From: Roland Dreier <roland@purestorage.com>
Date: Wed, 26 Sep 2012 04:24:07 +0000 (-0700)
Subject: mlx4_core: Fix crash on uninitialized priv->cmd.slave_sem
X-Git-Tag: omap-for-v3.7-rc1/fixes-cpufreq-signed~42^2^5~3
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f3d4c89ee4a8c993cc334a67f84a3fb724a1dd35;p=pandora-kernel.git

mlx4_core: Fix crash on uninitialized priv->cmd.slave_sem

On an SR-IOV master device, __mlx4_init_one() calls mlx4_init_hca()
before mlx4_multi_func_init().  However, for unlucky configurations,
mlx4_init_hca() might call mlx4_SENSE_PORT() (via mlx4_dev_cap()), and
that calls mlx4_cmd_imm() with MLX4_CMD_WRAPPED set.

However, on a multifunction device with MLX4_CMD_WRAPPED, __mlx4_cmd()
calls into mlx4_slave_cmd(), and that immediately tries to do

	down(&priv->cmd.slave_sem);

but priv->cmd.slave_sem isn't initialized until mlx4_multi_func_init()
(which we haven't called yet).  The next thing it tries to do is access
priv->mfunc.vhcr, but that hasn't been allocated yet.

Fix this by moving the initialization of slave_sem and vhcr up into
mlx4_cmd_init(). Also, since slave_sem is really just being used as a
mutex, convert it into a slave_cmd_mutex.

Signed-off-by: Roland Dreier <roland@purestorage.com>
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