Annotation of /trunk/kernel26-magellan/patches-2.6.16-r12/0105-2.6.16.12-race-free_iommu_patch.patch
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Mon Jun 5 09:25:38 2006 UTC (18 years, 3 months ago) by niro
File size: 1397 byte(s)
Mon Jun 5 09:25:38 2006 UTC (18 years, 3 months ago) by niro
File size: 1397 byte(s)
ver bump to 2.6.16-r12: - updated to linux-2.6.16.19 - updated to ck11
1 | niro | 72 | From: Mike Waychison <mikew@google.com> |
2 | Date: Fri, 21 Apr 2006 07:43:25 +0000 (+0200) | ||
3 | Subject: [PATCH] x86_64: Fix a race in the free_iommu path. | ||
4 | X-Git-Url: http://www.kernel.org/git/?p=linux/kernel/git/stable/linux-2.6.16.y.git;a=commitdiff;h=c89ce82c2d942daacc7d7f5d3efafe7dba70bd23 | ||
5 | |||
6 | [PATCH] x86_64: Fix a race in the free_iommu path. | ||
7 | |||
8 | We do this by removing a micro-optimization that tries to avoid grabbing | ||
9 | the iommu_bitmap_lock spinlock and using a bus-locked operation. | ||
10 | |||
11 | This still races with other simultaneous alloc_iommu or free_iommu(size | ||
12 | > 1) which both use bus-unlocked operations. | ||
13 | |||
14 | The end result of this race is eventually ending | ||
15 | up with an iommu_gart_bitmap that has bits errornously set all over, | ||
16 | making large contiguous iommu space allocations fail with 'PCI-DMA: | ||
17 | Out of IOMMU space'. | ||
18 | |||
19 | Signed-off-by: Mike Waychison <mikew@google.com> | ||
20 | Signed-off-by: Andi Kleen <ak@suse.de> | ||
21 | Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> | ||
22 | --- | ||
23 | |||
24 | --- a/arch/x86_64/kernel/pci-gart.c | ||
25 | +++ b/arch/x86_64/kernel/pci-gart.c | ||
26 | @@ -114,10 +114,6 @@ static unsigned long alloc_iommu(int siz | ||
27 | static void free_iommu(unsigned long offset, int size) | ||
28 | { | ||
29 | unsigned long flags; | ||
30 | - if (size == 1) { | ||
31 | - clear_bit(offset, iommu_gart_bitmap); | ||
32 | - return; | ||
33 | - } | ||
34 | spin_lock_irqsave(&iommu_bitmap_lock, flags); | ||
35 | __clear_bit_string(iommu_gart_bitmap, offset, size); | ||
36 | spin_unlock_irqrestore(&iommu_bitmap_lock, flags); |