[PATCH v1 06/11] io_uring: modify io_get_cqe for CQE32

Stefan Roesch
2022-04-19T20:56:51Z

Modify accesses to the CQE array to take large CQE's into account. The
index needs to be shifted by one for large CQE's.

Signed-off-by: Stefan Roesch <shr@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index c93a9353c88d..bd352815b9e7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1909,8 +1909,12 @@ static noinline struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);
+ unsigned int shift = 0;
unsigned int free, queued, len;

+ if (ctx->flags & IORING_SETUP_CQE32)
+ shift = 1;
+
/* userspace may cheat modifying the tail, be safe and do min */
queued = min(__io_cqring_events(ctx), ctx->cq_entries);
free = ctx->cq_entries - queued;
@@ -1922,12 +1926,13 @@ static noinline struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx)
ctx->cached_cq_tail++;
ctx->cqe_cached = &rings->cqes[off];
ctx->cqe_sentinel = ctx->cqe_cached + len;
- return ctx->cqe_cached++;
+ ctx->cqe_cached++;
+ return &rings->cqes[off << shift];
}

static inline struct io_uring_cqe *io_get_cqe(struct io_ring_ctx *ctx)
{
- if (likely(ctx->cqe_cached < ctx->cqe_sentinel)) {
+ if (likely(ctx->cqe_cached < ctx->cqe_sentinel && !(ctx->flags & IORING_SETUP_CQE32))) {
ctx->cached_cq_tail++;
return ctx->cqe_cached++;
}
--
2.30.2