Re: [PATCH 6/7] dma-mapping: make the global coherent pool conditional

Only build the code to support the global coherent pool if support for
it is enabled.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Dillon Min <redacted>
---
 include/linux/dma-map-ops.h | 18 +++++++-------
 kernel/dma/coherent.c       | 47 ++++++++++++++++++++-----------------
 2 files changed, 35 insertions(+), 30 deletions(-)

diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 7e49bb86a0c0..9b79aa4dd300 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h

@@ -170,13 +170,6 @@ int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
 int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr);
 int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
                void *cpu_addr, size_t size, int *ret);
-
-void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
-               dma_addr_t *dma_handle);
-int dma_release_from_global_coherent(int order, void *vaddr);
-int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *cpu_addr,
-               size_t size, int *ret);
-int dma_init_global_coherent(phys_addr_t phys_addr, size_t size);
 #else
 static inline int dma_declare_coherent_memory(struct device *dev,
                phys_addr_t phys_addr, dma_addr_t device_addr, size_t size)

@@ -186,7 +179,16 @@ static inline int dma_declare_coherent_memory(struct device *dev,
 #define dma_alloc_from_dev_coherent(dev, size, handle, ret) (0)
 #define dma_release_from_dev_coherent(dev, order, vaddr) (0)
 #define dma_mmap_from_dev_coherent(dev, vma, vaddr, order, ret) (0)
+#endif /* CONFIG_DMA_DECLARE_COHERENT */

+#ifdef CONFIG_DMA_GLOBAL_POOL
+void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
+               dma_addr_t *dma_handle);
+int dma_release_from_global_coherent(int order, void *vaddr);
+int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *cpu_addr,
+               size_t size, int *ret);
+int dma_init_global_coherent(phys_addr_t phys_addr, size_t size);
+#else
 static inline void *dma_alloc_from_global_coherent(struct device *dev,
                ssize_t size, dma_addr_t *dma_handle)
 {

@@ -201,7 +203,7 @@ static inline int dma_mmap_from_global_coherent(struct vm_area_struct *vma,
 {
        return 0;
 }
-#endif /* CONFIG_DMA_DECLARE_COHERENT */
+#endif /* CONFIG_DMA_GLOBAL_POOL */

 /*
  * This is the actual return value from the ->alloc_noncontiguous method.

diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index 160d4e246ecb..c05408902a68 100644
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c

@@ -20,8 +20,6 @@ struct dma_coherent_mem {
        bool            use_dev_dma_pfn_offset;
 };

-static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
-
 static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
 {
        if (dev && dev->dma_mem)

@@ -191,16 +189,6 @@ int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
        return 1;
 }

-void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
-                                    dma_addr_t *dma_handle)
-{
-       if (!dma_coherent_default_memory)
-               return NULL;
-
-       return __dma_alloc_from_coherent(dev, dma_coherent_default_memory, size,
-                                        dma_handle);
-}
-
 static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
                                       int order, void *vaddr)
 {

@@ -236,15 +224,6 @@ int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
        return __dma_release_from_coherent(mem, order, vaddr);
 }

-int dma_release_from_global_coherent(int order, void *vaddr)
-{
-       if (!dma_coherent_default_memory)
-               return 0;
-
-       return __dma_release_from_coherent(dma_coherent_default_memory, order,
-                       vaddr);
-}
-
 static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
                struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
 {

@@ -290,6 +269,28 @@ int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
        return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
 }

+#ifdef CONFIG_DMA_GLOBAL_POOL
+static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
+
+void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
+                                    dma_addr_t *dma_handle)
+{
+       if (!dma_coherent_default_memory)
+               return NULL;
+
+       return __dma_alloc_from_coherent(dev, dma_coherent_default_memory, size,
+                                        dma_handle);
+}
+
+int dma_release_from_global_coherent(int order, void *vaddr)
+{
+       if (!dma_coherent_default_memory)
+               return 0;
+
+       return __dma_release_from_coherent(dma_coherent_default_memory, order,
+                       vaddr);
+}
+
 int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
                                   size_t size, int *ret)
 {

@@ -311,6 +312,7 @@ int dma_init_global_coherent(phys_addr_t phys_addr, size_t size)
        pr_info("DMA: default coherent area is set\n");
        return 0;
 }
+#endif /* CONFIG_DMA_GLOBAL_POOL */

 /*
  * Support for reserved memory regions defined in device tree

@@ -377,6 +379,7 @@ static int __init rmem_dma_setup(struct reserved_mem *rmem)
        return 0;
 }

+#ifdef CONFIG_DMA_GLOBAL_POOL
 static int __init dma_init_reserved_memory(void)
 {
        if (!dma_reserved_default_memory)

@@ -384,8 +387,8 @@ static int __init dma_init_reserved_memory(void)
        return dma_init_global_coherent(dma_reserved_default_memory->base,
                                        dma_reserved_default_memory->size);