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Merge LinuxKPI changes from DragonflyBSD:

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- Avoid using PAGE_MASK, because Linux defines it differently.
  Use (PAGE_SIZE - 1) instead.
- Add support for for_each_sg_page() and sg_page_iter_dma_address().

Sponsored by:	Mellanox Technologies
This commit is contained in:
Hans Petter Selasky 2015-10-19 11:09:51 +00:00
parent e6d1c6e382
commit b526833859
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=289567
1 changed files with 68 additions and 1 deletions
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69
sys/ofed/include/linux/scatterlist.h
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@ -3,6 +3,7 @@
* Copyright (c) 2010 iX Systems, Inc.
* Copyright (c) 2010 Panasas, Inc.
* Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
* Copyright (c) 2015 Matthew Dillon <dillon@backplane.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -64,6 +65,12 @@ struct sg_table {
unsigned int orig_nents; /* original size of list */
};
struct sg_page_iter {
struct scatterlist *sg;
unsigned int sg_pgoffset; /* page index */
unsigned int maxents;
};
/*
* Maximum number of entries that will be allocated in one piece, if
* a list larger than this is required then chaining will be utilized.
@ -93,7 +100,7 @@ static inline void
sg_set_buf(struct scatterlist *sg, const void *buf, unsigned int buflen)
{
sg_set_page(sg, virt_to_page(buf), buflen,
((uintptr_t)buf) & ~PAGE_MASK);
((uintptr_t)buf) & (PAGE_SIZE - 1));
}
static inline void
@ -326,6 +333,66 @@ sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)
return ret;
}
/*
* Iterate pages in sg list.
*/
static inline void
_sg_iter_next(struct sg_page_iter *iter)
{
struct scatterlist *sg;
unsigned int pgcount;
sg = iter->sg;
pgcount = (sg->offset + sg->length + PAGE_SIZE - 1) >> PAGE_SHIFT;
++iter->sg_pgoffset;
while (iter->sg_pgoffset >= pgcount) {
iter->sg_pgoffset -= pgcount;
sg = sg_next(sg);
--iter->maxents;
if (sg == NULL || iter->maxents == 0)
break;
pgcount = (sg->offset + sg->length + PAGE_SIZE - 1) >> PAGE_SHIFT;
}
iter->sg = sg;
}
/*
* NOTE: pgoffset is really a page index, not a byte offset.
*/
static inline void
_sg_iter_init(struct scatterlist *sgl, struct sg_page_iter *iter,
unsigned int nents, unsigned long pgoffset)
{
if (nents) {
/*
* Nominal case. Note subtract 1 from starting page index
* for initial _sg_iter_next() call.
*/
iter->sg = sgl;
iter->sg_pgoffset = pgoffset - 1;
iter->maxents = nents;
_sg_iter_next(iter);
} else {
/*
* Degenerate case
*/
iter->sg = NULL;
iter->sg_pgoffset = 0;
iter->maxents = 0;
}
}
static inline dma_addr_t
sg_page_iter_dma_address(struct sg_page_iter *spi)
{
return spi->sg->address + (spi->sg_pgoffset << PAGE_SHIFT);
}
#define for_each_sg_page(sgl, iter, nents, pgoffset) \
for (_sg_iter_init(sgl, iter, nents, pgoffset); \
(iter)->sg; _sg_iter_next(iter))
#define for_each_sg(sglist, sg, sgmax, _itr) \
for (_itr = 0, sg = (sglist); _itr < (sgmax); _itr++, sg = sg_next(sg))