Subject: + lib-genalloc-add-a-helper-function-for-dma-buffer-allocation.patch added to -mm tree
To: b42378@xxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 31 Oct 2013 14:27:04 -0700
The patch titled
Subject: lib/genalloc: add a helper function for DMA buffer allocation
has been added to the -mm tree. Its filename is
lib-genalloc-add-a-helper-function-for-dma-buffer-allocation.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-genalloc-add-a-helper-function-for-dma-buffer-allocation.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-genalloc-add-a-helper-function-for-dma-buffer-allocation.patch
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------------------------------------------------------
From: Nicolin Chen <b42378@xxxxxxxxxxxxx>
Subject: lib/genalloc: add a helper function for DMA buffer allocation
When using pool space for DMA buffer, there might be duplicated calling of
gen_pool_alloc() and gen_pool_virt_to_phys() in each implementation.
Thus it's better to add a simple helper function, a compatible one to the
common dma_alloc_coherent(), to save some code.
Signed-off-by: Nicolin Chen <b42378@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/genalloc.h | 2 ++
lib/genalloc.c | 28 ++++++++++++++++++++++++++++
2 files changed, 30 insertions(+)
diff -puN include/linux/genalloc.h~lib-genalloc-add-a-helper-function-for-dma-buffer-allocation include/linux/genalloc.h
--- a/include/linux/genalloc.h~lib-genalloc-add-a-helper-function-for-dma-buffer-allocation
+++ a/include/linux/genalloc.h
@@ -94,6 +94,8 @@ static inline int gen_pool_add(struct ge
}
extern void gen_pool_destroy(struct gen_pool *);
extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
+extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
+ dma_addr_t *dma);
extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
extern void gen_pool_for_each_chunk(struct gen_pool *,
void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
diff -puN lib/genalloc.c~lib-genalloc-add-a-helper-function-for-dma-buffer-allocation lib/genalloc.c
--- a/lib/genalloc.c~lib-genalloc-add-a-helper-function-for-dma-buffer-allocation
+++ a/lib/genalloc.c
@@ -313,6 +313,34 @@ retry:
EXPORT_SYMBOL(gen_pool_alloc);
/**
+ * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage
+ * @pool: pool to allocate from
+ * @size: number of bytes to allocate from the pool
+ * @dma: dma-view physical address
+ *
+ * Allocate the requested number of bytes from the specified pool.
+ * Uses the pool allocation function (with first-fit algorithm by default).
+ * Can not be used in NMI handler on architectures without
+ * NMI-safe cmpxchg implementation.
+ */
+void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
+{
+ unsigned long vaddr;
+
+ if (!pool)
+ return NULL;
+
+ vaddr = gen_pool_alloc(pool, size);
+ if (!vaddr)
+ return NULL;
+
+ *dma = gen_pool_virt_to_phys(pool, vaddr);
+
+ return (void *)vaddr;
+}
+EXPORT_SYMBOL(gen_pool_dma_alloc);
+
+/**
* gen_pool_free - free allocated special memory back to the pool
* @pool: pool to free to
* @addr: starting address of memory to free back to pool
_
Patches currently in -mm which might be from b42378@xxxxxxxxxxxxx are
lib-genalloc-add-a-helper-function-for-dma-buffer-allocation.patch
linux-next.patch
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