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authorAmir Goldstein <amir73il@gmail.com>2019-06-05 18:04:48 +0300
committerDarrick J. Wong <darrick.wong@oracle.com>2019-06-09 20:06:19 +0300
commit646955cd5425dd8fed8205cbb1b4373c222d028e (patch)
treeb05036cc5e7433a38305db3f6910bc7905bc067a /mm/filemap.c
parenta31713517dac0862a3f0ec9006df9160ce022b0c (diff)
downloadlinux-646955cd5425dd8fed8205cbb1b4373c222d028e.tar.xz
vfs: remove redundant checks from generic_remap_checks()
The access limit checks on input file range in generic_remap_checks() are redundant because the input file size is guaranteed to be within limits and pos+len are already checked to be within input file size. Beyond the fact that the check cannot fail, if it would have failed, it could return -EFBIG for input file range error. There is no precedent for that. -EFBIG is returned in syscalls that would change file length. With that call removed, we can fold generic_access_check_limits() into generic_write_check_limits(). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c33
1 files changed, 12 insertions, 21 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index a38619a4a6af..44361928bbb0 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2895,24 +2895,11 @@ EXPORT_SYMBOL(read_cache_page_gfp);
* LFS limits. If pos is under the limit it becomes a short access. If it
* exceeds the limit we return -EFBIG.
*/
-static int generic_access_check_limits(struct file *file, loff_t pos,
- loff_t *count)
-{
- struct inode *inode = file->f_mapping->host;
- loff_t max_size = inode->i_sb->s_maxbytes;
-
- if (!(file->f_flags & O_LARGEFILE))
- max_size = MAX_NON_LFS;
-
- if (unlikely(pos >= max_size))
- return -EFBIG;
- *count = min(*count, max_size - pos);
- return 0;
-}
-
static int generic_write_check_limits(struct file *file, loff_t pos,
loff_t *count)
{
+ struct inode *inode = file->f_mapping->host;
+ loff_t max_size = inode->i_sb->s_maxbytes;
loff_t limit = rlimit(RLIMIT_FSIZE);
if (limit != RLIM_INFINITY) {
@@ -2923,7 +2910,15 @@ static int generic_write_check_limits(struct file *file, loff_t pos,
*count = min(*count, limit - pos);
}
- return generic_access_check_limits(file, pos, count);
+ if (!(file->f_flags & O_LARGEFILE))
+ max_size = MAX_NON_LFS;
+
+ if (unlikely(pos >= max_size))
+ return -EFBIG;
+
+ *count = min(*count, max_size - pos);
+
+ return 0;
}
/*
@@ -2963,7 +2958,7 @@ EXPORT_SYMBOL(generic_write_checks);
/*
* Performs necessary checks before doing a clone.
*
- * Can adjust amount of bytes to clone.
+ * Can adjust amount of bytes to clone via @req_count argument.
* Returns appropriate error code that caller should return or
* zero in case the clone should be allowed.
*/
@@ -3001,10 +2996,6 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in,
return -EINVAL;
count = min(count, size_in - (uint64_t)pos_in);
- ret = generic_access_check_limits(file_in, pos_in, &count);
- if (ret)
- return ret;
-
ret = generic_write_check_limits(file_out, pos_out, &count);
if (ret)
return ret;