dma-mapping: remove the {alloc,free}_noncoherent methods

It turns out allowing non-contigous allocations here was a rather bad
idea, as we'll now need to define ways to get the pages for mmaping
or dma_buf sharing.  Revert this change and stick to the original
concept.  A different API for the use case of non-contigous allocations
will be added back later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Tested-by: Ricardo Ribalda <ribalda@chromium.org>:wq

diff --git a/Documentation/core-api/dma-api.rst b/Documentation/core-api/dma-api.rst
index 75cb757..e6d23f1 100644 (file)
--- a/Documentation/core-api/dma-api.rst
+++ b/Documentation/core-api/dma-api.rst
@@ -528,16 +528,14 @@ an I/O device, you should not be using this part of the API.
 
 ::
 
-       void *
-       dma_alloc_noncoherent(struct device *dev, size_t size,
-                       dma_addr_t *dma_handle, enum dma_data_direction dir,
-                       gfp_t gfp)
+       struct page *
+       dma_alloc_pages(struct device *dev, size_t size, dma_addr_t *dma_handle,
+                       enum dma_data_direction dir, gfp_t gfp)
 
-This routine allocates a region of <size> bytes of consistent memory.  It
-returns a pointer to the allocated region (in the processor's virtual address
-space) or NULL if the allocation failed.  The returned memory may or may not
-be in the kernel direct mapping.  Drivers must not call virt_to_page on
-the returned memory region.
+This routine allocates a region of <size> bytes of non-coherent memory.  It
+returns a pointer to first struct page for the region, or NULL if the
+allocation failed. The resulting struct page can be used for everything a
+struct page is suitable for.
 
 It also returns a <dma_handle> which may be cast to an unsigned integer the
 same width as the bus and given to the device as the DMA address base of
@@ -558,51 +556,33 @@ reused.
 ::
 
        void
-       dma_free_noncoherent(struct device *dev, size_t size, void *cpu_addr,
+       dma_free_pages(struct device *dev, size_t size, struct page *page,
                        dma_addr_t dma_handle, enum dma_data_direction dir)
 
-Free a region of memory previously allocated using dma_alloc_noncoherent().
-dev, size and dma_handle and dir must all be the same as those passed into
-dma_alloc_noncoherent().  cpu_addr must be the virtual address returned by
-dma_alloc_noncoherent().
+Free a region of memory previously allocated using dma_alloc_pages().
+dev, size, dma_handle and dir must all be the same as those passed into
+dma_alloc_pages().  page must be the pointer returned by dma_alloc_pages().
 
 ::
 
-       struct page *
-       dma_alloc_pages(struct device *dev, size_t size, dma_addr_t *dma_handle,
-                       enum dma_data_direction dir, gfp_t gfp)
-
-This routine allocates a region of <size> bytes of non-coherent memory.  It
-returns a pointer to first struct page for the region, or NULL if the
-allocation failed. The resulting struct page can be used for everything a
-struct page is suitable for.
-
-It also returns a <dma_handle> which may be cast to an unsigned integer the
-same width as the bus and given to the device as the DMA address base of
-the region.
-
-The dir parameter specified if data is read and/or written by the device,
-see dma_map_single() for details.
-
-The gfp parameter allows the caller to specify the ``GFP_`` flags (see
-kmalloc()) for the allocation, but rejects flags used to specify a memory
-zone such as GFP_DMA or GFP_HIGHMEM.
+       void *
+       dma_alloc_noncoherent(struct device *dev, size_t size,
+                       dma_addr_t *dma_handle, enum dma_data_direction dir,
+                       gfp_t gfp)
 
-Before giving the memory to the device, dma_sync_single_for_device() needs
-to be called, and before reading memory written by the device,
-dma_sync_single_for_cpu(), just like for streaming DMA mappings that are
-reused.
+This routine is a convenient wrapper around dma_alloc_pages that returns the
+kernel virtual address for the allocated memory instead of the page structure.
 
 ::
 
        void
-       dma_free_pages(struct device *dev, size_t size, struct page *page,
+       dma_free_noncoherent(struct device *dev, size_t size, void *cpu_addr,
                        dma_addr_t dma_handle, enum dma_data_direction dir)
 
-Free a region of memory previously allocated using dma_alloc_pages().
-dev, size and dma_handle and dir must all be the same as those passed into
-dma_alloc_noncoherent().  page must be the pointer returned by
-dma_alloc_pages().
+Free a region of memory previously allocated using dma_alloc_noncoherent().
+dev, size, dma_handle and dir must all be the same as those passed into
+dma_alloc_noncoherent().  cpu_addr must be the virtual address returned by
+dma_alloc_noncoherent().
 
 ::
 

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 4078358..255533f 100644 (file)
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1197,34 +1197,6 @@ static void *iommu_dma_alloc(struct device *dev, size_t size,
        return cpu_addr;
 }
 
-#ifdef CONFIG_DMA_REMAP
-static void *iommu_dma_alloc_noncoherent(struct device *dev, size_t size,
-               dma_addr_t *handle, enum dma_data_direction dir, gfp_t gfp)
-{
-       if (!gfpflags_allow_blocking(gfp)) {
-               struct page *page;
-
-               page = dma_common_alloc_pages(dev, size, handle, dir, gfp);
-               if (!page)
-                       return NULL;
-               return page_address(page);
-       }
-
-       return iommu_dma_alloc_remap(dev, size, handle, gfp | __GFP_ZERO,
-                                    PAGE_KERNEL, 0);
-}
-
-static void iommu_dma_free_noncoherent(struct device *dev, size_t size,
-               void *cpu_addr, dma_addr_t handle, enum dma_data_direction dir)
-{
-       __iommu_dma_unmap(dev, handle, size);
-       __iommu_dma_free(dev, size, cpu_addr);
-}
-#else
-#define iommu_dma_alloc_noncoherent            NULL
-#define iommu_dma_free_noncoherent             NULL
-#endif /* CONFIG_DMA_REMAP */
-
 static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
                void *cpu_addr, dma_addr_t dma_addr, size_t size,
                unsigned long attrs)
@@ -1295,8 +1267,6 @@ static const struct dma_map_ops iommu_dma_ops = {
        .free                   = iommu_dma_free,
        .alloc_pages            = dma_common_alloc_pages,
        .free_pages             = dma_common_free_pages,
-       .alloc_noncoherent      = iommu_dma_alloc_noncoherent,
-       .free_noncoherent       = iommu_dma_free_noncoherent,
        .mmap                   = iommu_dma_mmap,
        .get_sgtable            = iommu_dma_get_sgtable,
        .map_page               = iommu_dma_map_page,

diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 70fcd0f..11e0253 100644 (file)
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -22,11 +22,6 @@ struct dma_map_ops {
                        gfp_t gfp);
        void (*free_pages)(struct device *dev, size_t size, struct page *vaddr,
                        dma_addr_t dma_handle, enum dma_data_direction dir);
-       void *(*alloc_noncoherent)(struct device *dev, size_t size,
-                       dma_addr_t *dma_handle, enum dma_data_direction dir,
-                       gfp_t gfp);
-       void (*free_noncoherent)(struct device *dev, size_t size, void *vaddr,
-                       dma_addr_t dma_handle, enum dma_data_direction dir);
        int (*mmap)(struct device *, struct vm_area_struct *,
                        void *, dma_addr_t, size_t, unsigned long attrs);
 

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 2e49996..fbfa3f5 100644 (file)
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -263,10 +263,19 @@ struct page *dma_alloc_pages(struct device *dev, size_t size,
                dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
 void dma_free_pages(struct device *dev, size_t size, struct page *page,
                dma_addr_t dma_handle, enum dma_data_direction dir);
-void *dma_alloc_noncoherent(struct device *dev, size_t size,
-               dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
-void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
-               dma_addr_t dma_handle, enum dma_data_direction dir);
+
+static inline void *dma_alloc_noncoherent(struct device *dev, size_t size,
+               dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
+{
+       struct page *page = dma_alloc_pages(dev, size, dma_handle, dir, gfp);
+       return page ? page_address(page) : NULL;
+}
+
+static inline void dma_free_noncoherent(struct device *dev, size_t size,
+               void *vaddr, dma_addr_t dma_handle, enum dma_data_direction dir)
+{
+       dma_free_pages(dev, size, virt_to_page(vaddr), dma_handle, dir);
+}
 
 static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
                size_t size, enum dma_data_direction dir, unsigned long attrs)

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index f87a89d..68992e3 100644 (file)
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -515,46 +515,6 @@ void dma_free_pages(struct device *dev, size_t size, struct page *page,
 }
 EXPORT_SYMBOL_GPL(dma_free_pages);
 
-void *dma_alloc_noncoherent(struct device *dev, size_t size,
-               dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
-{
-       const struct dma_map_ops *ops = get_dma_ops(dev);
-       void *vaddr;
-
-       if (!ops || !ops->alloc_noncoherent) {
-               struct page *page;
-
-               page = dma_alloc_pages(dev, size, dma_handle, dir, gfp);
-               if (!page)
-                       return NULL;
-               return page_address(page);
-       }
-
-       size = PAGE_ALIGN(size);
-       vaddr = ops->alloc_noncoherent(dev, size, dma_handle, dir, gfp);
-       if (vaddr)
-               debug_dma_map_page(dev, virt_to_page(vaddr), 0, size, dir,
-                                  *dma_handle);
-       return vaddr;
-}
-EXPORT_SYMBOL_GPL(dma_alloc_noncoherent);
-
-void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
-               dma_addr_t dma_handle, enum dma_data_direction dir)
-{
-       const struct dma_map_ops *ops = get_dma_ops(dev);
-
-       if (!ops || !ops->free_noncoherent) {
-               dma_free_pages(dev, size, virt_to_page(vaddr), dma_handle, dir);
-               return;
-       }
-
-       size = PAGE_ALIGN(size);
-       debug_dma_unmap_page(dev, dma_handle, size, dir);
-       ops->free_noncoherent(dev, size, vaddr, dma_handle, dir);
-}
-EXPORT_SYMBOL_GPL(dma_free_noncoherent);
-
 int dma_supported(struct device *dev, u64 mask)
 {
        const struct dma_map_ops *ops = get_dma_ops(dev);