5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Keith Busch <kbusch@xxxxxxxxxx>
commit d6fef34ee4d102be448146f24caf96d7b4a05401 upstream.
If the offset equals the bv_len of the first registered bvec, then the
request does not include any of that first bvec. Skip it so that drivers
don't have to deal with a zero length bvec, which was observed to break
NVMe's PRP list creation.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: bd11b3a391e3 ("io_uring: don't use iov_iter_advance() for fixed buffers")
Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231120221831.2646460-1-kbusch@xxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/io_uring.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1256,7 +1256,7 @@ static int io_import_fixed(struct io_rin
*/
const struct bio_vec *bvec = imu->bvec;
- if (offset <= bvec->bv_len) {
+ if (offset < bvec->bv_len) {
iov_iter_advance(iter, offset);
} else {
unsigned long seg_skip;
