Commit f857acfc authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Christoph Hellwig
Browse files

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: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 28e4576d

include/linux/scatterlist.h

+23 −6
Original line number Diff line number Diff line
@@ -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);

}



/**