From: Keith Busch <keith.busch@intel.com>
To: kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] scsi: Fix a harmless double shift bug
Date: Thu, 29 Nov 2018 15:08:56 +0000 [thread overview]
Message-ID: <20181129150856.GB8332@localhost.localdomain> (raw)
In-Reply-To: <20181129103709.nthxjmmmlb2pdr6g@kili.mountain>
On Thu, Nov 29, 2018 at 01:37:10PM +0300, Dan Carpenter wrote:
> Smatch generates a warning:
>
> drivers/scsi/scsi_lib.c:1656 scsi_mq_done() warn: test_bit() takes a bit number
>
> The problem is that SCMD_STATE_COMPLETE is supposed to be bit number 0
> and not a mask like "(1 << 0)". It is used like this:
>
> if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
>
> The test_and_set_bit() has a shift built in so it's a double left shift
> and uses bit number 1 instead of number 0. This bug is harmless because
> it's done consistently and it doesn't clash with any other flags.
>
> Fixes: f1342709d18a ("scsi: Do not rely on blk-mq for double completions")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Nice catch, thanks for the fix.
Reviewed-by: Keith Busch <keith.busch@intel.com>
next prev parent reply other threads:[~2018-11-29 15:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-29 10:37 [PATCH] scsi: Fix a harmless double shift bug Dan Carpenter
2018-11-29 15:08 ` Keith Busch [this message]
2018-12-08 3:20 ` Martin K. Petersen
2018-12-08 4:25 ` Jens Axboe
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