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Subject[PATCH 1/9] iommu/dma-iommu: Add iommu_map_atomic
Date
The iommu ops .map function (or the iommu_map function which calls it)
was always supposed to be sleepable (according to Joerg's comment in
this thread: https://lore.kernel.org/patchwork/patch/977520/ ) and so
should probably have had a "might_sleep()" since it was written. However
currently the dma-iommu api can call iommu_map in an atomic context,
which it shouldn't do. This doesn't cause any problems because any iommu
driver which uses the dma-iommu api uses gfp_atomic in it's iommu_ops
.map function. But doing this wastes the memory allocators atomic pools.

Add a new function iommu_map_atomic, use it in the dma-iommu api and add
“might_sleep()” to the iommu_map function.

After this change all drivers which use the dma-iommu api need to
implement the new iommu ops .map_atomic function. For the moment just
reuse the driver's iommus ops .map function for .map_atomic.

Signed-off-by: Tom Murphy <tmurphy@arista.com>
---
drivers/iommu/arm-smmu-v3.c | 1 +
drivers/iommu/arm-smmu.c | 1 +
drivers/iommu/dma-iommu.c | 6 ++---
drivers/iommu/exynos-iommu.c | 1 +
drivers/iommu/iommu.c | 46 +++++++++++++++++++++++++++++-----
drivers/iommu/ipmmu-vmsa.c | 1 +
drivers/iommu/mtk_iommu.c | 1 +
drivers/iommu/qcom_iommu.c | 1 +
drivers/iommu/rockchip-iommu.c | 1 +
include/linux/iommu.h | 22 ++++++++++++++++
10 files changed, 72 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index d3880010c6cf..c64ba333c05a 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2055,6 +2055,7 @@ static struct iommu_ops arm_smmu_ops = {
.domain_free = arm_smmu_domain_free,
.attach_dev = arm_smmu_attach_dev,
.map = arm_smmu_map,
+ .map_atomic = arm_smmu_map,
.unmap = arm_smmu_unmap,
.flush_iotlb_all = arm_smmu_flush_iotlb_all,
.iotlb_sync = arm_smmu_iotlb_sync,
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 045d93884164..836ec6d0bba5 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1691,6 +1691,7 @@ static struct iommu_ops arm_smmu_ops = {
.domain_free = arm_smmu_domain_free,
.attach_dev = arm_smmu_attach_dev,
.map = arm_smmu_map,
+ .map_atomic = arm_smmu_map,
.unmap = arm_smmu_unmap,
.flush_iotlb_all = arm_smmu_flush_iotlb_all,
.iotlb_sync = arm_smmu_iotlb_sync,
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 77aabe637a60..1a4bff3f8427 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -590,7 +590,7 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
sg_miter_stop(&miter);
}

- if (iommu_map_sg(domain, iova, sgt.sgl, sgt.orig_nents, prot)
+ if (iommu_map_sg_atomic(domain, iova, sgt.sgl, sgt.orig_nents, prot)
< size)
goto out_free_sg;

@@ -648,7 +648,7 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
if (!iova)
return DMA_MAPPING_ERROR;

- if (iommu_map(domain, iova, phys - iova_off, size, prot)) {
+ if (iommu_map_atomic(domain, iova, phys - iova_off, size, prot)) {
iommu_dma_free_iova(cookie, iova, size);
return DMA_MAPPING_ERROR;
}
@@ -809,7 +809,7 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
* We'll leave any physical concatenation to the IOMMU driver's
* implementation - it knows better than we do.
*/
- if (iommu_map_sg(domain, iova, sg, nents, prot) < iova_len)
+ if (iommu_map_sg_atomic(domain, iova, sg, nents, prot) < iova_len)
goto out_free_iova;

return __finalise_sg(dev, sg, nents, iova);
diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 05c6bc099d62..bf1281aa12bc 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -1332,6 +1332,7 @@ static const struct iommu_ops exynos_iommu_ops = {
.attach_dev = exynos_iommu_attach_device,
.detach_dev = exynos_iommu_detach_device,
.map = exynos_iommu_map,
+ .map_atomic = exynos_iommu_map,
.unmap = exynos_iommu_unmap,
.iova_to_phys = exynos_iommu_iova_to_phys,
.device_group = generic_device_group,
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 33a982e33716..1eaf0aed0aff 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1582,8 +1582,8 @@ static size_t iommu_pgsize(struct iommu_domain *domain,
return pgsize;
}

-int iommu_map(struct iommu_domain *domain, unsigned long iova,
- phys_addr_t paddr, size_t size, int prot)
+int __iommu_map(struct iommu_domain *domain, unsigned long iova,
+ phys_addr_t paddr, size_t size, int prot, bool is_atomic)
{
const struct iommu_ops *ops = domain->ops;
unsigned long orig_iova = iova;
@@ -1620,8 +1620,12 @@ int iommu_map(struct iommu_domain *domain, unsigned long iova,

pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
iova, &paddr, pgsize);
+ if (is_atomic)
+ ret = ops->map_atomic(domain, iova, paddr, pgsize,
+ prot);
+ else
+ ret = ops->map(domain, iova, paddr, pgsize, prot);

- ret = ops->map(domain, iova, paddr, pgsize, prot);
if (ret)
break;

@@ -1641,8 +1645,22 @@ int iommu_map(struct iommu_domain *domain, unsigned long iova,

return ret;
}
+
+int iommu_map(struct iommu_domain *domain, unsigned long iova,
+ phys_addr_t paddr, size_t size, int prot)
+{
+ might_sleep();
+ return __iommu_map(domain, iova, paddr, size, prot, false);
+}
EXPORT_SYMBOL_GPL(iommu_map);

+int iommu_map_atomic(struct iommu_domain *domain, unsigned long iova,
+ phys_addr_t paddr, size_t size, int prot)
+{
+ return __iommu_map(domain, iova, paddr, size, prot, true);
+}
+EXPORT_SYMBOL_GPL(iommu_map_atomic);
+
static size_t __iommu_unmap(struct iommu_domain *domain,
unsigned long iova, size_t size,
bool sync)
@@ -1717,8 +1735,9 @@ size_t iommu_unmap_fast(struct iommu_domain *domain,
}
EXPORT_SYMBOL_GPL(iommu_unmap_fast);

-size_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
- struct scatterlist *sg, unsigned int nents, int prot)
+size_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
+ struct scatterlist *sg, unsigned int nents, int prot,
+ bool is_atomic)
{
size_t len = 0, mapped = 0;
phys_addr_t start;
@@ -1729,7 +1748,9 @@ size_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
phys_addr_t s_phys = sg_phys(sg);

if (len && s_phys != start + len) {
- ret = iommu_map(domain, iova + mapped, start, len, prot);
+ ret = __iommu_map(domain, iova + mapped, start,
+ len, prot, is_atomic);
+
if (ret)
goto out_err;

@@ -1757,8 +1778,21 @@ size_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
return 0;

}
+
+size_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
+ struct scatterlist *sg, unsigned int nents, int prot)
+{
+ return __iommu_map_sg(domain, iova, sg, nents, prot, false);
+}
EXPORT_SYMBOL_GPL(iommu_map_sg);

+size_t iommu_map_sg_atomic(struct iommu_domain *domain, unsigned long iova,
+ struct scatterlist *sg, unsigned int nents, int prot)
+{
+ return __iommu_map_sg(domain, iova, sg, nents, prot, true);
+}
+EXPORT_SYMBOL_GPL(iommu_map_sg_atomic);
+
int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr,
phys_addr_t paddr, u64 size, int prot)
{
diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 9a380c10655e..c2e0cdb9e784 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -931,6 +931,7 @@ static const struct iommu_ops ipmmu_ops = {
.attach_dev = ipmmu_attach_device,
.detach_dev = ipmmu_detach_device,
.map = ipmmu_map,
+ .map_atomic = ipmmu_map,
.unmap = ipmmu_unmap,
.flush_iotlb_all = ipmmu_iotlb_sync,
.iotlb_sync = ipmmu_iotlb_sync,
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index de3e02277b70..ed8f768f46b6 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -497,6 +497,7 @@ static const struct iommu_ops mtk_iommu_ops = {
.attach_dev = mtk_iommu_attach_device,
.detach_dev = mtk_iommu_detach_device,
.map = mtk_iommu_map,
+ .map_atomic = mtk_iommu_map,
.unmap = mtk_iommu_unmap,
.flush_iotlb_all = mtk_iommu_iotlb_sync,
.iotlb_sync = mtk_iommu_iotlb_sync,
diff --git a/drivers/iommu/qcom_iommu.c b/drivers/iommu/qcom_iommu.c
index 8cdd3f059513..26100487642d 100644
--- a/drivers/iommu/qcom_iommu.c
+++ b/drivers/iommu/qcom_iommu.c
@@ -591,6 +591,7 @@ static const struct iommu_ops qcom_iommu_ops = {
.attach_dev = qcom_iommu_attach_dev,
.detach_dev = qcom_iommu_detach_dev,
.map = qcom_iommu_map,
+ .map_atomic = qcom_iommu_map,
.unmap = qcom_iommu_unmap,
.flush_iotlb_all = qcom_iommu_iotlb_sync,
.iotlb_sync = qcom_iommu_iotlb_sync,
diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 77d4bd93fe4b..d24bc2413d49 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -1124,6 +1124,7 @@ static const struct iommu_ops rk_iommu_ops = {
.attach_dev = rk_iommu_attach_device,
.detach_dev = rk_iommu_detach_device,
.map = rk_iommu_map,
+ .map_atomic = rk_iommu_map,
.unmap = rk_iommu_unmap,
.add_device = rk_iommu_add_device,
.remove_device = rk_iommu_remove_device,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index ffbbc7e39cee..75559918d9bd 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -166,6 +166,7 @@ struct iommu_resv_region {
* @attach_dev: attach device to an iommu domain
* @detach_dev: detach device from an iommu domain
* @map: map a physically contiguous memory region to an iommu domain
+ * @map_atomic: same as map but can be called from an atomic context
* @unmap: unmap a physically contiguous memory region from an iommu domain
* @flush_iotlb_all: Synchronously flush all hardware TLBs for this domain
* @iotlb_range_add: Add a given iova range to the flush queue for this domain
@@ -199,6 +200,8 @@ struct iommu_ops {
void (*detach_dev)(struct iommu_domain *domain, struct device *dev);
int (*map)(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot);
+ int (*map_atomic)(struct iommu_domain *domain, unsigned long iova,
+ phys_addr_t paddr, size_t size, int prot);
size_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
size_t size);
void (*flush_iotlb_all)(struct iommu_domain *domain);
@@ -295,12 +298,17 @@ extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
extern struct iommu_domain *iommu_get_dma_domain(struct device *dev);
extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot);
+extern int iommu_map_atomic(struct iommu_domain *domain, unsigned long iova,
+ phys_addr_t paddr, size_t size, int prot);
extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
size_t size);
extern size_t iommu_unmap_fast(struct iommu_domain *domain,
unsigned long iova, size_t size);
extern size_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
struct scatterlist *sg,unsigned int nents, int prot);
+extern size_t iommu_map_sg_atomic(struct iommu_domain *domain,
+ unsigned long iova, struct scatterlist *sg,
+ unsigned int nents, int prot);
extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova);
extern void iommu_set_fault_handler(struct iommu_domain *domain,
iommu_fault_handler_t handler, void *token);
@@ -469,6 +477,13 @@ static inline int iommu_map(struct iommu_domain *domain, unsigned long iova,
return -ENODEV;
}

+static inline int iommu_map_atomic(struct iommu_domain *domain,
+ unsigned long iova, phys_addr_t paddr,
+ size_t size, int prot)
+{
+ return -ENODEV;
+}
+
static inline size_t iommu_unmap(struct iommu_domain *domain,
unsigned long iova, size_t size)
{
@@ -488,6 +503,13 @@ static inline size_t iommu_map_sg(struct iommu_domain *domain,
return 0;
}

+static inline size_t iommu_map_sg_atomic(struct iommu_domain *domain,
+ unsigned long iova, struct scatterlist *sg,
+ unsigned int nents, int prot)
+{
+ return 0;
+}
+
static inline void iommu_flush_tlb_all(struct iommu_domain *domain)
{
}
--
2.17.1
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