x86/dma: Mark iommu_pass_through as __read_mostly

This variable is read most of the time. This patch marks it
as such. It also documents the meaning the this variable
while at it.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This commit is contained in:
Joerg Roedel 2009-09-01 16:00:35 +02:00
parent 37d0892c5a
commit ac0101d396
1 changed files with 8 additions and 1 deletions

View File

@ -32,7 +32,14 @@ int no_iommu __read_mostly;
/* Set this to 1 if there is a HW IOMMU in the system */
int iommu_detected __read_mostly = 0;
int iommu_pass_through;
/*
* This variable becomes 1 if iommu=pt is passed on the kernel command line.
* If this variable is 1, IOMMU implementations do no DMA ranslation for
* devices and allow every device to access to whole physical memory. This is
* useful if a user want to use an IOMMU only for KVM device assignment to
* guests and not for driver dma translation.
*/
int iommu_pass_through __read_mostly;
dma_addr_t bad_dma_address __read_mostly = 0;
EXPORT_SYMBOL(bad_dma_address);