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From: Jeff Moyer <jmoyer@redhat.com>
To: Jackie Liu <liuyun01@kylinos.cn>
Cc: axboe@kernel.dk, linux-block@vger.kernel.org
Subject: Re: [PATCH] io_uring: ensure cq_entries is at least equal to or greater than sq_entries
Date: Wed, 23 Oct 2019 14:42:01 -0400	[thread overview]
Message-ID: <x49d0ennw1y.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <1571795864-56669-1-git-send-email-liuyun01@kylinos.cn> (Jackie Liu's message of "Wed, 23 Oct 2019 09:57:44 +0800")

Jackie Liu <liuyun01@kylinos.cn> writes:

> If cq_entries is smaller than sq_entries, it will cause a lot of overflow
> to appear. when customizing cq_entries, at least let him be no smaller than
> sq_entries.
>
> Fixes: 95d8765bd9f2 ("io_uring: allow application controlled CQ ring size")
> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
> ---
>  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 b64cd2c..dfa9731 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -3784,7 +3784,7 @@ 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.
>  		 */
> -		if (!p->cq_entries || p->cq_entries > IORING_MAX_CQ_ENTRIES)
> +		if (p->cq_entries < p->sq_entries || p->cq_entries > IORING_MAX_CQ_ENTRIES)

What if they're both zero?  I think you want to keep that check.

-Jeff


  reply	other threads:[~2019-10-23 18:42 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-23  1:57 [PATCH] io_uring: ensure cq_entries is at least equal to or greater than sq_entries Jackie Liu
2019-10-23 18:42 ` Jeff Moyer [this message]
2019-10-23 19:41   ` Jens Axboe
2019-10-24  0:22     ` Jackie Liu
2019-10-24  3:26       ` Jens Axboe

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