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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2023-06-21 19:45:47 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-06-24 02:59:28 +0300 |
| commit | bdadc6d83156016d2b5eed582c1458c881c53a1e (patch) | |
| tree | 621d00a1f75e5423f071ee14ae0609cddafe9737 | |
| parent | 982a7194afc9a58ec55ed174c61869c2722bb918 (diff) | |
| download | linux-bdadc6d83156016d2b5eed582c1458c881c53a1e.tar.xz | |
scatterlist: add sg_set_folio()
This wrapper for sg_set_page() lets drivers add folios to a scatterlist
more easily. We could, perhaps, do better by using a different page in
the folio if offset is larger than UINT_MAX, but let's hope we get a
better data structure than this before we need to care about such large
folios.
Link: https://lkml.kernel.org/r/20230621164557.3510324-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | include/linux/scatterlist.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index ec46d8e8e49d..77df3d7b18a6 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -141,6 +141,30 @@ static inline void sg_set_page(struct scatterlist *sg, struct page *page, sg->length = len; } +/** + * sg_set_folio - Set sg entry to point at given folio + * @sg: SG entry + * @folio: The folio + * @len: Length of data + * @offset: Offset into folio + * + * Description: + * Use this function to set an sg entry pointing at a folio, never assign + * the folio directly. We encode sg table information in the lower bits + * of the folio pointer. See sg_page() for looking up the page belonging + * to an sg entry. + * + **/ +static inline void sg_set_folio(struct scatterlist *sg, struct folio *folio, + size_t len, size_t offset) +{ + WARN_ON_ONCE(len > UINT_MAX); + WARN_ON_ONCE(offset > UINT_MAX); + sg_assign_page(sg, &folio->page); + sg->offset = offset; + sg->length = len; +} + static inline struct page *sg_page(struct scatterlist *sg) { #ifdef CONFIG_DEBUG_SG |