From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Mon, 10 Sep 2012 14:14:16 +0000 (+0200)
Subject: arm: mm: fix DMA pool affiliation check
X-Git-Tag: v3.6-rc6~12^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f3d87524975f01b885fc3d009c6ab6afd0d00746;p=pandora-kernel.git

arm: mm: fix DMA pool affiliation check

The __free_from_pool() function was changed in
e9da6e9905e639b0f842a244bc770b48ad0523e9. Unfortunately, the test that
checks whether the provided (start,size) is within the DMA pool has
been improperly modified. It used to be:

  if (start < coherent_head.vm_start || end > coherent_head.vm_end)

Where coherent_head.vm_end was non-inclusive (i.e, it did not include
the first byte after the pool). The test has been changed to:

  if (start < pool->vaddr || start > pool->vaddr + pool->size)

So now pool->vaddr + pool->size is inclusive (i.e, it includes the
first byte after the pool), so the test should be >= instead of >.

This bug causes the following message when freeing the *first* DMA
coherent buffer that has been allocated, because its virtual address
is exactly equal to pool->vaddr + pool->size :

WARNING: at /home/thomas/projets/linux-2.6/arch/arm/mm/dma-mapping.c:463 __free_from_pool+0xa4/0xc0()
freeing wrong coherent size from pool

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Lior Amsalem <alior@marvell.com>
Cc: Maen Suleiman <maen@marvell.com>
Cc: Tawfik Bayouk <tawfik@marvell.com>
Cc: Shadi Ammouri <shadi@marvell.com>
Cc: Eran Ben-Avi <benavi@marvell.com>
Cc: Yehuda Yitschak <yehuday@marvell.com>
Cc: Nadav Haklai <nadavh@marvell.com>
[m.szyprowski: rebased onto v3.6-rc5 and resolved conflict]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---

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