From: Jeff Dike <jdike@addtoit.com>
To: SF Markus Elfring <elfring@users.sourceforge.net>
Cc: user-mode-linux-devel@lists.sourceforge.net,
user-mode-linux-user@lists.sourceforge.net,
Anton Ivanov <aivanov@kot-begemot.co.uk>,
Dan Williams <dan.j.williams@intel.com>,
Hannes Reinecke <hare@suse.com>, Jens Axboe <axboe@fb.com>,
Richard Weinberger <richard@nod.at>,
LKML <linux-kernel@vger.kernel.org>,
kernel-janitors@vger.kernel.org
Subject: Re: [PATCH 1/5] um: port: Move an assignment for the variable "fd" in port_wait()
Date: Wed, 18 Jan 2017 19:03:30 -0500 [thread overview]
Message-ID: <20170119000330.GA12052@parts.user-mode-linux.org> (raw)
In-Reply-To: <4940ae24-c7ae-66ce-4c2a-5283607a5549@users.sourceforge.net>
On Wed, Jan 18, 2017 at 10:56:17PM +0100, SF Markus Elfring wrote:
> diff --git a/arch/um/drivers/port_kern.c b/arch/um/drivers/port_kern.c
> index 40ca5cc275e9..b2bbda21c5f3 100644
> --- a/arch/um/drivers/port_kern.c
> +++ b/arch/um/drivers/port_kern.c
> @@ -230,10 +230,10 @@ int port_wait(void *data)
>
> atomic_inc(&port->wait_count);
> while (1) {
> - fd = -ERESTARTSYS;
> - if (wait_for_completion_interruptible(&port->done))
> + if (wait_for_completion_interruptible(&port->done)) {
> + fd = -ERESTARTSYS;
> goto out;
> -
> + }
> spin_lock(&port->lock);
>
> conn = list_entry(port->connections.next, struct connection,
> --
> 2.11.0
>
The current code is pretty standard kernel coding style. The inline
fd = -ERESTARTSYS;
is likely free, or close to it, and I believe that having anything
besides a goto inside the if could make it significantly more
expensive.
Jeff
--
Jeff Dike
AddToIt
978-254-0789 (o)
978-394-8986 (c)
next prev parent reply other threads:[~2017-01-19 0:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-18 21:55 [PATCH 0/5] UM: Fine-tuning for some function implementations SF Markus Elfring
2017-01-18 21:56 ` [PATCH 1/5] um: port: Move an assignment for the variable "fd" in port_wait() SF Markus Elfring
2017-01-19 0:03 ` Jeff Dike [this message]
2017-01-18 21:57 ` [PATCH 2/5] um: port: Delete three error messages for a failed memory allocation SF Markus Elfring
2017-01-19 0:07 ` Jeff Dike
2017-01-19 9:38 ` SF Markus Elfring
2017-01-18 21:58 ` [PATCH 3/5] um: port: Improve size determinations in port_data() SF Markus Elfring
2017-01-18 21:59 ` [PATCH 4/5] um: ubd: Move two assignments for the variable "err" in ubd_remove() SF Markus Elfring
2017-01-18 22:00 ` [PATCH 5/5] um: ubd: Improve size determinations in do_ubd_request() SF Markus Elfring
2017-01-19 7:56 ` [PATCH 0/5] UM: Fine-tuning for some function implementations Richard Weinberger
2017-01-19 17:13 ` SF Markus Elfring
2017-01-19 18:44 ` Anton Ivanov
2017-01-20 5:11 ` [PATCH 0/5] " Jeff Dike
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