Merge git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

[linux-2.6-block.git] / include / linux / scatterlist.h

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 22b2131bcdcd23339ef068b22cb8cbf8e6a55ea5..51f52020ad5fdd44ab4fdfa6ad2e0063c4780947 100644 (file)
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -65,16 +65,18 @@ struct sg_table {
  */
 
 #define SG_MAGIC       0x87654321
+#define SG_CHAIN       0x01UL
+#define SG_END         0x02UL
 
 /*
  * 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_is_chain(sg)                ((sg)->page_link & SG_CHAIN)
+#define sg_is_last(sg)         ((sg)->page_link & SG_END)
 #define sg_chain_ptr(sg)       \
-       ((struct scatterlist *) ((sg)->page_link & ~0x03))
+       ((struct scatterlist *) ((sg)->page_link & ~(SG_CHAIN | SG_END)))
 
 /**
  * sg_assign_page - Assign a given page to an SG entry
@@ -88,13 +90,13 @@ struct sg_table {
  **/
 static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
 {
-       unsigned long page_link = sg->page_link & 0x3;
+       unsigned long page_link = sg->page_link & (SG_CHAIN | SG_END);
 
        /*
         * 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);
+       BUG_ON((unsigned long) page & (SG_CHAIN | SG_END));
 #ifdef CONFIG_DEBUG_SG
        BUG_ON(sg->sg_magic != SG_MAGIC);
        BUG_ON(sg_is_chain(sg));
@@ -130,7 +132,7 @@ static inline struct page *sg_page(struct scatterlist *sg)
        BUG_ON(sg->sg_magic != SG_MAGIC);
        BUG_ON(sg_is_chain(sg));
 #endif
-       return (struct page *)((sg)->page_link & ~0x3);
+       return (struct page *)((sg)->page_link & ~(SG_CHAIN | SG_END));
 }
 
 /**
@@ -178,7 +180,8 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
         * Set lowest bit to indicate a link pointer, and make sure to clear
         * the termination bit if it happens to be set.
         */
-       prv[prv_nents - 1].page_link = ((unsigned long) sgl | 0x01) & ~0x02;
+       prv[prv_nents - 1].page_link = ((unsigned long) sgl | SG_CHAIN)
+                                       & ~SG_END;
 }
 
 /**
@@ -198,8 +201,8 @@ static inline void sg_mark_end(struct scatterlist *sg)
        /*
         * Set termination bit, clear potential chain bit
         */
-       sg->page_link |= 0x02;
-       sg->page_link &= ~0x01;
+       sg->page_link |= SG_END;
+       sg->page_link &= ~SG_CHAIN;
 }
 
 /**
@@ -215,7 +218,7 @@ static inline void sg_unmark_end(struct scatterlist *sg)
 #ifdef CONFIG_DEBUG_SG
        BUG_ON(sg->sg_magic != SG_MAGIC);
 #endif
-       sg->page_link &= ~0x02;
+       sg->page_link &= ~SG_END;
 }
 
 /**
@@ -248,6 +251,24 @@ static inline void *sg_virt(struct scatterlist *sg)
        return page_address(sg_page(sg)) + sg->offset;
 }
 
+/**
+ * sg_init_marker - Initialize markers in sg table
+ * @sgl:          The SG table
+ * @nents:        Number of entries in table
+ *
+ **/
+static inline void sg_init_marker(struct scatterlist *sgl,
+                                 unsigned int nents)
+{
+#ifdef CONFIG_DEBUG_SG
+       unsigned int i;
+
+       for (i = 0; i < nents; i++)
+               sgl[i].sg_magic = SG_MAGIC;
+#endif
+       sg_mark_end(&sgl[nents - 1]);
+}
+
 int sg_nents(struct scatterlist *sg);
 int sg_nents_for_len(struct scatterlist *sg, u64 len);
 struct scatterlist *sg_next(struct scatterlist *);