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From: Ming Lei <[email protected]>
To: Jens Axboe <[email protected]>
Cc: io-uring <[email protected]>,
	"[email protected]" <[email protected]>
Subject: Re: [PATCH] ublk: read any SQE values upfront
Date: Thu, 6 Apr 2023 10:53:35 +0800	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On Wed, Apr 05, 2023 at 08:03:57PM -0600, Jens Axboe wrote:
> Since SQE memory is shared with userspace, we should only be reading it
> once. We cannot read it multiple times, particularly when it's read once
> for validation and then read again for the actual use.
> 
> ublk_ch_uring_cmd() is safe when called as a retry operation, as the
> memory backing is stable at that point. But for normal issue, we want
> to ensure that we only read ublksrv_io_cmd once. Wrap the function in
> a helper that reads the value into an on-stack copy of the struct.
> 
> Cc: [email protected] # 6.0+
> Signed-off-by: Jens Axboe <[email protected]>

Reviewed-by: Ming Lei <[email protected]>


Thanks,
Ming


      reply	other threads:[~2023-04-06  2:55 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-06  2:03 [PATCH] ublk: read any SQE values upfront Jens Axboe
2023-04-06  2:53 ` Ming Lei [this message]

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