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powerpc/kernel: Avoid preemption check in iommu_range_alloc() 

Replace the __this_cpu_read() with raw_cpu_read() in
iommu_range_alloc(). Otherwise we get a warning about using
__this_cpu_read() in preemptible code:

  BUG: using __this_cpu_read() in preemptible
  caller is iommu_range_alloc+0xa8/0x3d0

Preemption doesn't need to be disabled since according to the comment
any CPU can safely use any IOMMU pool.

Signed-off-by: Victor Aoqui <victora@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Victor Aoqui 2017-07-20 14:26:06 -03:00 committed by Michael Ellerman
parent 24be85a23d
commit 75f327c6b7
1 changed files with 1 additions and 1 deletions
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2
arch/powerpc/kernel/iommu.c
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@ -208,7 +208,7 @@ static unsigned long iommu_range_alloc(struct device *dev,
* We don't need to disable preemption here because any CPU can
* safely use any IOMMU pool.
*/
pool_nr = __this_cpu_read(iommu_pool_hash) & (tbl->nr_pools - 1);
pool_nr = raw_cpu_read(iommu_pool_hash) & (tbl->nr_pools - 1);
if (largealloc)
pool = &(tbl->large_pool);