diff options
authorJens Axboe <>2020-11-11 10:38:53 -0700
committerJens Axboe <>2020-11-11 10:42:41 -0700
commit88ec3211e46344a7d10cf6cb5045f839f7785f8e (patch)
parent9a472ef7a3690ac0b77ebfb04c88fa795de2adea (diff)
io_uring: round-up cq size before comparing with rounded sq sizeio_uring-5.10-2020-11-13
If an application specifies IORING_SETUP_CQSIZE to set the CQ ring size to a specific size, we ensure that the CQ size is at least that of the SQ ring size. But in doing so, we compare the already rounded up to power of two SQ size to the as-of yet unrounded CQ size. This means that if an application passes in non power of two sizes, we can return -EINVAL when the final value would've been fine. As an example, an application passing in 100/100 for sq/cq size should end up with 128 for both. But since we round the SQ size first, we compare the CQ size of 100 to 128, and return -EINVAL as that is too small. Cc: Fixes: 33a107f0a1b8 ("io_uring: allow application controlled CQ ring size") Reported-by: Dan Melnic <> Signed-off-by: Jens Axboe <>
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8018c7076b25..c77584de68d7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -9226,6 +9226,7 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
* to a power-of-two, if it isn't already. We do NOT impose
* any cq vs sq ring sizing.
+ p->cq_entries = roundup_pow_of_two(p->cq_entries);
if (p->cq_entries < p->sq_entries)
return -EINVAL;
if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
@@ -9233,7 +9234,6 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
return -EINVAL;
p->cq_entries = IORING_MAX_CQ_ENTRIES;
- p->cq_entries = roundup_pow_of_two(p->cq_entries);
} else {
p->cq_entries = 2 * p->sq_entries;