From: Will Deacon <will.deacon@arm.com>
Date: Thu, 7 Nov 2013 18:47:50 +0000 (+0000)
Subject: iommu/arm-smmu: use mutex instead of spinlock for locking page tables
X-Git-Tag: v3.13-rc4~30^2^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a44a9791e778d9ccda50d5534028ed4057a9a45b;p=pandora-kernel.git

iommu/arm-smmu: use mutex instead of spinlock for locking page tables

When creating IO mappings, we lazily allocate our page tables using the
standard, non-atomic allocator functions. This presents us with a
problem, since our page tables are protected with a spinlock.

This patch reworks the smmu_domain lock to use a mutex instead of a
spinlock. iova_to_phys is then reworked so that it only reads the page
tables, and can run in a lockless fashion, leaving the mutex to guard
against concurrent mapping threads.

Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---

Reading git-diff-tree failed