mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-30 01:26:44 +07:00
b5beb1caff
I've written some test programs in ltp project. During writing I met an
problem which I cannot solve in user land. So I wrote a patch for linux
kernel. Please, include this patch if acceptable.
The test program tests the 4th parameter of fadvise64_64:
long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice);
My test case calls fadvise64_64 with invalid advice value and checks errno is
set to EINVAL. About the advice parameter man page says:
...
Permissible values for advice include:
POSIX_FADV_NORMAL
...
POSIX_FADV_SEQUENTIAL
...
POSIX_FADV_RANDOM
...
POSIX_FADV_NOREUSE
...
POSIX_FADV_WILLNEED
...
POSIX_FADV_DONTNEED
...
ERRORS
...
EINVAL An invalid value was specified for advice.
However, I got a bug report that the system call invocations
in my test case returned 0 unexpectedly.
I've inspected the kernel code:
asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
{
struct file *file = fget(fd);
struct address_space *mapping;
struct backing_dev_info *bdi;
loff_t endbyte; /* inclusive */
pgoff_t start_index;
pgoff_t end_index;
unsigned long nrpages;
int ret = 0;
if (!file)
return -EBADF;
if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) {
ret = -ESPIPE;
goto out;
}
mapping = file->f_mapping;
if (!mapping || len < 0) {
ret = -EINVAL;
goto out;
}
if (mapping->a_ops->get_xip_page)
/* no bad return value, but ignore advice */
goto out;
...
out:
fput(file);
return ret;
}
I found the advice parameter is just ignored in the case
mapping->a_ops->get_xip_page is given. This behavior is different from
what is written on the man page. Is this o.k.?
get_xip_page is given if CONFIG_EXT2_FS_XIP is true.
Anyway I cannot find the easy way to detect get_xip_page
field is given or CONFIG_EXT2_FS_XIP is true from the
user space.
I propose the following patch which checks the advice parameter
even if get_xip_page is given.
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Acked-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
138 lines
2.9 KiB
C
138 lines
2.9 KiB
C
/*
|
|
* mm/fadvise.c
|
|
*
|
|
* Copyright (C) 2002, Linus Torvalds
|
|
*
|
|
* 11Jan2003 akpm@digeo.com
|
|
* Initial version.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/file.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/pagevec.h>
|
|
#include <linux/fadvise.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/syscalls.h>
|
|
|
|
#include <asm/unistd.h>
|
|
|
|
/*
|
|
* POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
|
|
* deactivate the pages and clear PG_Referenced.
|
|
*/
|
|
asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
|
|
{
|
|
struct file *file = fget(fd);
|
|
struct address_space *mapping;
|
|
struct backing_dev_info *bdi;
|
|
loff_t endbyte; /* inclusive */
|
|
pgoff_t start_index;
|
|
pgoff_t end_index;
|
|
unsigned long nrpages;
|
|
int ret = 0;
|
|
|
|
if (!file)
|
|
return -EBADF;
|
|
|
|
if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) {
|
|
ret = -ESPIPE;
|
|
goto out;
|
|
}
|
|
|
|
mapping = file->f_mapping;
|
|
if (!mapping || len < 0) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (mapping->a_ops->get_xip_page) {
|
|
switch (advice) {
|
|
case POSIX_FADV_NORMAL:
|
|
case POSIX_FADV_RANDOM:
|
|
case POSIX_FADV_SEQUENTIAL:
|
|
case POSIX_FADV_WILLNEED:
|
|
case POSIX_FADV_NOREUSE:
|
|
case POSIX_FADV_DONTNEED:
|
|
/* no bad return value, but ignore advice */
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
}
|
|
goto out;
|
|
}
|
|
|
|
/* Careful about overflows. Len == 0 means "as much as possible" */
|
|
endbyte = offset + len;
|
|
if (!len || endbyte < len)
|
|
endbyte = -1;
|
|
else
|
|
endbyte--; /* inclusive */
|
|
|
|
bdi = mapping->backing_dev_info;
|
|
|
|
switch (advice) {
|
|
case POSIX_FADV_NORMAL:
|
|
file->f_ra.ra_pages = bdi->ra_pages;
|
|
break;
|
|
case POSIX_FADV_RANDOM:
|
|
file->f_ra.ra_pages = 0;
|
|
break;
|
|
case POSIX_FADV_SEQUENTIAL:
|
|
file->f_ra.ra_pages = bdi->ra_pages * 2;
|
|
break;
|
|
case POSIX_FADV_WILLNEED:
|
|
if (!mapping->a_ops->readpage) {
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
/* First and last PARTIAL page! */
|
|
start_index = offset >> PAGE_CACHE_SHIFT;
|
|
end_index = endbyte >> PAGE_CACHE_SHIFT;
|
|
|
|
/* Careful about overflow on the "+1" */
|
|
nrpages = end_index - start_index + 1;
|
|
if (!nrpages)
|
|
nrpages = ~0UL;
|
|
|
|
ret = force_page_cache_readahead(mapping, file,
|
|
start_index,
|
|
max_sane_readahead(nrpages));
|
|
if (ret > 0)
|
|
ret = 0;
|
|
break;
|
|
case POSIX_FADV_NOREUSE:
|
|
break;
|
|
case POSIX_FADV_DONTNEED:
|
|
if (!bdi_write_congested(mapping->backing_dev_info))
|
|
filemap_flush(mapping);
|
|
|
|
/* First and last FULL page! */
|
|
start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
|
|
end_index = (endbyte >> PAGE_CACHE_SHIFT);
|
|
|
|
if (end_index >= start_index)
|
|
invalidate_mapping_pages(mapping, start_index,
|
|
end_index);
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
}
|
|
out:
|
|
fput(file);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_SYS_FADVISE64
|
|
|
|
asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
|
|
{
|
|
return sys_fadvise64_64(fd, offset, len, advice);
|
|
}
|
|
|
|
#endif
|