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authorLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-22 19:11:06 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-22 19:11:06 -0700
commit69450bb5eb8e9df28281c62f98e971c9969dc4ff (patch)
tree85991e6e8b74cb08b5013fd7e419c3df67d23e35 /include
parente38f981758118d829cd40cfe9c09e3fa81e422aa (diff)
parentd6ec084200c37683278c821338f74ddf21ab80f5 (diff)
Merge branch 'sg' of git://git.kernel.dk/linux-2.6-block
* 'sg' of git://git.kernel.dk/linux-2.6-block: Add CONFIG_DEBUG_SG sg validation Change table chaining layout Update arch/ to use sg helpers Update swiotlb to use sg helpers Update net/ to use sg helpers Update fs/ to use sg helpers [SG] Update drivers to use sg helpers [SG] Update crypto/ to sg helpers [SG] Update block layer to use sg helpers [SG] Add helpers for manipulating SG entries
Diffstat (limited to 'include')
-rw-r--r--include/asm-alpha/scatterlist.h5
-rw-r--r--include/asm-arm/scatterlist.h5
-rw-r--r--include/asm-avr32/scatterlist.h5
-rw-r--r--include/asm-blackfin/scatterlist.h5
-rw-r--r--include/asm-cris/scatterlist.h5
-rw-r--r--include/asm-frv/scatterlist.h5
-rw-r--r--include/asm-h8300/scatterlist.h5
-rw-r--r--include/asm-ia64/scatterlist.h5
-rw-r--r--include/asm-m32r/scatterlist.h5
-rw-r--r--include/asm-m68k/scatterlist.h5
-rw-r--r--include/asm-m68knommu/scatterlist.h5
-rw-r--r--include/asm-mips/scatterlist.h5
-rw-r--r--include/asm-parisc/scatterlist.h5
-rw-r--r--include/asm-powerpc/scatterlist.h5
-rw-r--r--include/asm-s390/scatterlist.h5
-rw-r--r--include/asm-sh/scatterlist.h5
-rw-r--r--include/asm-sh64/scatterlist.h5
-rw-r--r--include/asm-sparc/scatterlist.h5
-rw-r--r--include/asm-sparc64/scatterlist.h5
-rw-r--r--include/asm-v850/scatterlist.h5
-rw-r--r--include/asm-x86/dma-mapping_32.h4
-rw-r--r--include/asm-x86/scatterlist_32.h5
-rw-r--r--include/asm-x86/scatterlist_64.h5
-rw-r--r--include/asm-xtensa/scatterlist.h5
-rw-r--r--include/linux/scatterlist.h202
25 files changed, 269 insertions, 52 deletions
diff --git a/include/asm-alpha/scatterlist.h b/include/asm-alpha/scatterlist.h
index 917365405e8..440747ca634 100644
--- a/include/asm-alpha/scatterlist.h
+++ b/include/asm-alpha/scatterlist.h
@@ -5,7 +5,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
unsigned int length;
diff --git a/include/asm-arm/scatterlist.h b/include/asm-arm/scatterlist.h
index de2f65eb42e..ca0a37d0340 100644
--- a/include/asm-arm/scatterlist.h
+++ b/include/asm-arm/scatterlist.h
@@ -5,7 +5,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page; /* buffer page */
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset; /* buffer offset */
dma_addr_t dma_address; /* dma address */
unsigned int length; /* length */
diff --git a/include/asm-avr32/scatterlist.h b/include/asm-avr32/scatterlist.h
index c6d5ce3b3a2..377320e3bd1 100644
--- a/include/asm-avr32/scatterlist.h
+++ b/include/asm-avr32/scatterlist.h
@@ -4,7 +4,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
dma_addr_t dma_address;
unsigned int length;
diff --git a/include/asm-blackfin/scatterlist.h b/include/asm-blackfin/scatterlist.h
index 60e07b92044..32128d53469 100644
--- a/include/asm-blackfin/scatterlist.h
+++ b/include/asm-blackfin/scatterlist.h
@@ -4,7 +4,10 @@
#include <linux/mm.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
dma_addr_t dma_address;
unsigned int length;
diff --git a/include/asm-cris/scatterlist.h b/include/asm-cris/scatterlist.h
index 4bdc44c4ac3..faff53ad1f9 100644
--- a/include/asm-cris/scatterlist.h
+++ b/include/asm-cris/scatterlist.h
@@ -2,11 +2,14 @@
#define __ASM_CRIS_SCATTERLIST_H
struct scatterlist {
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
char * address; /* Location data is to be transferred to */
unsigned int length;
/* The following is i386 highmem junk - not used by us */
- struct page * page; /* Location for highmem page, if any */
+ unsigned long page_link;
unsigned int offset;/* for highmem, page offset */
};
diff --git a/include/asm-frv/scatterlist.h b/include/asm-frv/scatterlist.h
index 8e827fa853f..f7da007b763 100644
--- a/include/asm-frv/scatterlist.h
+++ b/include/asm-frv/scatterlist.h
@@ -22,7 +22,10 @@
* and that's it. There's no excuse for not highmem enabling YOUR driver. /jens
*/
struct scatterlist {
- struct page *page; /* Location for highmem page, if any */
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset; /* for highmem, page offset */
dma_addr_t dma_address;
diff --git a/include/asm-h8300/scatterlist.h b/include/asm-h8300/scatterlist.h
index 985fdf54eac..d3ecdd87ac9 100644
--- a/include/asm-h8300/scatterlist.h
+++ b/include/asm-h8300/scatterlist.h
@@ -4,7 +4,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
dma_addr_t dma_address;
unsigned int length;
diff --git a/include/asm-ia64/scatterlist.h b/include/asm-ia64/scatterlist.h
index 7d5234d5031..d6f57874041 100644
--- a/include/asm-ia64/scatterlist.h
+++ b/include/asm-ia64/scatterlist.h
@@ -9,7 +9,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
unsigned int length; /* buffer length */
diff --git a/include/asm-m32r/scatterlist.h b/include/asm-m32r/scatterlist.h
index 352415ff5eb..1ed372c73d0 100644
--- a/include/asm-m32r/scatterlist.h
+++ b/include/asm-m32r/scatterlist.h
@@ -4,9 +4,12 @@
#include <asm/types.h>
struct scatterlist {
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
char * address; /* Location data is to be transferred to, NULL for
* highmem page */
- struct page * page; /* Location for highmem page, if any */
+ unsigned long page_link;
unsigned int offset;/* for highmem, page offset */
dma_addr_t dma_address;
diff --git a/include/asm-m68k/scatterlist.h b/include/asm-m68k/scatterlist.h
index 24887a2d9c7..d3a7a0edfec 100644
--- a/include/asm-m68k/scatterlist.h
+++ b/include/asm-m68k/scatterlist.h
@@ -4,7 +4,10 @@
#include <linux/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
unsigned int length;
diff --git a/include/asm-m68knommu/scatterlist.h b/include/asm-m68knommu/scatterlist.h
index 4da79d3d3f3..10942840e88 100644
--- a/include/asm-m68knommu/scatterlist.h
+++ b/include/asm-m68knommu/scatterlist.h
@@ -5,7 +5,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
dma_addr_t dma_address;
unsigned int length;
diff --git a/include/asm-mips/scatterlist.h b/include/asm-mips/scatterlist.h
index 7af104c95b2..83d69fe17c9 100644
--- a/include/asm-mips/scatterlist.h
+++ b/include/asm-mips/scatterlist.h
@@ -4,7 +4,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page * page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
dma_addr_t dma_address;
unsigned int length;
diff --git a/include/asm-parisc/scatterlist.h b/include/asm-parisc/scatterlist.h
index e7211c74844..cd3cfdf8228 100644
--- a/include/asm-parisc/scatterlist.h
+++ b/include/asm-parisc/scatterlist.h
@@ -5,7 +5,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
unsigned int length;
diff --git a/include/asm-powerpc/scatterlist.h b/include/asm-powerpc/scatterlist.h
index b075f619c3b..fcf7d55afe4 100644
--- a/include/asm-powerpc/scatterlist.h
+++ b/include/asm-powerpc/scatterlist.h
@@ -14,7 +14,10 @@
#include <asm/dma.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
unsigned int length;
diff --git a/include/asm-s390/scatterlist.h b/include/asm-s390/scatterlist.h
index a43b3afc5e2..29ec8e28c8d 100644
--- a/include/asm-s390/scatterlist.h
+++ b/include/asm-s390/scatterlist.h
@@ -2,7 +2,10 @@
#define _ASMS390_SCATTERLIST_H
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
unsigned int length;
};
diff --git a/include/asm-sh/scatterlist.h b/include/asm-sh/scatterlist.h
index b9ae53c3836..a7d0d1856a9 100644
--- a/include/asm-sh/scatterlist.h
+++ b/include/asm-sh/scatterlist.h
@@ -4,7 +4,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page * page; /* Location for highmem page, if any */
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;/* for highmem, page offset */
dma_addr_t dma_address;
unsigned int length;
diff --git a/include/asm-sh64/scatterlist.h b/include/asm-sh64/scatterlist.h
index 1c723f2d7a9..5109251970e 100644
--- a/include/asm-sh64/scatterlist.h
+++ b/include/asm-sh64/scatterlist.h
@@ -14,7 +14,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page * page; /* Location for highmem page, if any */
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;/* for highmem, page offset */
dma_addr_t dma_address;
unsigned int length;
diff --git a/include/asm-sparc/scatterlist.h b/include/asm-sparc/scatterlist.h
index 4055af90ad7..e08d3d775b0 100644
--- a/include/asm-sparc/scatterlist.h
+++ b/include/asm-sparc/scatterlist.h
@@ -5,7 +5,10 @@
#include <linux/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
unsigned int length;
diff --git a/include/asm-sparc64/scatterlist.h b/include/asm-sparc64/scatterlist.h
index 703c5bbe6c8..6df23f070b1 100644
--- a/include/asm-sparc64/scatterlist.h
+++ b/include/asm-sparc64/scatterlist.h
@@ -6,7 +6,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
unsigned int length;
diff --git a/include/asm-v850/scatterlist.h b/include/asm-v850/scatterlist.h
index 56f402920db..02d27b3fb06 100644
--- a/include/asm-v850/scatterlist.h
+++ b/include/asm-v850/scatterlist.h
@@ -17,7 +17,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned offset;
dma_addr_t dma_address;
unsigned length;
diff --git a/include/asm-x86/dma-mapping_32.h b/include/asm-x86/dma-mapping_32.h
index 6a2d26cb5da..55f01bd9e55 100644
--- a/include/asm-x86/dma-mapping_32.h
+++ b/include/asm-x86/dma-mapping_32.h
@@ -45,9 +45,9 @@ dma_map_sg(struct device *dev, struct scatterlist *sglist, int nents,
WARN_ON(nents == 0 || sglist[0].length == 0);
for_each_sg(sglist, sg, nents, i) {
- BUG_ON(!sg->page);
+ BUG_ON(!sg_page(sg));
- sg->dma_address = page_to_phys(sg->page) + sg->offset;
+ sg->dma_address = sg_phys(sg);
}
flush_write_buffers();
diff --git a/include/asm-x86/scatterlist_32.h b/include/asm-x86/scatterlist_32.h
index bd5164aa8f6..0e7d997a34b 100644
--- a/include/asm-x86/scatterlist_32.h
+++ b/include/asm-x86/scatterlist_32.h
@@ -4,7 +4,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
dma_addr_t dma_address;
unsigned int length;
diff --git a/include/asm-x86/scatterlist_64.h b/include/asm-x86/scatterlist_64.h
index ef3986ba4b7..1847c72befe 100644
--- a/include/asm-x86/scatterlist_64.h
+++ b/include/asm-x86/scatterlist_64.h
@@ -4,7 +4,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
unsigned int length;
dma_addr_t dma_address;
diff --git a/include/asm-xtensa/scatterlist.h b/include/asm-xtensa/scatterlist.h
index ca337a29429..810080bb0a2 100644
--- a/include/asm-xtensa/scatterlist.h
+++ b/include/asm-xtensa/scatterlist.h
@@ -14,7 +14,10 @@
#include <asm/types.h>
struct scatterlist {
- struct page *page;
+#ifdef CONFIG_DEBUG_SG
+ unsigned long sg_magic;
+#endif
+ unsigned long page_link;
unsigned int offset;
dma_addr_t dma_address;
unsigned int length;
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 2dc7464cce5..42daf5e1526 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -4,47 +4,95 @@
#include <asm/scatterlist.h>
#include <linux/mm.h>
#include <linux/string.h>
+#include <asm/io.h>
+/*
+ * Notes on SG table design.
+ *
+ * Architectures must provide an unsigned long page_link field in the
+ * scatterlist struct. We use that to place the page pointer AND encode
+ * information about the sg table as well. The two lower bits are reserved
+ * for this information.
+ *
+ * If bit 0 is set, then the page_link contains a pointer to the next sg
+ * table list. Otherwise the next entry is at sg + 1.
+ *
+ * If bit 1 is set, then this sg entry is the last element in a list.
+ *
+ * See sg_next().
+ *
+ */
+
+#define SG_MAGIC 0x87654321
+
+/**
+ * sg_set_page - Set sg entry to point at given page
+ * @sg: SG entry
+ * @page: The page
+ *
+ * Description:
+ * Use this function to set an sg entry pointing at a page, never assign
+ * the page directly. We encode sg table information in the lower bits
+ * of the page pointer. See sg_page() for looking up the page belonging
+ * to an sg entry.
+ *
+ **/
+static inline void sg_set_page(struct scatterlist *sg, struct page *page)
+{
+ 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;
+}
+
+#define sg_page(sg) ((struct page *) ((sg)->page_link & ~0x3))
+
+/**
+ * sg_set_buf - Set sg entry to point at given data
+ * @sg: SG entry
+ * @buf: Data
+ * @buflen: Data length
+ *
+ **/
static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
unsigned int buflen)
{
- sg->page = virt_to_page(buf);
+ sg_set_page(sg, virt_to_page(buf));
sg->offset = offset_in_page(buf);
sg->length = buflen;
}
-static inline void sg_init_one(struct scatterlist *sg, const void *buf,
- unsigned int buflen)
-{
- memset(sg, 0, sizeof(*sg));
- sg_set_buf(sg, buf, buflen);
-}
-
/*
* We overload the LSB of the page pointer to indicate whether it's
* a valid sg entry, or whether it points to the start of a new scatterlist.
* Those low bits are there for everyone! (thanks mason :-)
*/
-#define sg_is_chain(sg) ((unsigned long) (sg)->page & 0x01)
+#define sg_is_chain(sg) ((sg)->page_link & 0x01)
+#define sg_is_last(sg) ((sg)->page_link & 0x02)
#define sg_chain_ptr(sg) \
- ((struct scatterlist *) ((unsigned long) (sg)->page & ~0x01))
+ ((struct scatterlist *) ((sg)->page_link & ~0x03))
/**
* sg_next - return the next scatterlist entry in a list
* @sg: The current sg entry
*
- * Usually the next entry will be @sg@ + 1, but if this sg element is part
- * of a chained scatterlist, it could jump to the start of a new
- * scatterlist array.
- *
- * Note that the caller must ensure that there are further entries after
- * the current entry, this function will NOT return NULL for an end-of-list.
+ * Description:
+ * Usually the next entry will be @sg@ + 1, but if this sg element is part
+ * of a chained scatterlist, it could jump to the start of a new
+ * scatterlist array.
*
- */
+ **/
static inline struct scatterlist *sg_next(struct scatterlist *sg)
{
- sg++;
+#ifdef CONFIG_DEBUG_SG
+ BUG_ON(sg->sg_magic != SG_MAGIC);
+#endif
+ if (sg_is_last(sg))
+ return NULL;
+ sg++;
if (unlikely(sg_is_chain(sg)))
sg = sg_chain_ptr(sg);
@@ -62,14 +110,15 @@ static inline struct scatterlist *sg_next(struct scatterlist *sg)
* @sgl: First entry in the scatterlist
* @nents: Number of entries in the scatterlist
*
- * Should only be used casually, it (currently) scan the entire list
- * to get the last entry.
+ * Description:
+ * Should only be used casually, it (currently) scan the entire list
+ * to get the last entry.
*
- * Note that the @sgl@ pointer passed in need not be the first one,
- * the important bit is that @nents@ denotes the number of entries that
- * exist from @sgl@.
+ * Note that the @sgl@ pointer passed in need not be the first one,
+ * the important bit is that @nents@ denotes the number of entries that
+ * exist from @sgl@.
*
- */
+ **/
static inline struct scatterlist *sg_last(struct scatterlist *sgl,
unsigned int nents)
{
@@ -83,6 +132,10 @@ static inline struct scatterlist *sg_last(struct scatterlist *sgl,
ret = sg;
#endif
+#ifdef CONFIG_DEBUG_SG
+ BUG_ON(sgl[0].sg_magic != SG_MAGIC);
+ BUG_ON(!sg_is_last(ret));
+#endif
return ret;
}
@@ -92,16 +145,111 @@ static inline struct scatterlist *sg_last(struct scatterlist *sgl,
* @prv_nents: Number of entries in prv
* @sgl: Second scatterlist
*
- * Links @prv@ and @sgl@ together, to form a longer scatterlist.
+ * Description:
+ * Links @prv@ and @sgl@ together, to form a longer scatterlist.
*
- */
+ **/
static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
struct scatterlist *sgl)
{
#ifndef ARCH_HAS_SG_CHAIN
BUG();
#endif
- prv[prv_nents - 1].page = (struct page *) ((unsigned long) sgl | 0x01);
+ prv[prv_nents - 1].page_link = (unsigned long) sgl | 0x01;
+}
+
+/**
+ * sg_mark_end - Mark the end of the scatterlist
+ * @sgl: Scatterlist
+ * @nents: Number of entries in sgl
+ *
+ * Description:
+ * Marks the last entry as the termination point for sg_next()
+ *
+ **/
+static inline void sg_mark_end(struct scatterlist *sgl, unsigned int nents)
+{
+ sgl[nents - 1].page_link = 0x02;
+}
+
+static inline void __sg_mark_end(struct scatterlist *sg)
+{
+ sg->page_link |= 0x02;
+}
+
+/**
+ * sg_init_one - Initialize a single entry sg list
+ * @sg: SG entry
+ * @buf: Virtual address for IO
+ * @buflen: IO length
+ *
+ * Notes:
+ * This should not be used on a single entry that is part of a larger
+ * table. Use sg_init_table() for that.
+ *
+ **/
+static inline void sg_init_one(struct scatterlist *sg, const void *buf,
+ unsigned int buflen)
+{
+ memset(sg, 0, sizeof(*sg));
+#ifdef CONFIG_DEBUG_SG
+ sg->sg_magic = SG_MAGIC;
+#endif
+ sg_mark_end(sg, 1);
+ sg_set_buf(sg, buf, buflen);
+}
+
+/**
+ * sg_init_table - Initialize SG table
+ * @sgl: The SG table
+ * @nents: Number of entries in table
+ *
+ * Notes:
+ * If this is part of a chained sg table, sg_mark_end() should be
+ * used only on the last table part.
+ *
+ **/
+static inline void sg_init_table(struct scatterlist *sgl, unsigned int nents)
+{
+ memset(sgl, 0, sizeof(*sgl) * nents);
+ sg_mark_end(sgl, nents);
+#ifdef CONFIG_DEBUG_SG
+ {
+ int i;
+ for (i = 0; i < nents; i++)
+ sgl[i].sg_magic = SG_MAGIC;
+ }
+#endif
+}
+
+/**
+ * sg_phys - Return physical address of an sg entry
+ * @sg: SG entry
+ *
+ * Description:
+ * This calls page_to_phys() on the page in this sg entry, and adds the
+ * sg offset. The caller must know that it is legal to call page_to_phys()
+ * on the sg page.
+ *
+ **/
+static inline unsigned long sg_phys(struct scatterlist *sg)
+{
+ return page_to_phys(sg_page(sg)) + sg->offset;
+}
+
+/**
+ * sg_virt - Return virtual address of an sg entry
+ * @sg: SG entry
+ *
+ * Description:
+ * This calls page_address() on the page in this sg entry, and adds the
+ * sg offset. The caller must know that the sg page has a valid virtual
+ * mapping.
+ *
+ **/
+static inline void *sg_virt(struct scatterlist *sg)
+{
+ return page_address(sg_page(sg)) + sg->offset;
}
#endif /* _LINUX_SCATTERLIST_H */