| Message ID | 20210715033704.692967-92-willy@infradead.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Memory folios | expand |
On Thu, Jul 15, 2021 at 04:36:17AM +0100, Matthew Wilcox (Oracle) wrote: > Allow callers to iterate over each folio instead of each page. The > bio need not have been constructed using folios originally. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > --- > include/linux/bio.h | 43 ++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 42 insertions(+), 1 deletion(-) > > diff --git a/include/linux/bio.h b/include/linux/bio.h > index ade93e2de6a1..d462bbc95c4b 100644 > --- a/include/linux/bio.h > +++ b/include/linux/bio.h > @@ -189,7 +189,7 @@ static inline void bio_advance_iter_single(const struct bio *bio, > */ > #define bio_for_each_bvec_all(bvl, bio, i) \ > for (i = 0, bvl = bio_first_bvec_all(bio); \ > - i < (bio)->bi_vcnt; i++, bvl++) \ > + i < (bio)->bi_vcnt; i++, bvl++) > > #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len) > > @@ -314,6 +314,47 @@ static inline struct bio_vec *bio_last_bvec_all(struct bio *bio) > return &bio->bi_io_vec[bio->bi_vcnt - 1]; > } > > +struct folio_iter { > + struct folio *folio; > + size_t offset; > + size_t length; Hm... so after every bio_{first,next}_folio call, we can access the folio, the offset, and the length (both in units of bytes) within the folio? > + size_t _seg_count; > + int _i; And these are private variables that the iteration code should not scribble over? > +}; > + > +static inline > +void bio_first_folio(struct folio_iter *fi, struct bio *bio, int i) > +{ > + struct bio_vec *bvec = bio_first_bvec_all(bio) + i; > + > + fi->folio = page_folio(bvec->bv_page); > + fi->offset = bvec->bv_offset + > + PAGE_SIZE * (bvec->bv_page - &fi->folio->page); > + fi->_seg_count = bvec->bv_len; > + fi->length = min(folio_size(fi->folio) - fi->offset, fi->_seg_count); > + fi->_i = i; > +} > + > +static inline void bio_next_folio(struct folio_iter *fi, struct bio *bio) > +{ > + fi->_seg_count -= fi->length; > + if (fi->_seg_count) { > + fi->folio = folio_next(fi->folio); > + fi->offset = 0; > + fi->length = min(folio_size(fi->folio), fi->_seg_count); > + } else if (fi->_i + 1 < bio->bi_vcnt) { > + bio_first_folio(fi, bio, fi->_i + 1); > + } else { > + fi->folio = NULL; > + } > +} > + > +/* > + * Iterate over each folio in a bio. > + */ > +#define bio_for_each_folio_all(fi, bio) \ > + for (bio_first_folio(&fi, bio, 0); fi.folio; bio_next_folio(&fi, bio)) ...so I guess a sample iteration loop would be something like: struct bio *bio = <get one from somewhere>; struct folio_iter fi; bio_for_each_folio_all(fi, bio) { if (folio_test_dirty(fi.folio)) printk("folio idx 0x%lx is dirty, i hates dirty data!", folio_index(fi.folio)); panic(); } I'll go look through the rest of the patches, but this so far looks pretty straightforward to me. --D > + > enum bip_flags { > BIP_BLOCK_INTEGRITY = 1 << 0, /* block layer owns integrity data */ > BIP_MAPPED_INTEGRITY = 1 << 1, /* ref tag has been remapped */ > -- > 2.30.2 >
On Thu, Jul 15, 2021 at 02:12:54PM -0700, Darrick J. Wong wrote: > On Thu, Jul 15, 2021 at 04:36:17AM +0100, Matthew Wilcox (Oracle) wrote: > > +struct folio_iter { > > + struct folio *folio; > > + size_t offset; > > + size_t length; > > Hm... so after every bio_{first,next}_folio call, we can access the > folio, the offset, and the length (both in units of bytes) within the > folio? Correct. > > + size_t _seg_count; > > + int _i; > > And these are private variables that the iteration code should not > scribble over? Indeed! > > +/* > > + * Iterate over each folio in a bio. > > + */ > > +#define bio_for_each_folio_all(fi, bio) \ > > + for (bio_first_folio(&fi, bio, 0); fi.folio; bio_next_folio(&fi, bio)) > > ...so I guess a sample iteration loop would be something like: > > struct bio *bio = <get one from somewhere>; > struct folio_iter fi; > > bio_for_each_folio_all(fi, bio) { > if (folio_test_dirty(fi.folio)) > printk("folio idx 0x%lx is dirty, i hates dirty data!", > folio_index(fi.folio)); > panic(); > } > > I'll go look through the rest of the patches, but this so far looks > pretty straightforward to me. Something very much like that! +static void iomap_read_end_io(struct bio *bio) { + struct folio_iter fi; + bio_for_each_folio_all(fi, bio) + iomap_finish_folio_read(fi.folio, fi.offset, fi.length, error);
diff --git a/include/linux/bio.h b/include/linux/bio.h index ade93e2de6a1..d462bbc95c4b 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -189,7 +189,7 @@ static inline void bio_advance_iter_single(const struct bio *bio, */ #define bio_for_each_bvec_all(bvl, bio, i) \ for (i = 0, bvl = bio_first_bvec_all(bio); \ - i < (bio)->bi_vcnt; i++, bvl++) \ + i < (bio)->bi_vcnt; i++, bvl++) #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len) @@ -314,6 +314,47 @@ static inline struct bio_vec *bio_last_bvec_all(struct bio *bio) return &bio->bi_io_vec[bio->bi_vcnt - 1]; } +struct folio_iter { + struct folio *folio; + size_t offset; + size_t length; + size_t _seg_count; + int _i; +}; + +static inline +void bio_first_folio(struct folio_iter *fi, struct bio *bio, int i) +{ + struct bio_vec *bvec = bio_first_bvec_all(bio) + i; + + fi->folio = page_folio(bvec->bv_page); + fi->offset = bvec->bv_offset + + PAGE_SIZE * (bvec->bv_page - &fi->folio->page); + fi->_seg_count = bvec->bv_len; + fi->length = min(folio_size(fi->folio) - fi->offset, fi->_seg_count); + fi->_i = i; +} + +static inline void bio_next_folio(struct folio_iter *fi, struct bio *bio) +{ + fi->_seg_count -= fi->length; + if (fi->_seg_count) { + fi->folio = folio_next(fi->folio); + fi->offset = 0; + fi->length = min(folio_size(fi->folio), fi->_seg_count); + } else if (fi->_i + 1 < bio->bi_vcnt) { + bio_first_folio(fi, bio, fi->_i + 1); + } else { + fi->folio = NULL; + } +} + +/* + * Iterate over each folio in a bio. + */ +#define bio_for_each_folio_all(fi, bio) \ + for (bio_first_folio(&fi, bio, 0); fi.folio; bio_next_folio(&fi, bio)) + enum bip_flags { BIP_BLOCK_INTEGRITY = 1 << 0, /* block layer owns integrity data */ BIP_MAPPED_INTEGRITY = 1 << 1, /* ref tag has been remapped */
Allow callers to iterate over each folio instead of each page. The bio need not have been constructed using folios originally. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- include/linux/bio.h | 43 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 42 insertions(+), 1 deletion(-)