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authorWill Deacon <will.deacon@arm.com>2014-02-04 22:12:42 +0000
committerWill Deacon <will.deacon@arm.com>2014-02-10 17:00:49 +0000
commitc9d09e2748eaa55cac2af274574baa6368189bc1 (patch)
treeff3b8dc58a149f1949083a0a89cf497611bb0905
parent97a644208d1a08b7104d1fe2ace8cef011222711 (diff)
iommu/arm-smmu: really fix page table locking
Commit a44a9791e778 ("iommu/arm-smmu: use mutex instead of spinlock for locking page tables") replaced the page table spinlock with a mutex, to allow blocking allocations to satisfy lazy mapping requests. Unfortunately, it turns out that IOMMU mappings are created from atomic context (e.g. spinlock held during a dma_map), so this change doesn't really help us in practice. This patch is a partial revert of the offending commit, bringing back the original spinlock but replacing our page table allocations for any levels below the pgd (which is allocated during domain init) with GFP_ATOMIC instead of GFP_KERNEL. Cc: <stable@vger.kernel.org> Reported-by: Andreas Herrmann <andreas.herrmann@calxeda.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
-rw-r--r--drivers/iommu/arm-smmu.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 9f210de6537e..6eb54ae97470 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -393,7 +393,7 @@ struct arm_smmu_domain {
struct arm_smmu_cfg root_cfg;
phys_addr_t output_mask;
- struct mutex lock;
+ spinlock_t lock;
};
static DEFINE_SPINLOCK(arm_smmu_devices_lock);
@@ -901,7 +901,7 @@ static int arm_smmu_domain_init(struct iommu_domain *domain)
goto out_free_domain;
smmu_domain->root_cfg.pgd = pgd;
- mutex_init(&smmu_domain->lock);
+ spin_lock_init(&smmu_domain->lock);
domain->priv = smmu_domain;
return 0;
@@ -1138,7 +1138,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
* Sanity check the domain. We don't currently support domains
* that cross between different SMMU chains.
*/
- mutex_lock(&smmu_domain->lock);
+ spin_lock(&smmu_domain->lock);
if (!smmu_domain->leaf_smmu) {
/* Now that we have a master, we can finalise the domain */
ret = arm_smmu_init_domain_context(domain, dev);
@@ -1153,7 +1153,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
dev_name(device_smmu->dev));
goto err_unlock;
}
- mutex_unlock(&smmu_domain->lock);
+ spin_unlock(&smmu_domain->lock);
/* Looks ok, so add the device to the domain */
master = find_smmu_master(smmu_domain->leaf_smmu, dev->of_node);
@@ -1163,7 +1163,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
return arm_smmu_domain_add_master(smmu_domain, master);
err_unlock:
- mutex_unlock(&smmu_domain->lock);
+ spin_unlock(&smmu_domain->lock);
return ret;
}
@@ -1210,7 +1210,7 @@ static int arm_smmu_alloc_init_pte(struct arm_smmu_device *smmu, pmd_t *pmd,
if (pmd_none(*pmd)) {
/* Allocate a new set of tables */
- pgtable_t table = alloc_page(PGALLOC_GFP);
+ pgtable_t table = alloc_page(GFP_ATOMIC|__GFP_ZERO);
if (!table)
return -ENOMEM;
@@ -1317,7 +1317,7 @@ static int arm_smmu_alloc_init_pmd(struct arm_smmu_device *smmu, pud_t *pud,
#ifndef __PAGETABLE_PMD_FOLDED
if (pud_none(*pud)) {
- pmd = pmd_alloc_one(NULL, addr);
+ pmd = (pmd_t *)get_zeroed_page(GFP_ATOMIC);
if (!pmd)
return -ENOMEM;
@@ -1349,7 +1349,7 @@ static int arm_smmu_alloc_init_pud(struct arm_smmu_device *smmu, pgd_t *pgd,
#ifndef __PAGETABLE_PUD_FOLDED
if (pgd_none(*pgd)) {
- pud = pud_alloc_one(NULL, addr);
+ pud = (pud_t *)get_zeroed_page(GFP_ATOMIC);
if (!pud)
return -ENOMEM;
@@ -1403,7 +1403,7 @@ static int arm_smmu_handle_mapping(struct arm_smmu_domain *smmu_domain,
if (paddr & ~output_mask)
return -ERANGE;
- mutex_lock(&smmu_domain->lock);
+ spin_lock(&smmu_domain->lock);
pgd += pgd_index(iova);
end = iova + size;
do {
@@ -1419,7 +1419,7 @@ static int arm_smmu_handle_mapping(struct arm_smmu_domain *smmu_domain,
} while (pgd++, iova != end);
out_unlock:
- mutex_unlock(&smmu_domain->lock);
+ spin_unlock(&smmu_domain->lock);
/* Ensure new page tables are visible to the hardware walker */
if (smmu->features & ARM_SMMU_FEAT_COHERENT_WALK)