lib/scatterlist: cleanup macros into static inline functions

Convert the sg_is_chain(), sg_is_last() and sg_chain_ptr() macros
into static inline functions. There's no reason for these to be macros
and static inline are generally preferred these days.

Also introduce the SG_PAGE_LINK_MASK define so the P2PDMA work, which is
adding another bit to this mask, can do so more easily.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 266754a55327ea05dcda9cb5365270ddc9e0bf29..7ff9d6386c1220d7969c0b5a9c524739c49881af 100644 (file)
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -69,10 +69,27 @@ struct sg_append_table {
  * 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 & SG_CHAIN)
-#define sg_is_last(sg)         ((sg)->page_link & SG_END)
-#define sg_chain_ptr(sg)       \
-       ((struct scatterlist *) ((sg)->page_link & ~(SG_CHAIN | SG_END)))
+#define SG_PAGE_LINK_MASK (SG_CHAIN | SG_END)
+
+static inline unsigned int __sg_flags(struct scatterlist *sg)
+{
+       return sg->page_link & SG_PAGE_LINK_MASK;
+}
+
+static inline struct scatterlist *sg_chain_ptr(struct scatterlist *sg)
+{
+       return (struct scatterlist *)(sg->page_link & ~SG_PAGE_LINK_MASK);
+}
+
+static inline bool sg_is_chain(struct scatterlist *sg)
+{
+       return __sg_flags(sg) & SG_CHAIN;
+}
+
+static inline bool sg_is_last(struct scatterlist *sg)
+{
+       return __sg_flags(sg) & SG_END;
+}
 
 /**
  * sg_assign_page - Assign a given page to an SG entry
@@ -92,7 +109,7 @@ static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
         * 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 & (SG_CHAIN | SG_END));
+       BUG_ON((unsigned long)page & SG_PAGE_LINK_MASK);
 #ifdef CONFIG_DEBUG_SG
        BUG_ON(sg_is_chain(sg));
 #endif
@@ -126,7 +143,7 @@ static inline struct page *sg_page(struct scatterlist *sg)
 #ifdef CONFIG_DEBUG_SG
        BUG_ON(sg_is_chain(sg));
 #endif
-       return (struct page *)((sg)->page_link & ~(SG_CHAIN | SG_END));
+       return (struct page *)((sg)->page_link & ~SG_PAGE_LINK_MASK);
 }
 
 /**