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Subject[PATCH v5 1/5] lib/genalloc.c: Add gen_pool_dma_zalloc() for zeroed DMA allocations
Date
From: Fredrik Noring <noring@nocrew.org>

gen_pool_dma_zalloc() is a zeroed memory variant of gen_pool_dma_alloc().
Document return values of both, and indicate NULL as a "%NULL" constant.

Signed-off-by: Fredrik Noring <noring@nocrew.org>
---
include/linux/genalloc.h | 1 +
lib/genalloc.c | 29 ++++++++++++++++++++++++++++-
2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
index dd0a452373e7..6c62eeca754f 100644
--- a/include/linux/genalloc.h
+++ b/include/linux/genalloc.h
@@ -121,6 +121,7 @@ extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t,
genpool_algo_t algo, void *data);
extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
dma_addr_t *dma);
+void *gen_pool_dma_zalloc(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 --git a/lib/genalloc.c b/lib/genalloc.c
index 7e85d1e37a6e..5db43476a19b 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -337,12 +337,14 @@ EXPORT_SYMBOL(gen_pool_alloc_algo);
* 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 return value. Use NULL if unneeded.
+ * @dma: dma-view physical address return value. Use %NULL if unneeded.
*
* 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.
+ *
+ * Return: virtual address of the allocated memory, or %NULL on failure
*/
void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
{
@@ -362,6 +364,31 @@ void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
}
EXPORT_SYMBOL(gen_pool_dma_alloc);

+/**
+ * gen_pool_dma_zalloc - allocate special zeroed 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 return value. Use %NULL if unneeded.
+ *
+ * Allocate the requested number of zeroed 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.
+ *
+ * Return: virtual address of the allocated zeroed memory, or %NULL on failure
+ */
+void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
+{
+ void *vaddr = gen_pool_dma_alloc(pool, size, dma);
+
+ if (vaddr)
+ memset(vaddr, 0, size);
+
+ return vaddr;
+}
+EXPORT_SYMBOL(gen_pool_dma_zalloc);
+
/**
* gen_pool_free - free allocated special memory back to the pool
* @pool: pool to free to
--
2.17.1
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