mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 18:46:43 +07:00
a8472b4bb1
Pull AIO leak fixes from Ben LaHaise: "I've put these two patches plus Linus's change through a round of tests, and it passes millions of iterations of the aio numa migratepage test, as well as a number of repetitions of a few simple read and write tests. The first patch fixes the memory leak Kent introduced, while the second patch makes aio_migratepage() much more paranoid and robust" * git://git.kvack.org/~bcrl/aio-next: aio/migratepages: make aio migrate pages sane aio: fix kioctx leak introduced by "aio: Fix a trinity splat"
1596 lines
38 KiB
C
1596 lines
38 KiB
C
/*
|
|
* An async IO implementation for Linux
|
|
* Written by Benjamin LaHaise <bcrl@kvack.org>
|
|
*
|
|
* Implements an efficient asynchronous io interface.
|
|
*
|
|
* Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.
|
|
*
|
|
* See ../COPYING for licensing terms.
|
|
*/
|
|
#define pr_fmt(fmt) "%s: " fmt, __func__
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/time.h>
|
|
#include <linux/aio_abi.h>
|
|
#include <linux/export.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/uio.h>
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/file.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/mmu_context.h>
|
|
#include <linux/percpu.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/timer.h>
|
|
#include <linux/aio.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/workqueue.h>
|
|
#include <linux/security.h>
|
|
#include <linux/eventfd.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/compat.h>
|
|
#include <linux/migrate.h>
|
|
#include <linux/ramfs.h>
|
|
#include <linux/percpu-refcount.h>
|
|
#include <linux/mount.h>
|
|
|
|
#include <asm/kmap_types.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
#include "internal.h"
|
|
|
|
#define AIO_RING_MAGIC 0xa10a10a1
|
|
#define AIO_RING_COMPAT_FEATURES 1
|
|
#define AIO_RING_INCOMPAT_FEATURES 0
|
|
struct aio_ring {
|
|
unsigned id; /* kernel internal index number */
|
|
unsigned nr; /* number of io_events */
|
|
unsigned head;
|
|
unsigned tail;
|
|
|
|
unsigned magic;
|
|
unsigned compat_features;
|
|
unsigned incompat_features;
|
|
unsigned header_length; /* size of aio_ring */
|
|
|
|
|
|
struct io_event io_events[0];
|
|
}; /* 128 bytes + ring size */
|
|
|
|
#define AIO_RING_PAGES 8
|
|
|
|
struct kioctx_table {
|
|
struct rcu_head rcu;
|
|
unsigned nr;
|
|
struct kioctx *table[];
|
|
};
|
|
|
|
struct kioctx_cpu {
|
|
unsigned reqs_available;
|
|
};
|
|
|
|
struct kioctx {
|
|
struct percpu_ref users;
|
|
atomic_t dead;
|
|
|
|
struct percpu_ref reqs;
|
|
|
|
unsigned long user_id;
|
|
|
|
struct __percpu kioctx_cpu *cpu;
|
|
|
|
/*
|
|
* For percpu reqs_available, number of slots we move to/from global
|
|
* counter at a time:
|
|
*/
|
|
unsigned req_batch;
|
|
/*
|
|
* This is what userspace passed to io_setup(), it's not used for
|
|
* anything but counting against the global max_reqs quota.
|
|
*
|
|
* The real limit is nr_events - 1, which will be larger (see
|
|
* aio_setup_ring())
|
|
*/
|
|
unsigned max_reqs;
|
|
|
|
/* Size of ringbuffer, in units of struct io_event */
|
|
unsigned nr_events;
|
|
|
|
unsigned long mmap_base;
|
|
unsigned long mmap_size;
|
|
|
|
struct page **ring_pages;
|
|
long nr_pages;
|
|
|
|
struct work_struct free_work;
|
|
|
|
struct {
|
|
/*
|
|
* This counts the number of available slots in the ringbuffer,
|
|
* so we avoid overflowing it: it's decremented (if positive)
|
|
* when allocating a kiocb and incremented when the resulting
|
|
* io_event is pulled off the ringbuffer.
|
|
*
|
|
* We batch accesses to it with a percpu version.
|
|
*/
|
|
atomic_t reqs_available;
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
struct {
|
|
spinlock_t ctx_lock;
|
|
struct list_head active_reqs; /* used for cancellation */
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
struct {
|
|
struct mutex ring_lock;
|
|
wait_queue_head_t wait;
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
struct {
|
|
unsigned tail;
|
|
spinlock_t completion_lock;
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
struct page *internal_pages[AIO_RING_PAGES];
|
|
struct file *aio_ring_file;
|
|
|
|
unsigned id;
|
|
};
|
|
|
|
/*------ sysctl variables----*/
|
|
static DEFINE_SPINLOCK(aio_nr_lock);
|
|
unsigned long aio_nr; /* current system wide number of aio requests */
|
|
unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
|
|
/*----end sysctl variables---*/
|
|
|
|
static struct kmem_cache *kiocb_cachep;
|
|
static struct kmem_cache *kioctx_cachep;
|
|
|
|
static struct vfsmount *aio_mnt;
|
|
|
|
static const struct file_operations aio_ring_fops;
|
|
static const struct address_space_operations aio_ctx_aops;
|
|
|
|
static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
|
|
{
|
|
struct qstr this = QSTR_INIT("[aio]", 5);
|
|
struct file *file;
|
|
struct path path;
|
|
struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
|
|
if (IS_ERR(inode))
|
|
return ERR_CAST(inode);
|
|
|
|
inode->i_mapping->a_ops = &aio_ctx_aops;
|
|
inode->i_mapping->private_data = ctx;
|
|
inode->i_size = PAGE_SIZE * nr_pages;
|
|
|
|
path.dentry = d_alloc_pseudo(aio_mnt->mnt_sb, &this);
|
|
if (!path.dentry) {
|
|
iput(inode);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
path.mnt = mntget(aio_mnt);
|
|
|
|
d_instantiate(path.dentry, inode);
|
|
file = alloc_file(&path, FMODE_READ | FMODE_WRITE, &aio_ring_fops);
|
|
if (IS_ERR(file)) {
|
|
path_put(&path);
|
|
return file;
|
|
}
|
|
|
|
file->f_flags = O_RDWR;
|
|
file->private_data = ctx;
|
|
return file;
|
|
}
|
|
|
|
static struct dentry *aio_mount(struct file_system_type *fs_type,
|
|
int flags, const char *dev_name, void *data)
|
|
{
|
|
static const struct dentry_operations ops = {
|
|
.d_dname = simple_dname,
|
|
};
|
|
return mount_pseudo(fs_type, "aio:", NULL, &ops, 0xa10a10a1);
|
|
}
|
|
|
|
/* aio_setup
|
|
* Creates the slab caches used by the aio routines, panic on
|
|
* failure as this is done early during the boot sequence.
|
|
*/
|
|
static int __init aio_setup(void)
|
|
{
|
|
static struct file_system_type aio_fs = {
|
|
.name = "aio",
|
|
.mount = aio_mount,
|
|
.kill_sb = kill_anon_super,
|
|
};
|
|
aio_mnt = kern_mount(&aio_fs);
|
|
if (IS_ERR(aio_mnt))
|
|
panic("Failed to create aio fs mount.");
|
|
|
|
kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
|
|
kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
|
|
|
|
pr_debug("sizeof(struct page) = %zu\n", sizeof(struct page));
|
|
|
|
return 0;
|
|
}
|
|
__initcall(aio_setup);
|
|
|
|
static void put_aio_ring_file(struct kioctx *ctx)
|
|
{
|
|
struct file *aio_ring_file = ctx->aio_ring_file;
|
|
if (aio_ring_file) {
|
|
truncate_setsize(aio_ring_file->f_inode, 0);
|
|
|
|
/* Prevent further access to the kioctx from migratepages */
|
|
spin_lock(&aio_ring_file->f_inode->i_mapping->private_lock);
|
|
aio_ring_file->f_inode->i_mapping->private_data = NULL;
|
|
ctx->aio_ring_file = NULL;
|
|
spin_unlock(&aio_ring_file->f_inode->i_mapping->private_lock);
|
|
|
|
fput(aio_ring_file);
|
|
}
|
|
}
|
|
|
|
static void aio_free_ring(struct kioctx *ctx)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < ctx->nr_pages; i++) {
|
|
struct page *page;
|
|
pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
|
|
page_count(ctx->ring_pages[i]));
|
|
page = ctx->ring_pages[i];
|
|
if (!page)
|
|
continue;
|
|
ctx->ring_pages[i] = NULL;
|
|
put_page(page);
|
|
}
|
|
|
|
put_aio_ring_file(ctx);
|
|
|
|
if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
|
|
kfree(ctx->ring_pages);
|
|
ctx->ring_pages = NULL;
|
|
}
|
|
}
|
|
|
|
static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
vma->vm_ops = &generic_file_vm_ops;
|
|
return 0;
|
|
}
|
|
|
|
static const struct file_operations aio_ring_fops = {
|
|
.mmap = aio_ring_mmap,
|
|
};
|
|
|
|
static int aio_set_page_dirty(struct page *page)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#if IS_ENABLED(CONFIG_MIGRATION)
|
|
static int aio_migratepage(struct address_space *mapping, struct page *new,
|
|
struct page *old, enum migrate_mode mode)
|
|
{
|
|
struct kioctx *ctx;
|
|
unsigned long flags;
|
|
int rc;
|
|
|
|
rc = 0;
|
|
|
|
/* Make sure the old page hasn't already been changed */
|
|
spin_lock(&mapping->private_lock);
|
|
ctx = mapping->private_data;
|
|
if (ctx) {
|
|
pgoff_t idx;
|
|
spin_lock_irqsave(&ctx->completion_lock, flags);
|
|
idx = old->index;
|
|
if (idx < (pgoff_t)ctx->nr_pages) {
|
|
if (ctx->ring_pages[idx] != old)
|
|
rc = -EAGAIN;
|
|
} else
|
|
rc = -EINVAL;
|
|
spin_unlock_irqrestore(&ctx->completion_lock, flags);
|
|
} else
|
|
rc = -EINVAL;
|
|
spin_unlock(&mapping->private_lock);
|
|
|
|
if (rc != 0)
|
|
return rc;
|
|
|
|
/* Writeback must be complete */
|
|
BUG_ON(PageWriteback(old));
|
|
get_page(new);
|
|
|
|
rc = migrate_page_move_mapping(mapping, new, old, NULL, mode, 1);
|
|
if (rc != MIGRATEPAGE_SUCCESS) {
|
|
put_page(new);
|
|
return rc;
|
|
}
|
|
|
|
/* We can potentially race against kioctx teardown here. Use the
|
|
* address_space's private data lock to protect the mapping's
|
|
* private_data.
|
|
*/
|
|
spin_lock(&mapping->private_lock);
|
|
ctx = mapping->private_data;
|
|
if (ctx) {
|
|
pgoff_t idx;
|
|
spin_lock_irqsave(&ctx->completion_lock, flags);
|
|
migrate_page_copy(new, old);
|
|
idx = old->index;
|
|
if (idx < (pgoff_t)ctx->nr_pages) {
|
|
/* And only do the move if things haven't changed */
|
|
if (ctx->ring_pages[idx] == old)
|
|
ctx->ring_pages[idx] = new;
|
|
else
|
|
rc = -EAGAIN;
|
|
} else
|
|
rc = -EINVAL;
|
|
spin_unlock_irqrestore(&ctx->completion_lock, flags);
|
|
} else
|
|
rc = -EBUSY;
|
|
spin_unlock(&mapping->private_lock);
|
|
|
|
if (rc == MIGRATEPAGE_SUCCESS)
|
|
put_page(old);
|
|
else
|
|
put_page(new);
|
|
|
|
return rc;
|
|
}
|
|
#endif
|
|
|
|
static const struct address_space_operations aio_ctx_aops = {
|
|
.set_page_dirty = aio_set_page_dirty,
|
|
#if IS_ENABLED(CONFIG_MIGRATION)
|
|
.migratepage = aio_migratepage,
|
|
#endif
|
|
};
|
|
|
|
static int aio_setup_ring(struct kioctx *ctx)
|
|
{
|
|
struct aio_ring *ring;
|
|
unsigned nr_events = ctx->max_reqs;
|
|
struct mm_struct *mm = current->mm;
|
|
unsigned long size, unused;
|
|
int nr_pages;
|
|
int i;
|
|
struct file *file;
|
|
|
|
/* Compensate for the ring buffer's head/tail overlap entry */
|
|
nr_events += 2; /* 1 is required, 2 for good luck */
|
|
|
|
size = sizeof(struct aio_ring);
|
|
size += sizeof(struct io_event) * nr_events;
|
|
|
|
nr_pages = PFN_UP(size);
|
|
if (nr_pages < 0)
|
|
return -EINVAL;
|
|
|
|
file = aio_private_file(ctx, nr_pages);
|
|
if (IS_ERR(file)) {
|
|
ctx->aio_ring_file = NULL;
|
|
return -EAGAIN;
|
|
}
|
|
|
|
ctx->aio_ring_file = file;
|
|
nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
|
|
/ sizeof(struct io_event);
|
|
|
|
ctx->ring_pages = ctx->internal_pages;
|
|
if (nr_pages > AIO_RING_PAGES) {
|
|
ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
|
|
GFP_KERNEL);
|
|
if (!ctx->ring_pages) {
|
|
put_aio_ring_file(ctx);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < nr_pages; i++) {
|
|
struct page *page;
|
|
page = find_or_create_page(file->f_inode->i_mapping,
|
|
i, GFP_HIGHUSER | __GFP_ZERO);
|
|
if (!page)
|
|
break;
|
|
pr_debug("pid(%d) page[%d]->count=%d\n",
|
|
current->pid, i, page_count(page));
|
|
SetPageUptodate(page);
|
|
SetPageDirty(page);
|
|
unlock_page(page);
|
|
|
|
ctx->ring_pages[i] = page;
|
|
}
|
|
ctx->nr_pages = i;
|
|
|
|
if (unlikely(i != nr_pages)) {
|
|
aio_free_ring(ctx);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
ctx->mmap_size = nr_pages * PAGE_SIZE;
|
|
pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
|
|
|
|
down_write(&mm->mmap_sem);
|
|
ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size,
|
|
PROT_READ | PROT_WRITE,
|
|
MAP_SHARED, 0, &unused);
|
|
up_write(&mm->mmap_sem);
|
|
if (IS_ERR((void *)ctx->mmap_base)) {
|
|
ctx->mmap_size = 0;
|
|
aio_free_ring(ctx);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
|
|
|
|
ctx->user_id = ctx->mmap_base;
|
|
ctx->nr_events = nr_events; /* trusted copy */
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
ring->nr = nr_events; /* user copy */
|
|
ring->id = ~0U;
|
|
ring->head = ring->tail = 0;
|
|
ring->magic = AIO_RING_MAGIC;
|
|
ring->compat_features = AIO_RING_COMPAT_FEATURES;
|
|
ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
|
|
ring->header_length = sizeof(struct aio_ring);
|
|
kunmap_atomic(ring);
|
|
flush_dcache_page(ctx->ring_pages[0]);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
|
|
#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
|
|
#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
|
|
|
|
void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel)
|
|
{
|
|
struct kioctx *ctx = req->ki_ctx;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags);
|
|
|
|
if (!req->ki_list.next)
|
|
list_add(&req->ki_list, &ctx->active_reqs);
|
|
|
|
req->ki_cancel = cancel;
|
|
|
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(kiocb_set_cancel_fn);
|
|
|
|
static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb)
|
|
{
|
|
kiocb_cancel_fn *old, *cancel;
|
|
|
|
/*
|
|
* Don't want to set kiocb->ki_cancel = KIOCB_CANCELLED unless it
|
|
* actually has a cancel function, hence the cmpxchg()
|
|
*/
|
|
|
|
cancel = ACCESS_ONCE(kiocb->ki_cancel);
|
|
do {
|
|
if (!cancel || cancel == KIOCB_CANCELLED)
|
|
return -EINVAL;
|
|
|
|
old = cancel;
|
|
cancel = cmpxchg(&kiocb->ki_cancel, old, KIOCB_CANCELLED);
|
|
} while (cancel != old);
|
|
|
|
return cancel(kiocb);
|
|
}
|
|
|
|
static void free_ioctx(struct work_struct *work)
|
|
{
|
|
struct kioctx *ctx = container_of(work, struct kioctx, free_work);
|
|
|
|
pr_debug("freeing %p\n", ctx);
|
|
|
|
aio_free_ring(ctx);
|
|
free_percpu(ctx->cpu);
|
|
kmem_cache_free(kioctx_cachep, ctx);
|
|
}
|
|
|
|
static void free_ioctx_reqs(struct percpu_ref *ref)
|
|
{
|
|
struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
|
|
|
|
INIT_WORK(&ctx->free_work, free_ioctx);
|
|
schedule_work(&ctx->free_work);
|
|
}
|
|
|
|
/*
|
|
* When this function runs, the kioctx has been removed from the "hash table"
|
|
* and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
|
|
* now it's safe to cancel any that need to be.
|
|
*/
|
|
static void free_ioctx_users(struct percpu_ref *ref)
|
|
{
|
|
struct kioctx *ctx = container_of(ref, struct kioctx, users);
|
|
struct kiocb *req;
|
|
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
|
|
while (!list_empty(&ctx->active_reqs)) {
|
|
req = list_first_entry(&ctx->active_reqs,
|
|
struct kiocb, ki_list);
|
|
|
|
list_del_init(&req->ki_list);
|
|
kiocb_cancel(ctx, req);
|
|
}
|
|
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
percpu_ref_kill(&ctx->reqs);
|
|
percpu_ref_put(&ctx->reqs);
|
|
}
|
|
|
|
static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
|
|
{
|
|
unsigned i, new_nr;
|
|
struct kioctx_table *table, *old;
|
|
struct aio_ring *ring;
|
|
|
|
spin_lock(&mm->ioctx_lock);
|
|
rcu_read_lock();
|
|
table = rcu_dereference(mm->ioctx_table);
|
|
|
|
while (1) {
|
|
if (table)
|
|
for (i = 0; i < table->nr; i++)
|
|
if (!table->table[i]) {
|
|
ctx->id = i;
|
|
table->table[i] = ctx;
|
|
rcu_read_unlock();
|
|
spin_unlock(&mm->ioctx_lock);
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
ring->id = ctx->id;
|
|
kunmap_atomic(ring);
|
|
return 0;
|
|
}
|
|
|
|
new_nr = (table ? table->nr : 1) * 4;
|
|
|
|
rcu_read_unlock();
|
|
spin_unlock(&mm->ioctx_lock);
|
|
|
|
table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) *
|
|
new_nr, GFP_KERNEL);
|
|
if (!table)
|
|
return -ENOMEM;
|
|
|
|
table->nr = new_nr;
|
|
|
|
spin_lock(&mm->ioctx_lock);
|
|
rcu_read_lock();
|
|
old = rcu_dereference(mm->ioctx_table);
|
|
|
|
if (!old) {
|
|
rcu_assign_pointer(mm->ioctx_table, table);
|
|
} else if (table->nr > old->nr) {
|
|
memcpy(table->table, old->table,
|
|
old->nr * sizeof(struct kioctx *));
|
|
|
|
rcu_assign_pointer(mm->ioctx_table, table);
|
|
kfree_rcu(old, rcu);
|
|
} else {
|
|
kfree(table);
|
|
table = old;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void aio_nr_sub(unsigned nr)
|
|
{
|
|
spin_lock(&aio_nr_lock);
|
|
if (WARN_ON(aio_nr - nr > aio_nr))
|
|
aio_nr = 0;
|
|
else
|
|
aio_nr -= nr;
|
|
spin_unlock(&aio_nr_lock);
|
|
}
|
|
|
|
/* ioctx_alloc
|
|
* Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
|
|
*/
|
|
static struct kioctx *ioctx_alloc(unsigned nr_events)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct kioctx *ctx;
|
|
int err = -ENOMEM;
|
|
|
|
/*
|
|
* We keep track of the number of available ringbuffer slots, to prevent
|
|
* overflow (reqs_available), and we also use percpu counters for this.
|
|
*
|
|
* So since up to half the slots might be on other cpu's percpu counters
|
|
* and unavailable, double nr_events so userspace sees what they
|
|
* expected: additionally, we move req_batch slots to/from percpu
|
|
* counters at a time, so make sure that isn't 0:
|
|
*/
|
|
nr_events = max(nr_events, num_possible_cpus() * 4);
|
|
nr_events *= 2;
|
|
|
|
/* Prevent overflows */
|
|
if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
|
|
(nr_events > (0x10000000U / sizeof(struct kiocb)))) {
|
|
pr_debug("ENOMEM: nr_events too high\n");
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
if (!nr_events || (unsigned long)nr_events > (aio_max_nr * 2UL))
|
|
return ERR_PTR(-EAGAIN);
|
|
|
|
ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
|
|
if (!ctx)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
ctx->max_reqs = nr_events;
|
|
|
|
if (percpu_ref_init(&ctx->users, free_ioctx_users))
|
|
goto err;
|
|
|
|
if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs))
|
|
goto err;
|
|
|
|
spin_lock_init(&ctx->ctx_lock);
|
|
spin_lock_init(&ctx->completion_lock);
|
|
mutex_init(&ctx->ring_lock);
|
|
init_waitqueue_head(&ctx->wait);
|
|
|
|
INIT_LIST_HEAD(&ctx->active_reqs);
|
|
|
|
ctx->cpu = alloc_percpu(struct kioctx_cpu);
|
|
if (!ctx->cpu)
|
|
goto err;
|
|
|
|
if (aio_setup_ring(ctx) < 0)
|
|
goto err;
|
|
|
|
atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
|
|
ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
|
|
if (ctx->req_batch < 1)
|
|
ctx->req_batch = 1;
|
|
|
|
/* limit the number of system wide aios */
|
|
spin_lock(&aio_nr_lock);
|
|
if (aio_nr + nr_events > (aio_max_nr * 2UL) ||
|
|
aio_nr + nr_events < aio_nr) {
|
|
spin_unlock(&aio_nr_lock);
|
|
err = -EAGAIN;
|
|
goto err_ctx;
|
|
}
|
|
aio_nr += ctx->max_reqs;
|
|
spin_unlock(&aio_nr_lock);
|
|
|
|
percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
|
|
percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
|
|
|
|
err = ioctx_add_table(ctx, mm);
|
|
if (err)
|
|
goto err_cleanup;
|
|
|
|
pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
|
|
ctx, ctx->user_id, mm, ctx->nr_events);
|
|
return ctx;
|
|
|
|
err_cleanup:
|
|
aio_nr_sub(ctx->max_reqs);
|
|
err_ctx:
|
|
aio_free_ring(ctx);
|
|
err:
|
|
free_percpu(ctx->cpu);
|
|
free_percpu(ctx->reqs.pcpu_count);
|
|
free_percpu(ctx->users.pcpu_count);
|
|
kmem_cache_free(kioctx_cachep, ctx);
|
|
pr_debug("error allocating ioctx %d\n", err);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
/* kill_ioctx
|
|
* Cancels all outstanding aio requests on an aio context. Used
|
|
* when the processes owning a context have all exited to encourage
|
|
* the rapid destruction of the kioctx.
|
|
*/
|
|
static void kill_ioctx(struct mm_struct *mm, struct kioctx *ctx)
|
|
{
|
|
if (!atomic_xchg(&ctx->dead, 1)) {
|
|
struct kioctx_table *table;
|
|
|
|
spin_lock(&mm->ioctx_lock);
|
|
rcu_read_lock();
|
|
table = rcu_dereference(mm->ioctx_table);
|
|
|
|
WARN_ON(ctx != table->table[ctx->id]);
|
|
table->table[ctx->id] = NULL;
|
|
rcu_read_unlock();
|
|
spin_unlock(&mm->ioctx_lock);
|
|
|
|
/* percpu_ref_kill() will do the necessary call_rcu() */
|
|
wake_up_all(&ctx->wait);
|
|
|
|
/*
|
|
* It'd be more correct to do this in free_ioctx(), after all
|
|
* the outstanding kiocbs have finished - but by then io_destroy
|
|
* has already returned, so io_setup() could potentially return
|
|
* -EAGAIN with no ioctxs actually in use (as far as userspace
|
|
* could tell).
|
|
*/
|
|
aio_nr_sub(ctx->max_reqs);
|
|
|
|
if (ctx->mmap_size)
|
|
vm_munmap(ctx->mmap_base, ctx->mmap_size);
|
|
|
|
percpu_ref_kill(&ctx->users);
|
|
}
|
|
}
|
|
|
|
/* wait_on_sync_kiocb:
|
|
* Waits on the given sync kiocb to complete.
|
|
*/
|
|
ssize_t wait_on_sync_kiocb(struct kiocb *req)
|
|
{
|
|
while (!req->ki_ctx) {
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
if (req->ki_ctx)
|
|
break;
|
|
io_schedule();
|
|
}
|
|
__set_current_state(TASK_RUNNING);
|
|
return req->ki_user_data;
|
|
}
|
|
EXPORT_SYMBOL(wait_on_sync_kiocb);
|
|
|
|
/*
|
|
* exit_aio: called when the last user of mm goes away. At this point, there is
|
|
* no way for any new requests to be submited or any of the io_* syscalls to be
|
|
* called on the context.
|
|
*
|
|
* There may be outstanding kiocbs, but free_ioctx() will explicitly wait on
|
|
* them.
|
|
*/
|
|
void exit_aio(struct mm_struct *mm)
|
|
{
|
|
struct kioctx_table *table;
|
|
struct kioctx *ctx;
|
|
unsigned i = 0;
|
|
|
|
while (1) {
|
|
rcu_read_lock();
|
|
table = rcu_dereference(mm->ioctx_table);
|
|
|
|
do {
|
|
if (!table || i >= table->nr) {
|
|
rcu_read_unlock();
|
|
rcu_assign_pointer(mm->ioctx_table, NULL);
|
|
if (table)
|
|
kfree(table);
|
|
return;
|
|
}
|
|
|
|
ctx = table->table[i++];
|
|
} while (!ctx);
|
|
|
|
rcu_read_unlock();
|
|
|
|
/*
|
|
* We don't need to bother with munmap() here -
|
|
* exit_mmap(mm) is coming and it'll unmap everything.
|
|
* Since aio_free_ring() uses non-zero ->mmap_size
|
|
* as indicator that it needs to unmap the area,
|
|
* just set it to 0; aio_free_ring() is the only
|
|
* place that uses ->mmap_size, so it's safe.
|
|
*/
|
|
ctx->mmap_size = 0;
|
|
|
|
kill_ioctx(mm, ctx);
|
|
}
|
|
}
|
|
|
|
static void put_reqs_available(struct kioctx *ctx, unsigned nr)
|
|
{
|
|
struct kioctx_cpu *kcpu;
|
|
|
|
preempt_disable();
|
|
kcpu = this_cpu_ptr(ctx->cpu);
|
|
|
|
kcpu->reqs_available += nr;
|
|
while (kcpu->reqs_available >= ctx->req_batch * 2) {
|
|
kcpu->reqs_available -= ctx->req_batch;
|
|
atomic_add(ctx->req_batch, &ctx->reqs_available);
|
|
}
|
|
|
|
preempt_enable();
|
|
}
|
|
|
|
static bool get_reqs_available(struct kioctx *ctx)
|
|
{
|
|
struct kioctx_cpu *kcpu;
|
|
bool ret = false;
|
|
|
|
preempt_disable();
|
|
kcpu = this_cpu_ptr(ctx->cpu);
|
|
|
|
if (!kcpu->reqs_available) {
|
|
int old, avail = atomic_read(&ctx->reqs_available);
|
|
|
|
do {
|
|
if (avail < ctx->req_batch)
|
|
goto out;
|
|
|
|
old = avail;
|
|
avail = atomic_cmpxchg(&ctx->reqs_available,
|
|
avail, avail - ctx->req_batch);
|
|
} while (avail != old);
|
|
|
|
kcpu->reqs_available += ctx->req_batch;
|
|
}
|
|
|
|
ret = true;
|
|
kcpu->reqs_available--;
|
|
out:
|
|
preempt_enable();
|
|
return ret;
|
|
}
|
|
|
|
/* aio_get_req
|
|
* Allocate a slot for an aio request.
|
|
* Returns NULL if no requests are free.
|
|
*/
|
|
static inline struct kiocb *aio_get_req(struct kioctx *ctx)
|
|
{
|
|
struct kiocb *req;
|
|
|
|
if (!get_reqs_available(ctx))
|
|
return NULL;
|
|
|
|
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO);
|
|
if (unlikely(!req))
|
|
goto out_put;
|
|
|
|
percpu_ref_get(&ctx->reqs);
|
|
|
|
req->ki_ctx = ctx;
|
|
return req;
|
|
out_put:
|
|
put_reqs_available(ctx, 1);
|
|
return NULL;
|
|
}
|
|
|
|
static void kiocb_free(struct kiocb *req)
|
|
{
|
|
if (req->ki_filp)
|
|
fput(req->ki_filp);
|
|
if (req->ki_eventfd != NULL)
|
|
eventfd_ctx_put(req->ki_eventfd);
|
|
kmem_cache_free(kiocb_cachep, req);
|
|
}
|
|
|
|
static struct kioctx *lookup_ioctx(unsigned long ctx_id)
|
|
{
|
|
struct aio_ring __user *ring = (void __user *)ctx_id;
|
|
struct mm_struct *mm = current->mm;
|
|
struct kioctx *ctx, *ret = NULL;
|
|
struct kioctx_table *table;
|
|
unsigned id;
|
|
|
|
if (get_user(id, &ring->id))
|
|
return NULL;
|
|
|
|
rcu_read_lock();
|
|
table = rcu_dereference(mm->ioctx_table);
|
|
|
|
if (!table || id >= table->nr)
|
|
goto out;
|
|
|
|
ctx = table->table[id];
|
|
if (ctx && ctx->user_id == ctx_id) {
|
|
percpu_ref_get(&ctx->users);
|
|
ret = ctx;
|
|
}
|
|
out:
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
|
|
/* aio_complete
|
|
* Called when the io request on the given iocb is complete.
|
|
*/
|
|
void aio_complete(struct kiocb *iocb, long res, long res2)
|
|
{
|
|
struct kioctx *ctx = iocb->ki_ctx;
|
|
struct aio_ring *ring;
|
|
struct io_event *ev_page, *event;
|
|
unsigned long flags;
|
|
unsigned tail, pos;
|
|
|
|
/*
|
|
* Special case handling for sync iocbs:
|
|
* - events go directly into the iocb for fast handling
|
|
* - the sync task with the iocb in its stack holds the single iocb
|
|
* ref, no other paths have a way to get another ref
|
|
* - the sync task helpfully left a reference to itself in the iocb
|
|
*/
|
|
if (is_sync_kiocb(iocb)) {
|
|
iocb->ki_user_data = res;
|
|
smp_wmb();
|
|
iocb->ki_ctx = ERR_PTR(-EXDEV);
|
|
wake_up_process(iocb->ki_obj.tsk);
|
|
return;
|
|
}
|
|
|
|
if (iocb->ki_list.next) {
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags);
|
|
list_del(&iocb->ki_list);
|
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
|
|
}
|
|
|
|
/*
|
|
* Add a completion event to the ring buffer. Must be done holding
|
|
* ctx->completion_lock to prevent other code from messing with the tail
|
|
* pointer since we might be called from irq context.
|
|
*/
|
|
spin_lock_irqsave(&ctx->completion_lock, flags);
|
|
|
|
tail = ctx->tail;
|
|
pos = tail + AIO_EVENTS_OFFSET;
|
|
|
|
if (++tail >= ctx->nr_events)
|
|
tail = 0;
|
|
|
|
ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
|
|
event = ev_page + pos % AIO_EVENTS_PER_PAGE;
|
|
|
|
event->obj = (u64)(unsigned long)iocb->ki_obj.user;
|
|
event->data = iocb->ki_user_data;
|
|
event->res = res;
|
|
event->res2 = res2;
|
|
|
|
kunmap_atomic(ev_page);
|
|
flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
|
|
|
|
pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n",
|
|
ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
|
|
res, res2);
|
|
|
|
/* after flagging the request as done, we
|
|
* must never even look at it again
|
|
*/
|
|
smp_wmb(); /* make event visible before updating tail */
|
|
|
|
ctx->tail = tail;
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
ring->tail = tail;
|
|
kunmap_atomic(ring);
|
|
flush_dcache_page(ctx->ring_pages[0]);
|
|
|
|
spin_unlock_irqrestore(&ctx->completion_lock, flags);
|
|
|
|
pr_debug("added to ring %p at [%u]\n", iocb, tail);
|
|
|
|
/*
|
|
* Check if the user asked us to deliver the result through an
|
|
* eventfd. The eventfd_signal() function is safe to be called
|
|
* from IRQ context.
|
|
*/
|
|
if (iocb->ki_eventfd != NULL)
|
|
eventfd_signal(iocb->ki_eventfd, 1);
|
|
|
|
/* everything turned out well, dispose of the aiocb. */
|
|
kiocb_free(iocb);
|
|
|
|
/*
|
|
* We have to order our ring_info tail store above and test
|
|
* of the wait list below outside the wait lock. This is
|
|
* like in wake_up_bit() where clearing a bit has to be
|
|
* ordered with the unlocked test.
|
|
*/
|
|
smp_mb();
|
|
|
|
if (waitqueue_active(&ctx->wait))
|
|
wake_up(&ctx->wait);
|
|
|
|
percpu_ref_put(&ctx->reqs);
|
|
}
|
|
EXPORT_SYMBOL(aio_complete);
|
|
|
|
/* aio_read_events
|
|
* Pull an event off of the ioctx's event ring. Returns the number of
|
|
* events fetched
|
|
*/
|
|
static long aio_read_events_ring(struct kioctx *ctx,
|
|
struct io_event __user *event, long nr)
|
|
{
|
|
struct aio_ring *ring;
|
|
unsigned head, tail, pos;
|
|
long ret = 0;
|
|
int copy_ret;
|
|
|
|
mutex_lock(&ctx->ring_lock);
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
head = ring->head;
|
|
tail = ring->tail;
|
|
kunmap_atomic(ring);
|
|
|
|
pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
|
|
|
|
if (head == tail)
|
|
goto out;
|
|
|
|
while (ret < nr) {
|
|
long avail;
|
|
struct io_event *ev;
|
|
struct page *page;
|
|
|
|
avail = (head <= tail ? tail : ctx->nr_events) - head;
|
|
if (head == tail)
|
|
break;
|
|
|
|
avail = min(avail, nr - ret);
|
|
avail = min_t(long, avail, AIO_EVENTS_PER_PAGE -
|
|
((head + AIO_EVENTS_OFFSET) % AIO_EVENTS_PER_PAGE));
|
|
|
|
pos = head + AIO_EVENTS_OFFSET;
|
|
page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
|
|
pos %= AIO_EVENTS_PER_PAGE;
|
|
|
|
ev = kmap(page);
|
|
copy_ret = copy_to_user(event + ret, ev + pos,
|
|
sizeof(*ev) * avail);
|
|
kunmap(page);
|
|
|
|
if (unlikely(copy_ret)) {
|
|
ret = -EFAULT;
|
|
goto out;
|
|
}
|
|
|
|
ret += avail;
|
|
head += avail;
|
|
head %= ctx->nr_events;
|
|
}
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
ring->head = head;
|
|
kunmap_atomic(ring);
|
|
flush_dcache_page(ctx->ring_pages[0]);
|
|
|
|
pr_debug("%li h%u t%u\n", ret, head, tail);
|
|
|
|
put_reqs_available(ctx, ret);
|
|
out:
|
|
mutex_unlock(&ctx->ring_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,
|
|
struct io_event __user *event, long *i)
|
|
{
|
|
long ret = aio_read_events_ring(ctx, event + *i, nr - *i);
|
|
|
|
if (ret > 0)
|
|
*i += ret;
|
|
|
|
if (unlikely(atomic_read(&ctx->dead)))
|
|
ret = -EINVAL;
|
|
|
|
if (!*i)
|
|
*i = ret;
|
|
|
|
return ret < 0 || *i >= min_nr;
|
|
}
|
|
|
|
static long read_events(struct kioctx *ctx, long min_nr, long nr,
|
|
struct io_event __user *event,
|
|
struct timespec __user *timeout)
|
|
{
|
|
ktime_t until = { .tv64 = KTIME_MAX };
|
|
long ret = 0;
|
|
|
|
if (timeout) {
|
|
struct timespec ts;
|
|
|
|
if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
|
|
return -EFAULT;
|
|
|
|
until = timespec_to_ktime(ts);
|
|
}
|
|
|
|
/*
|
|
* Note that aio_read_events() is being called as the conditional - i.e.
|
|
* we're calling it after prepare_to_wait() has set task state to
|
|
* TASK_INTERRUPTIBLE.
|
|
*
|
|
* But aio_read_events() can block, and if it blocks it's going to flip
|
|
* the task state back to TASK_RUNNING.
|
|
*
|
|
* This should be ok, provided it doesn't flip the state back to
|
|
* TASK_RUNNING and return 0 too much - that causes us to spin. That
|
|
* will only happen if the mutex_lock() call blocks, and we then find
|
|
* the ringbuffer empty. So in practice we should be ok, but it's
|
|
* something to be aware of when touching this code.
|
|
*/
|
|
wait_event_interruptible_hrtimeout(ctx->wait,
|
|
aio_read_events(ctx, min_nr, nr, event, &ret), until);
|
|
|
|
if (!ret && signal_pending(current))
|
|
ret = -EINTR;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* sys_io_setup:
|
|
* Create an aio_context capable of receiving at least nr_events.
|
|
* ctxp must not point to an aio_context that already exists, and
|
|
* must be initialized to 0 prior to the call. On successful
|
|
* creation of the aio_context, *ctxp is filled in with the resulting
|
|
* handle. May fail with -EINVAL if *ctxp is not initialized,
|
|
* if the specified nr_events exceeds internal limits. May fail
|
|
* with -EAGAIN if the specified nr_events exceeds the user's limit
|
|
* of available events. May fail with -ENOMEM if insufficient kernel
|
|
* resources are available. May fail with -EFAULT if an invalid
|
|
* pointer is passed for ctxp. Will fail with -ENOSYS if not
|
|
* implemented.
|
|
*/
|
|
SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
|
|
{
|
|
struct kioctx *ioctx = NULL;
|
|
unsigned long ctx;
|
|
long ret;
|
|
|
|
ret = get_user(ctx, ctxp);
|
|
if (unlikely(ret))
|
|
goto out;
|
|
|
|
ret = -EINVAL;
|
|
if (unlikely(ctx || nr_events == 0)) {
|
|
pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
|
|
ctx, nr_events);
|
|
goto out;
|
|
}
|
|
|
|
ioctx = ioctx_alloc(nr_events);
|
|
ret = PTR_ERR(ioctx);
|
|
if (!IS_ERR(ioctx)) {
|
|
ret = put_user(ioctx->user_id, ctxp);
|
|
if (ret)
|
|
kill_ioctx(current->mm, ioctx);
|
|
percpu_ref_put(&ioctx->users);
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/* sys_io_destroy:
|
|
* Destroy the aio_context specified. May cancel any outstanding
|
|
* AIOs and block on completion. Will fail with -ENOSYS if not
|
|
* implemented. May fail with -EINVAL if the context pointed to
|
|
* is invalid.
|
|
*/
|
|
SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
|
|
{
|
|
struct kioctx *ioctx = lookup_ioctx(ctx);
|
|
if (likely(NULL != ioctx)) {
|
|
kill_ioctx(current->mm, ioctx);
|
|
percpu_ref_put(&ioctx->users);
|
|
return 0;
|
|
}
|
|
pr_debug("EINVAL: io_destroy: invalid context id\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
typedef ssize_t (aio_rw_op)(struct kiocb *, const struct iovec *,
|
|
unsigned long, loff_t);
|
|
|
|
static ssize_t aio_setup_vectored_rw(struct kiocb *kiocb,
|
|
int rw, char __user *buf,
|
|
unsigned long *nr_segs,
|
|
struct iovec **iovec,
|
|
bool compat)
|
|
{
|
|
ssize_t ret;
|
|
|
|
*nr_segs = kiocb->ki_nbytes;
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
if (compat)
|
|
ret = compat_rw_copy_check_uvector(rw,
|
|
(struct compat_iovec __user *)buf,
|
|
*nr_segs, 1, *iovec, iovec);
|
|
else
|
|
#endif
|
|
ret = rw_copy_check_uvector(rw,
|
|
(struct iovec __user *)buf,
|
|
*nr_segs, 1, *iovec, iovec);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
/* ki_nbytes now reflect bytes instead of segs */
|
|
kiocb->ki_nbytes = ret;
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t aio_setup_single_vector(struct kiocb *kiocb,
|
|
int rw, char __user *buf,
|
|
unsigned long *nr_segs,
|
|
struct iovec *iovec)
|
|
{
|
|
if (unlikely(!access_ok(!rw, buf, kiocb->ki_nbytes)))
|
|
return -EFAULT;
|
|
|
|
iovec->iov_base = buf;
|
|
iovec->iov_len = kiocb->ki_nbytes;
|
|
*nr_segs = 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* aio_setup_iocb:
|
|
* Performs the initial checks and aio retry method
|
|
* setup for the kiocb at the time of io submission.
|
|
*/
|
|
static ssize_t aio_run_iocb(struct kiocb *req, unsigned opcode,
|
|
char __user *buf, bool compat)
|
|
{
|
|
struct file *file = req->ki_filp;
|
|
ssize_t ret;
|
|
unsigned long nr_segs;
|
|
int rw;
|
|
fmode_t mode;
|
|
aio_rw_op *rw_op;
|
|
struct iovec inline_vec, *iovec = &inline_vec;
|
|
|
|
switch (opcode) {
|
|
case IOCB_CMD_PREAD:
|
|
case IOCB_CMD_PREADV:
|
|
mode = FMODE_READ;
|
|
rw = READ;
|
|
rw_op = file->f_op->aio_read;
|
|
goto rw_common;
|
|
|
|
case IOCB_CMD_PWRITE:
|
|
case IOCB_CMD_PWRITEV:
|
|
mode = FMODE_WRITE;
|
|
rw = WRITE;
|
|
rw_op = file->f_op->aio_write;
|
|
goto rw_common;
|
|
rw_common:
|
|
if (unlikely(!(file->f_mode & mode)))
|
|
return -EBADF;
|
|
|
|
if (!rw_op)
|
|
return -EINVAL;
|
|
|
|
ret = (opcode == IOCB_CMD_PREADV ||
|
|
opcode == IOCB_CMD_PWRITEV)
|
|
? aio_setup_vectored_rw(req, rw, buf, &nr_segs,
|
|
&iovec, compat)
|
|
: aio_setup_single_vector(req, rw, buf, &nr_segs,
|
|
iovec);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = rw_verify_area(rw, file, &req->ki_pos, req->ki_nbytes);
|
|
if (ret < 0) {
|
|
if (iovec != &inline_vec)
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
|
|
req->ki_nbytes = ret;
|
|
|
|
/* XXX: move/kill - rw_verify_area()? */
|
|
/* This matches the pread()/pwrite() logic */
|
|
if (req->ki_pos < 0) {
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
if (rw == WRITE)
|
|
file_start_write(file);
|
|
|
|
ret = rw_op(req, iovec, nr_segs, req->ki_pos);
|
|
|
|
if (rw == WRITE)
|
|
file_end_write(file);
|
|
break;
|
|
|
|
case IOCB_CMD_FDSYNC:
|
|
if (!file->f_op->aio_fsync)
|
|
return -EINVAL;
|
|
|
|
ret = file->f_op->aio_fsync(req, 1);
|
|
break;
|
|
|
|
case IOCB_CMD_FSYNC:
|
|
if (!file->f_op->aio_fsync)
|
|
return -EINVAL;
|
|
|
|
ret = file->f_op->aio_fsync(req, 0);
|
|
break;
|
|
|
|
default:
|
|
pr_debug("EINVAL: no operation provided\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (iovec != &inline_vec)
|
|
kfree(iovec);
|
|
|
|
if (ret != -EIOCBQUEUED) {
|
|
/*
|
|
* There's no easy way to restart the syscall since other AIO's
|
|
* may be already running. Just fail this IO with EINTR.
|
|
*/
|
|
if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR ||
|
|
ret == -ERESTARTNOHAND ||
|
|
ret == -ERESTART_RESTARTBLOCK))
|
|
ret = -EINTR;
|
|
aio_complete(req, ret, 0);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
|
|
struct iocb *iocb, bool compat)
|
|
{
|
|
struct kiocb *req;
|
|
ssize_t ret;
|
|
|
|
/* enforce forwards compatibility on users */
|
|
if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
|
|
pr_debug("EINVAL: reserve field set\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* prevent overflows */
|
|
if (unlikely(
|
|
(iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
|
|
(iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
|
|
((ssize_t)iocb->aio_nbytes < 0)
|
|
)) {
|
|
pr_debug("EINVAL: io_submit: overflow check\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
req = aio_get_req(ctx);
|
|
if (unlikely(!req))
|
|
return -EAGAIN;
|
|
|
|
req->ki_filp = fget(iocb->aio_fildes);
|
|
if (unlikely(!req->ki_filp)) {
|
|
ret = -EBADF;
|
|
goto out_put_req;
|
|
}
|
|
|
|
if (iocb->aio_flags & IOCB_FLAG_RESFD) {
|
|
/*
|
|
* If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
|
|
* instance of the file* now. The file descriptor must be
|
|
* an eventfd() fd, and will be signaled for each completed
|
|
* event using the eventfd_signal() function.
|
|
*/
|
|
req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
|
|
if (IS_ERR(req->ki_eventfd)) {
|
|
ret = PTR_ERR(req->ki_eventfd);
|
|
req->ki_eventfd = NULL;
|
|
goto out_put_req;
|
|
}
|
|
}
|
|
|
|
ret = put_user(KIOCB_KEY, &user_iocb->aio_key);
|
|
if (unlikely(ret)) {
|
|
pr_debug("EFAULT: aio_key\n");
|
|
goto out_put_req;
|
|
}
|
|
|
|
req->ki_obj.user = user_iocb;
|
|
req->ki_user_data = iocb->aio_data;
|
|
req->ki_pos = iocb->aio_offset;
|
|
req->ki_nbytes = iocb->aio_nbytes;
|
|
|
|
ret = aio_run_iocb(req, iocb->aio_lio_opcode,
|
|
(char __user *)(unsigned long)iocb->aio_buf,
|
|
compat);
|
|
if (ret)
|
|
goto out_put_req;
|
|
|
|
return 0;
|
|
out_put_req:
|
|
put_reqs_available(ctx, 1);
|
|
percpu_ref_put(&ctx->reqs);
|
|
kiocb_free(req);
|
|
return ret;
|
|
}
|
|
|
|
long do_io_submit(aio_context_t ctx_id, long nr,
|
|
struct iocb __user *__user *iocbpp, bool compat)
|
|
{
|
|
struct kioctx *ctx;
|
|
long ret = 0;
|
|
int i = 0;
|
|
struct blk_plug plug;
|
|
|
|
if (unlikely(nr < 0))
|
|
return -EINVAL;
|
|
|
|
if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
|
|
nr = LONG_MAX/sizeof(*iocbpp);
|
|
|
|
if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
|
|
return -EFAULT;
|
|
|
|
ctx = lookup_ioctx(ctx_id);
|
|
if (unlikely(!ctx)) {
|
|
pr_debug("EINVAL: invalid context id\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
blk_start_plug(&plug);
|
|
|
|
/*
|
|
* AKPM: should this return a partial result if some of the IOs were
|
|
* successfully submitted?
|
|
*/
|
|
for (i=0; i<nr; i++) {
|
|
struct iocb __user *user_iocb;
|
|
struct iocb tmp;
|
|
|
|
if (unlikely(__get_user(user_iocb, iocbpp + i))) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
ret = io_submit_one(ctx, user_iocb, &tmp, compat);
|
|
if (ret)
|
|
break;
|
|
}
|
|
blk_finish_plug(&plug);
|
|
|
|
percpu_ref_put(&ctx->users);
|
|
return i ? i : ret;
|
|
}
|
|
|
|
/* sys_io_submit:
|
|
* Queue the nr iocbs pointed to by iocbpp for processing. Returns
|
|
* the number of iocbs queued. May return -EINVAL if the aio_context
|
|
* specified by ctx_id is invalid, if nr is < 0, if the iocb at
|
|
* *iocbpp[0] is not properly initialized, if the operation specified
|
|
* is invalid for the file descriptor in the iocb. May fail with
|
|
* -EFAULT if any of the data structures point to invalid data. May
|
|
* fail with -EBADF if the file descriptor specified in the first
|
|
* iocb is invalid. May fail with -EAGAIN if insufficient resources
|
|
* are available to queue any iocbs. Will return 0 if nr is 0. Will
|
|
* fail with -ENOSYS if not implemented.
|
|
*/
|
|
SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
|
|
struct iocb __user * __user *, iocbpp)
|
|
{
|
|
return do_io_submit(ctx_id, nr, iocbpp, 0);
|
|
}
|
|
|
|
/* lookup_kiocb
|
|
* Finds a given iocb for cancellation.
|
|
*/
|
|
static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
|
|
u32 key)
|
|
{
|
|
struct list_head *pos;
|
|
|
|
assert_spin_locked(&ctx->ctx_lock);
|
|
|
|
if (key != KIOCB_KEY)
|
|
return NULL;
|
|
|
|
/* TODO: use a hash or array, this sucks. */
|
|
list_for_each(pos, &ctx->active_reqs) {
|
|
struct kiocb *kiocb = list_kiocb(pos);
|
|
if (kiocb->ki_obj.user == iocb)
|
|
return kiocb;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/* sys_io_cancel:
|
|
* Attempts to cancel an iocb previously passed to io_submit. If
|
|
* the operation is successfully cancelled, the resulting event is
|
|
* copied into the memory pointed to by result without being placed
|
|
* into the completion queue and 0 is returned. May fail with
|
|
* -EFAULT if any of the data structures pointed to are invalid.
|
|
* May fail with -EINVAL if aio_context specified by ctx_id is
|
|
* invalid. May fail with -EAGAIN if the iocb specified was not
|
|
* cancelled. Will fail with -ENOSYS if not implemented.
|
|
*/
|
|
SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
|
|
struct io_event __user *, result)
|
|
{
|
|
struct kioctx *ctx;
|
|
struct kiocb *kiocb;
|
|
u32 key;
|
|
int ret;
|
|
|
|
ret = get_user(key, &iocb->aio_key);
|
|
if (unlikely(ret))
|
|
return -EFAULT;
|
|
|
|
ctx = lookup_ioctx(ctx_id);
|
|
if (unlikely(!ctx))
|
|
return -EINVAL;
|
|
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
|
|
kiocb = lookup_kiocb(ctx, iocb, key);
|
|
if (kiocb)
|
|
ret = kiocb_cancel(ctx, kiocb);
|
|
else
|
|
ret = -EINVAL;
|
|
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
if (!ret) {
|
|
/*
|
|
* The result argument is no longer used - the io_event is
|
|
* always delivered via the ring buffer. -EINPROGRESS indicates
|
|
* cancellation is progress:
|
|
*/
|
|
ret = -EINPROGRESS;
|
|
}
|
|
|
|
percpu_ref_put(&ctx->users);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* io_getevents:
|
|
* Attempts to read at least min_nr events and up to nr events from
|
|
* the completion queue for the aio_context specified by ctx_id. If
|
|
* it succeeds, the number of read events is returned. May fail with
|
|
* -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
|
|
* out of range, if timeout is out of range. May fail with -EFAULT
|
|
* if any of the memory specified is invalid. May return 0 or
|
|
* < min_nr if the timeout specified by timeout has elapsed
|
|
* before sufficient events are available, where timeout == NULL
|
|
* specifies an infinite timeout. Note that the timeout pointed to by
|
|
* timeout is relative. Will fail with -ENOSYS if not implemented.
|
|
*/
|
|
SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
|
|
long, min_nr,
|
|
long, nr,
|
|
struct io_event __user *, events,
|
|
struct timespec __user *, timeout)
|
|
{
|
|
struct kioctx *ioctx = lookup_ioctx(ctx_id);
|
|
long ret = -EINVAL;
|
|
|
|
if (likely(ioctx)) {
|
|
if (likely(min_nr <= nr && min_nr >= 0))
|
|
ret = read_events(ioctx, min_nr, nr, events, timeout);
|
|
percpu_ref_put(&ioctx->users);
|
|
}
|
|
return ret;
|
|
}
|