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* [PATCH] io_uring: compare cached_cq_tail with cq.head in_io_uring_poll
@ 2019-09-24 12:53 yangerkun
  2019-09-24 13:22 ` Jens Axboe
  0 siblings, 1 reply; 2+ messages in thread
From: yangerkun @ 2019-09-24 12:53 UTC (permalink / raw)
  To: hristo, axboe; +Cc: linux-block, yi.zhang, houtao1, yangerkun

After 75b28af("io_uring: allocate the two rings together"), we compare
sq.head with cached_cq_tail to determine does there any cq invalid.
Actually, we should use cq.head.

Fixes: 75b28af ("io_uring: allocate the two rings together")
Signed-off-by: yangerkun <yangerkun@huawei.com>
---
 fs/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 0dadbdbead0f..63cbefba1fb5 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3263,7 +3263,7 @@ static __poll_t io_uring_poll(struct file *file, poll_table *wait)
 	if (READ_ONCE(ctx->rings->sq.tail) - ctx->cached_sq_head !=
 	    ctx->rings->sq_ring_entries)
 		mask |= EPOLLOUT | EPOLLWRNORM;
-	if (READ_ONCE(ctx->rings->sq.head) != ctx->cached_cq_tail)
+	if (READ_ONCE(ctx->rings->cq.head) != ctx->cached_cq_tail)
 		mask |= EPOLLIN | EPOLLRDNORM;
 
 	return mask;
-- 
2.17.2


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] io_uring: compare cached_cq_tail with cq.head in_io_uring_poll
  2019-09-24 12:53 [PATCH] io_uring: compare cached_cq_tail with cq.head in_io_uring_poll yangerkun
@ 2019-09-24 13:22 ` Jens Axboe
  0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2019-09-24 13:22 UTC (permalink / raw)
  To: yangerkun, hristo; +Cc: linux-block, yi.zhang, houtao1

On 9/24/19 6:53 AM, yangerkun wrote:
> After 75b28af("io_uring: allocate the two rings together"), we compare
> sq.head with cached_cq_tail to determine does there any cq invalid.
> Actually, we should use cq.head.

Nice catch, applied. BTW, note for future submissions, this:

> Fixes: 75b28af ("io_uring: allocate the two rings together")

sha should be 12 characters. I will fix it up in this one.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 2+ messages in thread

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2019-09-24 12:53 [PATCH] io_uring: compare cached_cq_tail with cq.head in_io_uring_poll yangerkun
2019-09-24 13:22 ` Jens Axboe

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