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lib/genalloc: add gen_pool_dma_zalloc() for zeroed DMA allocations 

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

Signed-off-by: Fredrik Noring <noring@nocrew.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Fredrik Noring 2019-05-29 13:28:39 +03:00 committed by Christoph Hellwig
parent dd3dcede9f
commit da83a72295
2 changed files with 29 additions and 1 deletions
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1
include/linux/genalloc.h
View File

@ -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 *);

29
lib/genalloc.c
View File

@ -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