Fix cifs_limit_bvec_subset() so that it limits the span to the maximum
specified and won't return with a size greater than max_size.
Fixes: d08089f649a0 ("cifs: Change the I/O paths to use an iterator rather than a page list")
Reported-by: Shyam Prasad N <[email protected]>
Signed-off-by: David Howells <[email protected]>
cc: Steve French <[email protected]>
cc: Rohith Surabattula <[email protected]>
cc: Paulo Alcantara <[email protected]>
cc: Tom Talpey <[email protected]>
cc: Jeff Layton <[email protected]>
cc: [email protected]
cc: [email protected]
---
fs/cifs/file.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index ba7f2e09d6c8..4778614cfccf 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3353,6 +3353,7 @@ static size_t cifs_limit_bvec_subset(const struct iov_iter *iter, size_t max_siz
while (n && ix < nbv) {
len = min3(n, bvecs[ix].bv_len - skip, max_size);
span += len;
+ max_size -= len;
nsegs++;
ix++;
if (span >= max_size || nsegs >= max_segs)
On Mon, May 22, 2023 at 8:22 PM David Howells <[email protected]> wrote:
>
> Fix cifs_limit_bvec_subset() so that it limits the span to the maximum
> specified and won't return with a size greater than max_size.
>
> Fixes: d08089f649a0 ("cifs: Change the I/O paths to use an iterator rather than a page list")
> Reported-by: Shyam Prasad N <[email protected]>
> Signed-off-by: David Howells <[email protected]>
> cc: Steve French <[email protected]>
> cc: Rohith Surabattula <[email protected]>
> cc: Paulo Alcantara <[email protected]>
> cc: Tom Talpey <[email protected]>
> cc: Jeff Layton <[email protected]>
> cc: [email protected]
> cc: [email protected]
> ---
> fs/cifs/file.c | 1 +
> 1 file changed, 1 insertion(+)
>
>
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index ba7f2e09d6c8..4778614cfccf 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -3353,6 +3353,7 @@ static size_t cifs_limit_bvec_subset(const struct iov_iter *iter, size_t max_siz
> while (n && ix < nbv) {
> len = min3(n, bvecs[ix].bv_len - skip, max_size);
> span += len;
> + max_size -= len;
Shouldn't this decrement happen below, after the span has been
compared with max_size?
> nsegs++;
> ix++;
> if (span >= max_size || nsegs >= max_segs)
>
--
Regards,
Shyam
Shyam Prasad N <[email protected]> wrote:
> > + max_size -= len;
>
> Shouldn't this decrement happen below, after the span has been
> compared with max_size?
It probably doesn't matter. The compiler is free to move it around, but yes
that and ix++ can both be moved down.
David
On Mon, May 22, 2023 at 1:11 PM David Howells <[email protected]> wrote:
>
> Shyam Prasad N <[email protected]> wrote:
>
> > > + max_size -= len;
> >
> > Shouldn't this decrement happen below, after the span has been
> > compared with max_size?
>
> It probably doesn't matter. The compiler is free to move it around, but yes
> that and ix++ can both be moved down.
I am not sure I follow - can you explain? It looks like moving it up
vs. down would change behavior
--
Thanks,
Steve