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lib/scatterlist: cleanup macros into static inline functions

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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>
This commit is contained in:
Logan Gunthorpe 2021-11-17 14:53:48 -07:00 committed by Christoph Hellwig
parent 28e4576d55
commit f857acfc45
1 changed files with 23 additions and 6 deletions
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29
include/linux/scatterlist.h
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@ -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);
}
/**