netdev - Re: [PATCH net-next v5 05/21] switchdev: convert STP update to switchdev attr set

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150506032217.GC1992@nanopsycho>
Date:	Wed, 6 May 2015 05:22:17 +0200
From:	Jiri Pirko <jiri@...nulli.us>
To:	sfeldma@...il.com
Cc:	netdev@...r.kernel.org, roopa@...ulusnetworks.com,
	linux@...ck-us.net, f.fainelli@...il.com,
	sridhar.samudrala@...el.com, ronen.arad@...el.com, andrew@...n.ch,
	simon.horman@...ronome.com
Subject: Re: [PATCH net-next v5 05/21] switchdev: convert STP update to
 switchdev attr set

Tue, May 05, 2015 at 07:34:41PM CEST, sfeldma@...il.com wrote:
>From: Scott Feldman <sfeldma@...il.com>
>
>STP update is just a settable port attribute, so convert
>switchdev_port_stp_update to an attr set.
>
>For rocker, support prepare-commit transaction model for setting STP state.
>This requires rocker to preallocate memory needed for the commit up front
>in the prepare phase.  Since rtnl_lock is held between prepare-commit,
>store the allocated memory on a queue hanging off of the rocker_port.
>Also, in prepare phase, do everything right up to calling into HW.  The
>same code paths are tranversed in the driver for both prepare and commit
>phases.  In some cases, any state modified in the prepare phase must be
>reverted before returning so the commit phase makes the same decisions.
>
>For rocker, as a consequence of holding rtnl_lock in process context for
>all attr sets (and obj adds), all memory is GFP_KERNEL allocated and we
>don't need to busy spin waiting for the device to complete the command.  So
>the bulk of this patch is simplifying the memory allocations to only use
>GFP_KERNEL and to remove the nowait flag and busy spin loop.
>
>For DSA, the prepare phase is skipped and STP updates are only done in the
>commit phase.  This is because currently the DSA drivers don't need to
>allocate any memory for STP updates and the STP update will not fail to HW
>(unless something horrible goes wrong on the MDIO bus, in which case the
>prepare phase wouldn't have been able to predict anyway).
>
>Signed-off-by: Scott Feldman <sfeldma@...il.com>

Hmm. This patch looks like a squash of two independent patches. It would
be better to push alloc change and stp update change as separate
patches.

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html