#ifndef _LINUX_SCATTERLIST_H
#define _LINUX_SCATTERLIST_H
+#include <asm/types.h>
#include <asm/scatterlist.h>
#include <linux/mm.h>
#include <linux/string.h>
#define SG_MAGIC 0x87654321
+/**
+ * sg_assign_page - Assign a given page to an SG entry
+ * @sg: SG entry
+ * @page: The page
+ *
+ * Description:
+ * Assign page to sg entry. Also see sg_set_page(), the most commonly used
+ * variant.
+ *
+ **/
+static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
+{
+ unsigned long page_link = sg->page_link & 0x3;
+
+ /*
+ * In order for the low bit stealing approach to work, pages
+ * must be aligned at a 32-bit boundary as a minimum.
+ */
+ BUG_ON((unsigned long) page & 0x03);
+#ifdef CONFIG_DEBUG_SG
+ BUG_ON(sg->sg_magic != SG_MAGIC);
+#endif
+ sg->page_link = page_link | (unsigned long) page;
+}
+
/**
* sg_set_page - Set sg entry to point at given page
* @sg: SG entry
* @page: The page
+ * @len: Length of data
+ * @offset: Offset into page
*
* Description:
* Use this function to set an sg entry pointing at a page, never assign
* to an sg entry.
*
**/
-static inline void sg_set_page(struct scatterlist *sg, struct page *page)
+static inline void sg_set_page(struct scatterlist *sg, struct page *page,
+ unsigned int len, unsigned int offset)
{
- unsigned long page_link = sg->page_link & 0x3;
-
-#ifdef CONFIG_DEBUG_SG
- BUG_ON(sg->sg_magic != SG_MAGIC);
-#endif
- sg->page_link = page_link | (unsigned long) page;
+ sg_assign_page(sg, page);
+ sg->offset = offset;
+ sg->length = len;
}
#define sg_page(sg) ((struct page *) ((sg)->page_link & ~0x3))
static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
unsigned int buflen)
{
- sg_set_page(sg, virt_to_page(buf));
- sg->offset = offset_in_page(buf);
- sg->length = buflen;
+ sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
}
/*
* on the sg page.
*
**/
-static inline unsigned long sg_phys(struct scatterlist *sg)
+static inline dma_addr_t sg_phys(struct scatterlist *sg)
{
return page_to_phys(sg_page(sg)) + sg->offset;
}