block: Add bio_advance()
This is prep work for immutable bio vecs; we first want to centralize where bvecs are modified. Next two patches convert some existing code to use this function. Signed-off-by: Kent Overstreet <koverstreet@google.com> CC: Jens Axboe <axboe@kernel.dk>
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9f060e2231
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fs/bio.c
41
fs/bio.c
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@ -752,6 +752,47 @@ int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
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}
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EXPORT_SYMBOL(bio_add_page);
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/**
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* bio_advance - increment/complete a bio by some number of bytes
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* @bio: bio to advance
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* @bytes: number of bytes to complete
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*
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* This updates bi_sector, bi_size and bi_idx; if the number of bytes to
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* complete doesn't align with a bvec boundary, then bv_len and bv_offset will
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* be updated on the last bvec as well.
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*
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* @bio will then represent the remaining, uncompleted portion of the io.
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*/
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void bio_advance(struct bio *bio, unsigned bytes)
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{
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if (bio_integrity(bio))
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bio_integrity_advance(bio, bytes);
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bio->bi_sector += bytes >> 9;
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bio->bi_size -= bytes;
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if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
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return;
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while (bytes) {
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if (unlikely(bio->bi_idx >= bio->bi_vcnt)) {
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WARN_ONCE(1, "bio idx %d >= vcnt %d\n",
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bio->bi_idx, bio->bi_vcnt);
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break;
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}
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if (bytes >= bio_iovec(bio)->bv_len) {
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bytes -= bio_iovec(bio)->bv_len;
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bio->bi_idx++;
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} else {
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bio_iovec(bio)->bv_len -= bytes;
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bio_iovec(bio)->bv_offset += bytes;
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bytes = 0;
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}
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}
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}
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EXPORT_SYMBOL(bio_advance);
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struct bio_map_data {
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struct bio_vec *iovecs;
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struct sg_iovec *sgvecs;
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@ -248,6 +248,8 @@ extern void bio_endio(struct bio *, int);
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struct request_queue;
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extern int bio_phys_segments(struct request_queue *, struct bio *);
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extern void bio_advance(struct bio *, unsigned);
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extern void bio_init(struct bio *);
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extern void bio_reset(struct bio *);
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@ -197,6 +197,8 @@ enum rq_flag_bits {
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REQ_SECURE)
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#define REQ_CLONE_MASK REQ_COMMON_MASK
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#define BIO_NO_ADVANCE_ITER_MASK (REQ_DISCARD|REQ_WRITE_SAME)
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/* This mask is used for both bio and request merge checking */
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#define REQ_NOMERGE_FLAGS \
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(REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
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