[PATCH v4 3/6] iommu: add iommu_default_dma_mode_get() helper

[Zhen Lei]

Add IOMMU_DMA_MODE_IS_LAZY() and IOMMU_DMA_MODE_IS_PASSTHROUGH() to make
the code looks cleaner.

There is no functional change, just prepare for the following patches.

Signed-off-by: Zhen Lei <thunder.leiz...@huawei.com>
---
 drivers/iommu/iommu.c | 12 ++++++++----
 include/linux/iommu.h | 11 +++++++++++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index b75e23a2ea08da8..876c0966db2481a 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -168,6 +168,11 @@ static int __init iommu_dma_mode_setup(char *str)
 }
 early_param("iommu.dma_mode", iommu_dma_mode_setup);
 
+int iommu_default_dma_mode_get(void)
+{
+       return iommu_default_dma_mode;
+}
+
 static ssize_t iommu_group_attr_show(struct kobject *kobj,
                                     struct attribute *__attr, char *buf)
 {
@@ -1109,9 +1114,8 @@ struct iommu_group *iommu_group_get_for_dev(struct device 
*dev)
         */
        if (!group->default_domain) {
                struct iommu_domain *dom;
-               int def_domain_type =
-                       (iommu_default_dma_mode == IOMMU_DMA_MODE_PASSTHROUGH)
-                       ? IOMMU_DOMAIN_IDENTITY : IOMMU_DOMAIN_DMA;
+               int def_domain_type = IOMMU_DMA_MODE_IS_PASSTHROUGH() \
+                               ? IOMMU_DOMAIN_IDENTITY : IOMMU_DOMAIN_DMA;
 
                dom = __iommu_domain_alloc(dev->bus, def_domain_type);
                if (!dom && def_domain_type != IOMMU_DOMAIN_DMA) {
@@ -1127,7 +1131,7 @@ struct iommu_group *iommu_group_get_for_dev(struct device 
*dev)
                if (!group->domain)
                        group->domain = dom;
 
-               if (dom && (iommu_default_dma_mode == IOMMU_DMA_MODE_LAZY)) {
+               if (dom && IOMMU_DMA_MODE_IS_LAZY()) {
                        int attr = 1;
                        iommu_domain_set_attr(dom,
                                              DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index c3f4e3416176496..1b35ae3f6382e4a 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -46,6 +46,10 @@
 #define IOMMU_DMA_MODE_STRICT          0x0
 #define IOMMU_DMA_MODE_LAZY            0x1
 #define IOMMU_DMA_MODE_PASSTHROUGH     0x2
+#define IOMMU_DMA_MODE_IS_LAZY() \
+               (iommu_default_dma_mode_get() == IOMMU_DMA_MODE_LAZY)
+#define IOMMU_DMA_MODE_IS_PASSTHROUGH() \
+               (iommu_default_dma_mode_get() == IOMMU_DMA_MODE_PASSTHROUGH)
 
 struct iommu_ops;
 struct iommu_group;
@@ -421,6 +425,8 @@ static inline void dev_iommu_fwspec_set(struct device *dev,
 int iommu_probe_device(struct device *dev);
 void iommu_release_device(struct device *dev);
 
+extern int iommu_default_dma_mode_get(void);
+
 #else /* CONFIG_IOMMU_API */
 
 struct iommu_ops {};
@@ -705,6 +711,11 @@ const struct iommu_ops *iommu_ops_from_fwnode(struct 
fwnode_handle *fwnode)
        return NULL;
 }
 
+static inline int iommu_default_dma_mode_get(void)
+{
+       return IOMMU_DMA_MODE_PASSTHROUGH;
+}
+
 #endif /* CONFIG_IOMMU_API */
 
 #ifdef CONFIG_IOMMU_DEBUGFS
-- 
1.8.3