Re: [PATCH 06/12] dma-direct: remove dma_direct_{alloc,free}_pages

[Robin Murphy]

On 2020-09-08 17:47, Christoph Hellwig wrote:

Just merge these helpers into the main dma_direct_{alloc,free} routines,
as the additional checks are always false for the two callers.

Reviewed-by: Robin Murphy <robin.mur...@arm.com>

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
  arch/x86/kernel/amd_gart_64.c |  6 +++---
  include/linux/dma-direct.h    |  4 ----
  kernel/dma/direct.c           | 39 ++++++++++++++---------------------
  kernel/dma/pool.c             |  2 +-
  4 files changed, 19 insertions(+), 32 deletions(-)

diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index bccc5357bffd6c..153374b996a279 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -467,7 +467,7 @@ gart_alloc_coherent(struct device *dev, size_t size, 
dma_addr_t *dma_addr,
  {
        void *vaddr;

- vaddr = dma_direct_alloc_pages(dev, size, dma_addr, flag, attrs);

+       vaddr = dma_direct_alloc(dev, size, dma_addr, flag, attrs);
        if (!vaddr ||
            !force_iommu || dev->coherent_dma_mask <= DMA_BIT_MASK(24))
                return vaddr;
@@ -479,7 +479,7 @@ gart_alloc_coherent(struct device *dev, size_t size, 
dma_addr_t *dma_addr,
                goto out_free;
        return vaddr;
  out_free:
-       dma_direct_free_pages(dev, size, vaddr, *dma_addr, attrs);
+       dma_direct_free(dev, size, vaddr, *dma_addr, attrs);
        return NULL;
  }

@@ -489,7 +489,7 @@ gart_free_coherent(struct device *dev, size_t size, void *vaddr,

                   dma_addr_t dma_addr, unsigned long attrs)
  {
        gart_unmap_page(dev, dma_addr, size, DMA_BIDIRECTIONAL, 0);
-       dma_direct_free_pages(dev, size, vaddr, dma_addr, attrs);
+       dma_direct_free(dev, size, vaddr, dma_addr, attrs);
  }

static int no_agp;

diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 95e3e28bd93f47..20eceb2e4f91f8 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -77,10 +77,6 @@ void *dma_direct_alloc(struct device *dev, size_t size, 
dma_addr_t *dma_handle,
                gfp_t gfp, unsigned long attrs);
  void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
                dma_addr_t dma_addr, unsigned long attrs);
-void *dma_direct_alloc_pages(struct device *dev, size_t size,
-               dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);
-void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
-               dma_addr_t dma_addr, unsigned long attrs);
  int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt,
                void *cpu_addr, dma_addr_t dma_addr, size_t size,
                unsigned long attrs);
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 949c1cbf08b2d5..1d564bea58571b 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -151,13 +151,18 @@ static struct page *__dma_direct_alloc_pages(struct 
device *dev, size_t size,
        return page;
  }

-void *dma_direct_alloc_pages(struct device *dev, size_t size,

+void *dma_direct_alloc(struct device *dev, size_t size,
                dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
  {
        struct page *page;
        void *ret;
        int err;

+ if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&

+           !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
+           dma_alloc_need_uncached(dev, attrs))
+               return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
+
        size = PAGE_ALIGN(size);

if (dma_should_alloc_from_pool(dev, gfp, attrs)) {

@@ -256,11 +261,18 @@ void *dma_direct_alloc_pages(struct device *dev, size_t 
size,
        return NULL;
  }

-void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,

-               dma_addr_t dma_addr, unsigned long attrs)
+void dma_direct_free(struct device *dev, size_t size,
+               void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
  {
        unsigned int page_order = get_order(size);

+ if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&

+           !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
+           dma_alloc_need_uncached(dev, attrs)) {
+               arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
+               return;
+       }
+
        /* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */
        if (dma_should_free_from_pool(dev, attrs) &&
            dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size)))
@@ -284,27 +296,6 @@ void dma_direct_free_pages(struct device *dev, size_t 
size, void *cpu_addr,
        dma_free_contiguous(dev, dma_direct_to_page(dev, dma_addr), size);
  }

-void *dma_direct_alloc(struct device *dev, size_t size,

-               dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
-{
-       if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
-           !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
-           dma_alloc_need_uncached(dev, attrs))
-               return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
-       return dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);
-}
-
-void dma_direct_free(struct device *dev, size_t size,
-               void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
-{
-       if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
-           !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
-           dma_alloc_need_uncached(dev, attrs))
-               arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
-       else
-               dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs);
-}
-
  #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
      defined(CONFIG_SWIOTLB)
  void dma_direct_sync_sg_for_device(struct device *dev,
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 1281c0f0442bc5..fe11643ff9cc7b 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -115,7 +115,7 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t 
pool_size,
  #endif
        /*
         * Memory in the atomic DMA pools must be unencrypted, the pools do not
-        * shrink so no re-encryption occurs in dma_direct_free_pages().
+        * shrink so no re-encryption occurs in dma_direct_free().
         */
        ret = set_memory_decrypted((unsigned long)page_to_virt(page),
                                   1 << order);