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iommu/amd: Fix alloc_irq_index() increment

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On an is_allocated() interrupt index, we ALIGN() the current index and
then increment it via the for loop, guaranteeing that it is no longer
aligned for alignments >1.  We instead need to align the next index,
to guarantee forward progress, moving the increment-only to the case
where the index was found to be unallocated.

Fixes: 37946d95fc ('iommu/amd: Add align parameter to alloc_irq_index()')
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Alex Williamson 2017-11-03 10:50:31 -06:00
parent a593472591
commit 07d1c91b6c
1 changed files with 4 additions and 3 deletions
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7
drivers/iommu/amd_iommu.c
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@ -3682,13 +3682,12 @@ static int alloc_irq_index(u16 devid, int count, bool align)
/* Scan table for free entries */
for (index = ALIGN(table->min_index, alignment), c = 0;
index < MAX_IRQS_PER_TABLE;
index++) {
index < MAX_IRQS_PER_TABLE;) {
if (!iommu->irte_ops->is_allocated(table, index)) {
c += 1;
} else {
c = 0;
index = ALIGN(index, alignment);
index = ALIGN(index + 1, alignment);
continue;
}
@ -3699,6 +3698,8 @@ static int alloc_irq_index(u16 devid, int count, bool align)
index -= count - 1;
goto out;
}
index++;
}
index = -ENOSPC;