comedi_cmd __user *)arg, file);
 		break;
-	case COMEDI_CMDTEST:
-		rc = do_cmdtest_ioctl(dev, (struct comedi_cmd __user *)arg,
-				      file);
+	case COMEDI_CMDTEST: {
+		struct comedi_cmd cmd;
+		bool copy = false;
+
+		if (copy_from_user(&cmd, (void __user *)arg, sizeof(cmd))) {
+			rc = -EFAULT;
+			break;
+		}
+		rc = do_cmdtest_ioctl(dev, &cmd, &copy, file);
+		if (copy && copy_to_user((void __user *)arg, &cmd, sizeof(cmd)))
+			rc = -EFAULT;
 		break;
+	}
 	case COMEDI_INSNLIST: {
 		struct comedi_insnlist insnlist;
 		struct comedi_insn *insns = NULL;

From 0a3ccc75a95ff682de9315dee7e55efde1d5e30c Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 26 Apr 2020 09:01:49 -0400
Subject: [PATCH 09/10] comedi: do_cmd_ioctl(): lift copyin/copyout into the
 caller

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/staging/comedi/comedi_fops.c | 48 ++++++++++++++--------------
 1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 74020fee0ae9..c40df64e3ec7 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1741,9 +1741,8 @@ static int __comedi_get_user_chanlist(struct comedi_device *dev,
  *	possibly modified comedi_cmd structure (when -EAGAIN returned)
  */
 static int do_cmd_ioctl(struct comedi_device *dev,
-			struct comedi_cmd __user *arg, void *file)
+			struct comedi_cmd *cmd, bool *copy, void *file)
 {
-	struct comedi_cmd cmd;
 	struct comedi_subdevice *s;
 	struct comedi_async *async;
 	unsigned int __user *user_chanlist;
@@ -1751,20 +1750,15 @@ static int do_cmd_ioctl(struct comedi_device *dev,
 
 	lockdep_assert_held(&dev->mutex);
 
-	if (copy_from_user(&cmd, arg, sizeof(cmd))) {
-		dev_dbg(dev->class_dev, "bad cmd address\n");
-		return -EFAULT;
-	}
-
-	/* get the user's cmd and do some simple validation */
-	ret = __comedi_get_user_cmd(dev, &cmd);
+	/* do some simple cmd validation */
+	ret = __comedi_get_user_cmd(dev, cmd);
 	if (ret)
 		return ret;
 
 	/* save user's chanlist pointer so it can be restored later */
-	user_chanlist = (unsigned int __user *)cmd.chanlist;
+	user_chanlist = (unsigned int __user *)cmd->chanlist;
 
-	s = &dev->subdevices[cmd.subdev];
+	s = &dev->subdevices[cmd->subdev];
 	async = s->async;
 
 	/* are we locked? (ioctl lock) */
@@ -1780,13 +1774,13 @@ static int do_cmd_ioctl(struct comedi_device *dev,
 	}
 
 	/* make sure channel/gain list isn't too short */
-	if (cmd.chanlist_len < 1) {
+	if (cmd->chanlist_len < 1) {
 		dev_dbg(dev->class_dev, "channel/gain list too short %u < 1\n",
-			cmd.chanlist_len);
+			cmd->chanlist_len);
 		return -EINVAL;
 	}
 
-	async->cmd = cmd;
+	async->cmd = *cmd;
 	async->cmd.data = NULL;
 
 	/* load channel/gain list */
@@ -1798,15 +1792,11 @@ static int do_cmd_ioctl(struct comedi_device *dev,
 
 	if (async->cmd.flags & CMDF_BOGUS || ret) {
 		dev_dbg(dev->class_dev, "test returned %d\n", ret);
-		cmd = async->cmd;
+		*cmd = async->cmd;
 		/* restore chanlist pointer before copying back */
-		cmd.chanlist = (unsigned int __force *)user_chanlist;
-		cmd.data = NULL;
-		if (copy_to_user(arg, &cmd, sizeof(cmd))) {
-			dev_dbg(dev->class_dev, "fault writing cmd\n");
-			ret = -EFAULT;
-			goto cleanup;
-		}
+		cmd->chanlist = (unsigned int __force *)user_chanlist;
+		cmd->data = NULL;
+		*copy = true;
 		ret = -EAGAIN;
 		goto cleanup;
 	}
@@ -2207,9 +2197,19 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
 	case COMEDI_CANCEL:
 		rc = do_cancel_ioctl(dev, arg, file);
 		break;
-	case COMEDI_CMD:
-		rc = do_cmd_ioctl(dev, (struct comedi_cmd __user *)arg, file);
+	case COMEDI_CMD: {
+		struct comedi_cmd cmd;
+		bool copy = false;
+
+		if (copy_from_user(&cmd, (void __user *)arg, sizeof(cmd))) {
+			rc = -EFAULT;
+			break;
+		}
+		rc = do_cmd_ioctl(dev, &cmd, &copy, file);
+		if (copy && copy_to_user((void __user *)arg, &cmd, sizeof(cmd)))
+			rc = -EFAULT;
 		break;
+	}
 	case COMEDI_CMDTEST: {
 		struct comedi_cmd cmd;
 		bool copy = false;

From bac42fb21259783cb748ae54227a5e755340a396 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 26 Apr 2020 09:27:23 -0400
Subject: [PATCH 10/10] comedi: get rid of compat_alloc_user_space() mess in
 COMEDI_CMD{,TEST} compat

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/staging/comedi/comedi_fops.c | 175 ++++++++++-----------------
 1 file changed, 63 insertions(+), 112 deletions(-)

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index c40df64e3ec7..dd14c2935292 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2931,155 +2931,106 @@ static int compat_rangeinfo(struct file *file, unsigned long arg)
 }
 
 /* Copy 32-bit cmd structure to native cmd structure. */
-static int get_compat_cmd(struct comedi_cmd __user *cmd,
+static int get_compat_cmd(struct comedi_cmd *cmd,
 			  struct comedi32_cmd_struct __user *cmd32)
 {
-	int err;
-	union {
-		unsigned int uint;
-		compat_uptr_t uptr;
-	} temp;
+	struct comedi32_cmd_struct v32;
 
-	/* Copy cmd structure. */
-	if (!access_ok(cmd32, sizeof(*cmd32)) ||
-	    !access_ok(cmd, sizeof(*cmd)))
+	if (copy_from_user(&v32, cmd32, sizeof(v32)))
 		return -EFAULT;
 
-	err = 0;
-	err |= __get_user(temp.uint, &cmd32->subdev);
-	err |= __put_user(temp.uint, &cmd->subdev);
-	err |= __get_user(temp.uint, &cmd32->flags);
-	err |= __put_user(temp.uint, &cmd->flags);
-	err |= __get_user(temp.uint, &cmd32->start_src);
-	err |= __put_user(temp.uint, &cmd->start_src);
-	err |= __get_user(temp.uint, &cmd32->start_arg);
-	err |= __put_user(temp.uint, &cmd->start_arg);
-	err |= __get_user(temp.uint, &cmd32->scan_begin_src);
-	err |= __put_user(temp.uint, &cmd->scan_begin_src);
-	err |= __get_user(temp.uint, &cmd32->scan_begin_arg);
-	err |= __put_user(temp.uint, &cmd->scan_begin_arg);
-	err |= __get_user(temp.uint, &cmd32->convert_src);
-	err |= __put_user(temp.uint, &cmd->convert_src);
-	err |= __get_user(temp.uint, &cmd32->convert_arg);
-	err |= __put_user(temp.uint, &cmd->convert_arg);
-	err |= __get_user(temp.uint, &cmd32->scan_end_src);
-	err |= __put_user(temp.uint, &cmd->scan_end_src);
-	err |= __get_user(temp.uint, &cmd32->scan_end_arg);
-	err |= __put_user(temp.uint, &cmd->scan_end_arg);
-	err |= __get_user(temp.uint, &cmd32->stop_src);
-	err |= __put_user(temp.uint, &cmd->stop_src);
-	err |= __get_user(temp.uint, &cmd32->stop_arg);
-	err |= __put_user(temp.uint, &cmd->stop_arg);
-	err |= __get_user(temp.uptr, &cmd32->chanlist);
-	err |= __put_user((unsigned int __force *)compat_ptr(temp.uptr),
-			  &cmd->chanlist);
-	err |= __get_user(temp.uint, &cmd32->chanlist_len);
-	err |= __put_user(temp.uint, &cmd->chanlist_len);
-	err |= __get_user(temp.uptr, &cmd32->data);
-	err |= __put_user(compat_ptr(temp.uptr), &cmd->data);
-	err |= __get_user(temp.uint, &cmd32->data_len);
-	err |= __put_user(temp.uint, &cmd->data_len);
-	return err ? -EFAULT : 0;
+	cmd->subdev = v32.subdev;
+	cmd->flags = v32.flags;
+	cmd->start_src = v32.start_src;
+	cmd->start_arg = v32.start_arg;
+	cmd->scan_begin_src = v32.scan_begin_src;
+	cmd->scan_begin_arg = v32.scan_begin_arg;
+	cmd->convert_src = v32.convert_src;
+	cmd->convert_arg = v32.convert_arg;
+	cmd->scan_end_src = v32.scan_end_src;
+	cmd->scan_end_arg = v32.scan_end_arg;
+	cmd->stop_src = v32.stop_src;
+	cmd->stop_arg = v32.stop_arg;
+	cmd->chanlist = compat_ptr(v32.chanlist);
+	cmd->chanlist_len = v32.chanlist_len;
+	cmd->data = compat_ptr(v32.data);
+	cmd->data_len = v32.data_len;
+	return 0;
 }
 
 /* Copy native cmd structure to 32-bit cmd structure. */
 static int put_compat_cmd(struct comedi32_cmd_struct __user *cmd32,
-			  struct comedi_cmd __user *cmd)
+			  struct comedi_cmd *cmd)
 {
-	int err;
-	unsigned int temp;
+	struct comedi32_cmd_struct v32;
 
-	/*
-	 * Copy back most of cmd structure.
-	 *
-	 * Assume the pointer values are already valid.
-	 * (Could use ptr_to_compat() to set them.)
-	 */
-	if (!access_ok(cmd, sizeof(*cmd)) ||
-	    !access_ok(cmd32, sizeof(*cmd32)))
-		return -EFAULT;
-
-	err = 0;
-	err |= __get_user(temp, &cmd->subdev);
-	err |= __put_user(temp, &cmd32->subdev);
-	err |= __get_user(temp, &cmd->flags);
-	err |= __put_user(temp, &cmd32->flags);
-	err |= __get_user(temp, &cmd->start_src);
-	err |= __put_user(temp, &cmd32->start_src);
-	err |= __get_user(temp, &cmd->start_arg);
-	err |= __put_user(temp, &cmd32->start_arg);
-	err |= __get_user(temp, &cmd->scan_begin_src);
-	err |= __put_user(temp, &cmd32->scan_begin_src);
-	err |= __get_user(temp, &cmd->scan_begin_arg);
-	err |= __put_user(temp, &cmd32->scan_begin_arg);
-	err |= __get_user(temp, &cmd->convert_src);
-	err |= __put_user(temp, &cmd32->convert_src);
-	err |= __get_user(temp, &cmd->convert_arg);
-	err |= __put_user(temp, &cmd32->convert_arg);
-	err |= __get_user(temp, &cmd->scan_end_src);
-	err |= __put_user(temp, &cmd32->scan_end_src);
-	err |= __get_user(temp, &cmd->scan_end_arg);
-	err |= __put_user(temp, &cmd32->scan_end_arg);
-	err |= __get_user(temp, &cmd->stop_src);
-	err |= __put_user(temp, &cmd32->stop_src);
-	err |= __get_user(temp, &cmd->stop_arg);
-	err |= __put_user(temp, &cmd32->stop_arg);
+	memset(&v32, 0, sizeof(v32));
+	v32.subdev = cmd->subdev;
+	v32.flags = cmd->flags;
+	v32.start_src = cmd->start_src;
+	v32.start_arg = cmd->start_arg;
+	v32.scan_begin_src = cmd->scan_begin_src;
+	v32.scan_begin_arg = cmd->scan_begin_arg;
+	v32.convert_src = cmd->convert_src;
+	v32.convert_arg = cmd->convert_arg;
+	v32.scan_end_src = cmd->scan_end_src;
+	v32.scan_end_arg = cmd->scan_end_arg;
+	v32.stop_src = cmd->stop_src;
+	v32.stop_arg = cmd->stop_arg;
 	/* Assume chanlist pointer is unchanged. */
-	err |= __get_user(temp, &cmd->chanlist_len);
-	err |= __put_user(temp, &cmd32->chanlist_len);
-	/* Assume data pointer is unchanged. */
-	err |= __get_user(temp, &cmd->data_len);
-	err |= __put_user(temp, &cmd32->data_len);
-	return err ? -EFAULT : 0;
+	v32.chanlist = ptr_to_compat(cmd->chanlist);
+	v32.chanlist_len = cmd->chanlist_len;
+	v32.data = ptr_to_compat(cmd->data);
+	v32.data_len = cmd->data_len;
+	return copy_to_user(cmd32, &v32, sizeof(v32));
 }
 
 /* Handle 32-bit COMEDI_CMD ioctl. */
 static int compat_cmd(struct file *file, unsigned long arg)
 {
-	struct comedi_cmd __user *cmd;
-	struct comedi32_cmd_struct __user *cmd32;
+	struct comedi_file *cfp = file->private_data;
+	struct comedi_device *dev = cfp->dev;
+	struct comedi_cmd cmd;
+	bool copy = false;
 	int rc, err;
 
-	cmd32 = compat_ptr(arg);
-	cmd = compat_alloc_user_space(sizeof(*cmd));
-
-	rc = get_compat_cmd(cmd, cmd32);
+	rc = get_compat_cmd(&cmd, compat_ptr(arg));
 	if (rc)
 		return rc;
 
-	rc = comedi_unlocked_ioctl(file, COMEDI_CMD, (unsigned long)cmd);
-	if (rc == -EAGAIN) {
+	mutex_lock(&dev->mutex);
+	rc = do_cmd_ioctl(dev, &cmd, &copy, file);
+	mutex_unlock(&dev->mutex);
+	if (copy) {
 		/* Special case: copy cmd back to user. */
-		err = put_compat_cmd(cmd32, cmd);
+		err = put_compat_cmd(compat_ptr(arg), &cmd);
 		if (err)
 			rc = err;
 	}
-
 	return rc;
 }
 
 /* Handle 32-bit COMEDI_CMDTEST ioctl. */
 static int compat_cmdtest(struct file *file, unsigned long arg)
 {
-	struct comedi_cmd __user *cmd;
-	struct comedi32_cmd_struct __user *cmd32;
+	struct comedi_file *cfp = file->private_data;
+	struct comedi_device *dev = cfp->dev;
+	struct comedi_cmd cmd;
+	bool copy = false;
 	int rc, err;
 
-	cmd32 = compat_ptr(arg);
-	cmd = compat_alloc_user_space(sizeof(*cmd));
-
-	rc = get_compat_cmd(cmd, cmd32);
+	rc = get_compat_cmd(&cmd, compat_ptr(arg));
 	if (rc)
 		return rc;
 
-	rc = comedi_unlocked_ioctl(file, COMEDI_CMDTEST, (unsigned long)cmd);
-	if (rc < 0)
-		return rc;
-
-	err = put_compat_cmd(cmd32, cmd);
-	if (err)
-		rc = err;
-
+	mutex_lock(&dev->mutex);
+	rc = do_cmdtest_ioctl(dev, &cmd, &copy, file);
+	mutex_unlock(&dev->mutex);
+	if (copy) {
+		err = put_compat_cmd(compat_ptr(arg), &cmd);
+		if (err)
+			rc = err;
+	}
 	return rc;
 }