From: Peter Hurley <peter@hurleysoftware.com>
Date: Thu, 16 Oct 2014 19:33:26 +0000 (-0400)
Subject: pty: Don't claim slave's ctrl_lock for master's packet mode
X-Git-Tag: omap-for-v3.19/fixes-rc1~86^2~200
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=54e8e5fcaae109f0303f52efb24f29bfac79ca86;p=pandora-kernel.git

pty: Don't claim slave's ctrl_lock for master's packet mode

The slave's ctrl_lock serializes updates to the ctrl_status field
only, whereas the master's ctrl_lock serializes updates to the
packet mode enable (ie., the master does not have ctrl_status and
the slave does not have packet mode). Thus, claiming the slave's
ctrl_lock to access ->packet is useless.

Unlocked reads of ->packet are already smp-safe.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

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