This patch defines names for numeric constants that
used in scatter list for more convenient code reading.
Signed-off-by: Cyrill Gorcunov <[email protected]>
---
I'm not sure if it really needed but who knows ;)
Any comments are welcome.
include/linux/scatterlist.h | 21 ++++++++++++---------
1 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 4571231..fcc05a5 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -25,6 +25,9 @@
*/
#define SG_MAGIC 0x87654321
+#define SG_CHAIN 0x1
+#define SG_LAST 0x2
+#define SG_MASK 0x3
/**
* sg_assign_page - Assign a given page to an SG entry
@@ -38,13 +41,13 @@
**/
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_MASK;
/*
* 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_MASK);
#ifdef CONFIG_DEBUG_SG
BUG_ON(sg->sg_magic != SG_MAGIC);
#endif
@@ -73,7 +76,7 @@ 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))
+#define sg_page(sg) ((struct page *) ((sg)->page_link & ~SG_MASK))
/**
* sg_set_buf - Set sg entry to point at given data
@@ -93,10 +96,10 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
* 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_LAST)
#define sg_chain_ptr(sg) \
- ((struct scatterlist *) ((sg)->page_link & ~0x03))
+ ((struct scatterlist *) ((sg)->page_link & ~SG_MASK))
/**
* sg_next - return the next scatterlist entry in a list
@@ -179,7 +182,7 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
#ifndef ARCH_HAS_SG_CHAIN
BUG();
#endif
- prv[prv_nents - 1].page_link = (unsigned long) sgl | 0x01;
+ prv[prv_nents - 1].page_link = (unsigned long) sgl | SG_CHAIN;
}
/**
@@ -193,12 +196,12 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
**/
static inline void sg_mark_end(struct scatterlist *sgl, unsigned int nents)
{
- sgl[nents - 1].page_link = 0x02;
+ sgl[nents - 1].page_link = SG_LAST;
}
static inline void __sg_mark_end(struct scatterlist *sg)
{
- sg->page_link |= 0x02;
+ sg->page_link |= SG_LAST;
}
/**
-
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