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-rw-r--r--include/linux/scatterlist.h56
1 files changed, 47 insertions, 9 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index ecf87484814f..266754a55327 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -39,6 +39,12 @@ struct sg_table {
unsigned int orig_nents; /* original size of list */
};
+struct sg_append_table {
+ struct sg_table sgt; /* The scatter list table */
+ struct scatterlist *prv; /* last populated sge in the table */
+ unsigned int total_nents; /* Total entries in the table */
+};
+
/*
* Notes on SG table design.
*
@@ -280,19 +286,51 @@ typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t);
typedef void (sg_free_fn)(struct scatterlist *, unsigned int);
void __sg_free_table(struct sg_table *, unsigned int, unsigned int,
- sg_free_fn *);
+ sg_free_fn *, unsigned int);
void sg_free_table(struct sg_table *);
+void sg_free_append_table(struct sg_append_table *sgt);
int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int,
struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *);
int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
-struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt,
- struct page **pages, unsigned int n_pages, unsigned int offset,
- unsigned long size, unsigned int max_segment,
- struct scatterlist *prv, unsigned int left_pages,
- gfp_t gfp_mask);
-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);
+int sg_alloc_append_table_from_pages(struct sg_append_table *sgt,
+ struct page **pages, unsigned int n_pages,
+ unsigned int offset, unsigned long size,
+ unsigned int max_segment,
+ unsigned int left_pages, gfp_t gfp_mask);
+int sg_alloc_table_from_pages_segment(struct sg_table *sgt, struct page **pages,
+ unsigned int n_pages, unsigned int offset,
+ unsigned long size,
+ unsigned int max_segment, gfp_t gfp_mask);
+
+/**
+ * sg_alloc_table_from_pages - Allocate and initialize an sg table from
+ * an array of pages
+ * @sgt: The sg table header to use
+ * @pages: Pointer to an array of page pointers
+ * @n_pages: Number of pages in the pages array
+ * @offset: Offset from start of the first page to the start of a buffer
+ * @size: Number of valid bytes in the buffer (after offset)
+ * @gfp_mask: GFP allocation mask
+ *
+ * Description:
+ * Allocate and initialize an sg table from a list of pages. Contiguous
+ * ranges of the pages are squashed into a single scatterlist node. A user
+ * may provide an offset at a start and a size of valid data in a buffer
+ * specified by the page array. The returned sg table is released by
+ * sg_free_table.
+ *
+ * Returns:
+ * 0 on success, negative error on failure
+ */
+static inline 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)
+{
+ return sg_alloc_table_from_pages_segment(sgt, pages, n_pages, offset,
+ size, UINT_MAX, gfp_mask);
+}
#ifdef CONFIG_SGL_ALLOC
struct scatterlist *sgl_alloc_order(unsigned long long length,