io_uring_submit: fix head/tail wrap issue
Use proper unsigned math to figure out how many entries we have. If
we have head and tail on either side of UINT_MAX, then we currently
don't submit anything as:
while (head < tail) {
is never true.
Reported-by: Weiping Zhang
@@ -71,7 +71,7 @@ int io_uring_submit(struct io_uring *ring)
{
struct io_uring_sq *sq = &ring->sq;
const unsigned mask = *sq->kring_mask;
- unsigned ktail, ktail_next, submitted;
+ unsigned ktail, ktail_next, submitted, to_submit;
int ret;
/*
@@ -93,7 +93,8 @@ int io_uring_submit(struct io_uring *ring)
*/
submitted = 0;
ktail = ktail_next = *sq->ktail;
- while (sq->sqe_head < sq->sqe_tail) {
+ to_submit = sq->sqe_tail - sq->sqe_head;
+ while (to_submit--) {
ktail_next++;
read_barrier();
