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authorSteven Rostedt <rostedt@goodmis.org>2009-09-18 13:05:42 -0700
committerAl Viro <viro@zeniv.linux.org.uk>2009-09-24 07:47:22 -0400
commit14be27460e4722d7135de3c46d043b4fc4382247 (patch)
treed7026e0e43c1f048f2a0f31a54beb93b91b5fb89 /fs/libfs.c
parent94a8d5caba74211ec76dac80fc6e2d5c391530df (diff)
downloadlinux-linaro-stable-14be27460e4722d7135de3c46d043b4fc4382247.tar.gz
libfs: make simple_read_from_buffer conventional
Impact: have simple_read_from_buffer conform to standards It was brought to my attention by Andrew Morton, Theodore Tso, and H. Peter Anvin that a read from userspace should only return -EFAULT if nothing was actually read. Looking at the simple_read_from_buffer I noticed that this function does not conform to that rule. This patch fixes that function. [akpm@linux-foundation.org: simplification suggested by hpa] [hpa@zytor.com: fix count==0 handling] Signed-off-by: Steven Rostedt <srostedt@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/libfs.c')
-rw-r--r--fs/libfs.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/libfs.c b/fs/libfs.c
index dcec3d3ea64f..662a28e4f667 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -527,14 +527,18 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
const void *from, size_t available)
{
loff_t pos = *ppos;
+ size_t ret;
+
if (pos < 0)
return -EINVAL;
- if (pos >= available)
+ if (pos >= available || !count)
return 0;
if (count > available - pos)
count = available - pos;
- if (copy_to_user(to, from + pos, count))
+ ret = copy_to_user(to, from + pos, count);
+ if (ret == count)
return -EFAULT;
+ count -= ret;
*ppos = pos + count;
return count;
}