From: Anton Blanchard <anton@samba.org>
Date: Wed, 14 Sep 2011 09:43:15 +0000 (+0000)
Subject: powerpc: Fix deadlock in icswx code
X-Git-Tag: v3.2-rc1~34^2~70
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8bdafa39a47265bc029838b35cc6585f69224afa;p=pandora-kernel.git

powerpc: Fix deadlock in icswx code

The icswx code introduced an A-B B-A deadlock:

     CPU0                    CPU1
     ----                    ----
lock(&anon_vma->mutex);
                             lock(&mm->mmap_sem);
                             lock(&anon_vma->mutex);
lock(&mm->mmap_sem);

Instead of using the mmap_sem to keep mm_users constant, take the
page table spinlock.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

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