diff options
| -rw-r--r-- | include/linux/scatterlist.h | 10 | ||||
| -rw-r--r-- | lib/Kconfig | 4 | ||||
| -rw-r--r-- | lib/scatterlist.c | 105 |
3 files changed, 119 insertions, 0 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index b7c83254c566..b8a7c1d1dbe3 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -276,6 +276,16 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, gfp_t gfp_mask); +#ifdef CONFIG_SGL_ALLOC +struct scatterlist *sgl_alloc_order(unsigned long long length, + unsigned int order, bool chainable, + gfp_t gfp, unsigned int *nent_p); +struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, + unsigned int *nent_p); +void sgl_free_order(struct scatterlist *sgl, int order); +void sgl_free(struct scatterlist *sgl); +#endif /* CONFIG_SGL_ALLOC */ + size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, size_t buflen, off_t skip, bool to_buffer); diff --git a/lib/Kconfig b/lib/Kconfig index c5e84fbcb30b..4dd5c11366f9 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -409,6 +409,10 @@ config HAS_DMA depends on !NO_DMA default y +config SGL_ALLOC + bool + default n + config DMA_NOOP_OPS bool depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT) diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 7c1c55f7daaa..9afc9b432083 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -474,6 +474,111 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, } EXPORT_SYMBOL(sg_alloc_table_from_pages); +#ifdef CONFIG_SGL_ALLOC + +/** + * sgl_alloc_order - allocate a scatterlist and its pages + * @length: Length in bytes of the scatterlist. Must be at least one + * @order: Second argument for alloc_pages() + * @chainable: Whether or not to allocate an extra element in the scatterlist + * for scatterlist chaining purposes + * @gfp: Memory allocation flags + * @nent_p: [out] Number of entries in the scatterlist that have pages + * + * Returns: A pointer to an initialized scatterlist or %NULL upon failure. + */ +struct scatterlist *sgl_alloc_order(unsigned long long length, + unsigned int order, bool chainable, + gfp_t gfp, unsigned int *nent_p) +{ + struct scatterlist *sgl, *sg; + struct page *page; + unsigned int nent, nalloc; + u32 elem_len; + + nent = round_up(length, PAGE_SIZE << order) >> (PAGE_SHIFT + order); + /* Check for integer overflow */ + if (length > (nent << (PAGE_SHIFT + order))) + return NULL; + nalloc = nent; + if (chainable) { + /* Check for integer overflow */ + if (nalloc + 1 < nalloc) + return NULL; + nalloc++; + } + sgl = kmalloc_array(nalloc, sizeof(struct scatterlist), + (gfp & ~GFP_DMA) | __GFP_ZERO); + if (!sgl) + return NULL; + + sg_init_table(sgl, nent); + sg = sgl; + while (length) { + elem_len = min_t(u64, length, PAGE_SIZE << order); + page = alloc_pages(gfp, order); + if (!page) { + sgl_free(sgl); + return NULL; + } + + sg_set_page(sg, page, elem_len, 0); + length -= elem_len; + sg = sg_next(sg); + } + WARN_ON_ONCE(sg); + if (nent_p) + *nent_p = nent; + return sgl; +} +EXPORT_SYMBOL(sgl_alloc_order); + +/** + * sgl_alloc - allocate a scatterlist and its pages + * @length: Length in bytes of the scatterlist + * @gfp: Memory allocation flags + * @nent_p: [out] Number of entries in the scatterlist + * + * Returns: A pointer to an initialized scatterlist or %NULL upon failure. + */ +struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, + unsigned int *nent_p) +{ + return sgl_alloc_order(length, 0, false, gfp, nent_p); +} +EXPORT_SYMBOL(sgl_alloc); + +/** + * sgl_free_order - free a scatterlist and its pages + * @sgl: Scatterlist with one or more elements + * @order: Second argument for __free_pages() + */ +void sgl_free_order(struct scatterlist *sgl, int order) +{ + struct scatterlist *sg; + struct page *page; + + for (sg = sgl; sg; sg = sg_next(sg)) { + page = sg_page(sg); + if (page) + __free_pages(page, order); + } + kfree(sgl); +} +EXPORT_SYMBOL(sgl_free_order); + +/** + * sgl_free - free a scatterlist and its pages + * @sgl: Scatterlist with one or more elements + */ +void sgl_free(struct scatterlist *sgl) +{ + sgl_free_order(sgl, 0); +} +EXPORT_SYMBOL(sgl_free); + +#endif /* CONFIG_SGL_ALLOC */ + void __sg_page_iter_start(struct sg_page_iter *piter, struct scatterlist *sglist, unsigned int nents, unsigned long pgoffset) |