From: Paolo Bonzini <pbonzini@redhat.com>
To: Markus Elfring <Markus.Elfring@web.de>,
Xianting Tian <xianting_tian@126.com>,
linux-scsi@vger.kernel.org,
virtualization@lists.linux-foundation.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org,
"James E. J. Bottomley" <jejb@linux.ibm.com>,
Jason Wang <jasowang@redhat.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [PATCH] scsi: virtio_scsi: Remove unnecessary condition checks
Date: Fri, 10 Jul 2020 07:17:59 +0000 [thread overview]
Message-ID: <58e3feb8-1ffb-f77f-cf3a-75222b3cd524@redhat.com> (raw)
In-Reply-To: <8eb9a827-45f1-e71c-0cbf-1c29acd8e310@web.de>
On 10/07/20 08:32, Markus Elfring wrote:
>>>> + mempool_destroy(virtscsi_cmd_pool);
>>>> + virtscsi_cmd_pool = NULL;
>>>> + kmem_cache_destroy(virtscsi_cmd_cache);
>>>> + virtscsi_cmd_cache = NULL;
>>>> return ret;
>>>> }
>>>
>>> How do you think about to add a jump target so that the execution
>>> of a few statements can be avoided according to a previous
>>> null pointer check?
>>
>> The point of the patch is precisely to simplify the code,
>
> I suggest to reconsider also Linux coding style aspects
> for the implementation of the function “init”.
> https://elixir.bootlin.com/linux/v5.8-rc4/source/drivers/scsi/virtio_scsi.c#L980
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/scsi/virtio_scsi.c?idBf82040ee66db13525dc6f14b8559890b2f4c1c#n980
>
> if (!virtscsi_cmd_cache) {
> pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
> - goto error;
> + return -ENOMEM;
> }
Could be doable, but I don't see a particular benefit. Having a single
error loop is an advantage by itself.
The coding style is a suggestion. Note the difference between
kfree(foo->bar);
kfree(foo);
and
kfree(bar);
kfree(foo);
> See also:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?idBf82040ee66db13525dc6f14b8559890b2f4c1c#n461
>
>
>> executing a couple more instruction is not an issue.
>
> With which update steps would like to achieve such a code variant?
>
> destroy_pool:
> mempool_destroy(virtscsi_cmd_pool);
> virtscsi_cmd_pool = NULL;
> destroy_cache:
> kmem_cache_destroy(virtscsi_cmd_cache);
> virtscsi_cmd_cache = NULL;
> return ret;
... while there's no advantage in this.
Paolo
next prev parent reply other threads:[~2020-07-10 7:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 17:16 [PATCH] scsi: virtio_scsi: Remove unnecessary condition checks Markus Elfring
2020-07-09 17:25 ` Paolo Bonzini
2020-07-09 20:55 ` Markus Elfring
2020-07-10 6:32 ` Markus Elfring
2020-07-10 7:17 ` Paolo Bonzini [this message]
2020-07-10 7:40 ` Markus Elfring
2020-07-10 7:46 ` Paolo Bonzini
2020-07-10 8:11 ` Markus Elfring
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