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Subject[PATCH v7 08/15] iommu: Add support for the map_pages() callback
Date
From: "Isaac J. Manjarres" <isaacm@codeaurora.org>

Since iommu_pgsize can calculate how many pages of the
same size can be mapped/unmapped before the next largest
page size boundary, add support for invoking an IOMMU
driver's map_pages() callback, if it provides one.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com>
---
drivers/iommu/iommu.c | 43 +++++++++++++++++++++++++++++++++++--------
1 file changed, 35 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 725622c7e603..70a729ce88b1 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2429,6 +2429,30 @@ static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
return pgsize;
}

+static int __iommu_map_pages(struct iommu_domain *domain, unsigned long iova,
+ phys_addr_t paddr, size_t size, int prot,
+ gfp_t gfp, size_t *mapped)
+{
+ const struct iommu_ops *ops = domain->ops;
+ size_t pgsize, count;
+ int ret;
+
+ pgsize = iommu_pgsize(domain, iova, paddr, size, &count);
+
+ pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx count %zu\n",
+ iova, &paddr, pgsize, count);
+
+ if (ops->map_pages) {
+ ret = ops->map_pages(domain, iova, paddr, pgsize, count, prot,
+ gfp, mapped);
+ } else {
+ ret = ops->map(domain, iova, paddr, pgsize, prot, gfp);
+ *mapped = ret ? 0 : pgsize;
+ }
+
+ return ret;
+}
+
static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
{
@@ -2439,7 +2463,7 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t orig_paddr = paddr;
int ret = 0;

- if (unlikely(ops->map == NULL ||
+ if (unlikely(!(ops->map || ops->map_pages) ||
domain->pgsize_bitmap == 0UL))
return -ENODEV;

@@ -2463,18 +2487,21 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
pr_debug("map: iova 0x%lx pa %pa size 0x%zx\n", iova, &paddr, size);

while (size) {
- size_t pgsize = iommu_pgsize(domain, iova, paddr, size, NULL);
+ size_t mapped = 0;

- pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
- iova, &paddr, pgsize);
- ret = ops->map(domain, iova, paddr, pgsize, prot, gfp);
+ ret = __iommu_map_pages(domain, iova, paddr, size, prot, gfp,
+ &mapped);
+ /*
+ * Some pages may have been mapped, even if an error occurred,
+ * so we should account for those so they can be unmapped.
+ */
+ size -= mapped;

if (ret)
break;

- iova += pgsize;
- paddr += pgsize;
- size -= pgsize;
+ iova += mapped;
+ paddr += mapped;
}

/* unroll mapping in case something went wrong */
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