From: Ming Lei <ming.lei@redhat.com>
To: Liu Xiaodong <xiaodong.liu@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
Jim Harris <james.r.harris@intel.com>,
Ziyang Zhang <ZiyangZhang@linux.alibaba.com>
Subject: Re: [PATCH] block: ublk: check IO buffer based on flag need_get_data
Date: Mon, 13 Feb 2023 10:37:32 +0800 [thread overview]
Message-ID: <Y+mibLjCjiDXoPRt@T590> (raw)
In-Reply-To: <20230210141356.112321-1-xiaodong.liu@intel.com>
On Fri, Feb 10, 2023 at 09:13:56AM -0500, Liu Xiaodong wrote:
> Currently, uring_cmd with UBLK_IO_FETCH_REQ or
> UBLK_IO_COMMIT_AND_FETCH_REQ is always checked whether
> userspace server has provided IO buffer even flag
> UBLK_F_NEED_GET_DATA is configured.
>
> This is a excessive check. If UBLK_F_NEED_GET_DATA is
> configured, FETCH_RQ doesn't need to provide IO buffer;
> COMMIT_AND_FETCH_REQ also doesn't need to do that if
> the IO type is not READ.
>
> Check ub_cmd->addr together with ublk_need_get_data()
> and IO type in ublk_ch_uring_cmd().
>
> With this fix, userspace server doesn't need to preserve
> buffers for every ublk_io when flag UBLK_F_NEED_GET_DATA
> is configured, in order to save memory.
>
> Signed-off-by: Liu Xiaodong <xiaodong.liu@intel.com>
Good catch!
Fixes: c86019ff75c1 ("ublk_drv: add support for UBLK_IO_NEED_GET_DATA")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Thanks,
Ming
next prev parent reply other threads:[~2023-02-13 2:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-10 14:13 [PATCH] block: ublk: check IO buffer based on flag need_get_data Liu Xiaodong
2023-02-13 2:37 ` Ming Lei [this message]
2023-02-13 15:36 ` Jens Axboe
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