Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus

[linux-2.6-omap-h63xx.git] / include / linux / scatterlist.h

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 32326c293d7bfbd0c9fe318ce4f5143258bed65a..e3ff21dbac536f11d7f62be1dae027d37466b465 100644 (file)
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -26,6 +26,16 @@
 
 #define SG_MAGIC       0x87654321
 
+/*
+ * 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)                ((sg)->page_link & 0x01)
+#define sg_is_last(sg)         ((sg)->page_link & 0x02)
+#define sg_chain_ptr(sg)       \
+       ((struct scatterlist *) ((sg)->page_link & ~0x03))
+
 /**
  * sg_assign_page - Assign a given page to an SG entry
  * @sg:                    SG entry
@@ -47,6 +57,7 @@ static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
        BUG_ON((unsigned long) page & 0x03);
 #ifdef CONFIG_DEBUG_SG
        BUG_ON(sg->sg_magic != SG_MAGIC);
+       BUG_ON(sg_is_chain(sg));
 #endif
        sg->page_link = page_link | (unsigned long) page;
 }
@@ -73,7 +84,14 @@ static inline void sg_set_page(struct scatterlist *sg, struct page *page,
        sg->length = len;
 }
 
-#define sg_page(sg)    ((struct page *) ((sg)->page_link & ~0x3))
+static inline struct page *sg_page(struct scatterlist *sg)
+{
+#ifdef CONFIG_DEBUG_SG
+       BUG_ON(sg->sg_magic != SG_MAGIC);
+       BUG_ON(sg_is_chain(sg));
+#endif
+       return (struct page *)((sg)->page_link & ~0x3);
+}
 
 /**
  * sg_set_buf - Set sg entry to point at given data
@@ -88,16 +106,6 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
        sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
 }
 
-/*
- * 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)                ((sg)->page_link & 0x01)
-#define sg_is_last(sg)         ((sg)->page_link & 0x02)
-#define sg_chain_ptr(sg)       \
-       ((struct scatterlist *) ((sg)->page_link & ~0x03))
-
 /**
  * sg_next - return the next scatterlist entry in a list
  * @sg:                The current sg entry
@@ -179,6 +187,13 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
 #ifndef ARCH_HAS_SG_CHAIN
        BUG();
 #endif
+
+       /*
+        * offset and length are unused for chain entry.  Clear them.
+        */
+       prv[prv_nents - 1].offset = 0;
+       prv[prv_nents - 1].length = 0;
+
        /*
         * Set lowest bit to indicate a link pointer, and make sure to clear
         * the termination bit if it happens to be set.
@@ -188,43 +203,23 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
 
 /**
  * sg_mark_end - Mark the end of the scatterlist
- * @sgl:       Scatterlist
- * @nents:     Number of entries in sgl
+ * @sg:                 SG entryScatterlist
  *
  * Description:
- *   Marks the last entry as the termination point for sg_next()
+ *   Marks the passed in sg entry as the termination point for the sg
+ *   table. A call to sg_next() on this entry will return NULL.
  *
  **/
-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)
+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;
+       BUG_ON(sg->sg_magic != SG_MAGIC);
 #endif
-       sg_mark_end(sg, 1);
-       sg_set_buf(sg, buf, buflen);
+       /*
+        * Set termination bit, clear potential chain bit
+        */
+       sg->page_link |= 0x02;
+       sg->page_link &= ~0x01;
 }
 
 /**
@@ -240,7 +235,6 @@ static inline void sg_init_one(struct scatterlist *sg, const void *buf,
 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
        {
                unsigned int i;
@@ -248,6 +242,25 @@ static inline void sg_init_table(struct scatterlist *sgl, unsigned int nents)
                        sgl[i].sg_magic = SG_MAGIC;
        }
 #endif
+       sg_mark_end(&sgl[nents - 1]);
+}
+
+/**
+ * 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)
+{
+       sg_init_table(sg, 1);
+       sg_set_buf(sg, buf, buflen);
 }
 
 /**