block: bounce: don't access bio->bi_io_vec in copy_to_high_bio_irq
Firstly this patch introduces BVEC_ITER_ALL_INIT for iterating one bio from start to end. As we need to support multipage bvecs, don't access bio->bi_io_vec in copy_to_high_bio_irq(), and just use the standard iterator for that. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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2 changed files with 20 additions and 5 deletions
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@ -113,24 +113,30 @@ int init_emergency_isa_pool(void)
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static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
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{
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unsigned char *vfrom;
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struct bio_vec tovec, *fromvec = from->bi_io_vec;
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struct bio_vec tovec, fromvec;
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struct bvec_iter iter;
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/*
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* The bio of @from is created by bounce, so we can iterate
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* its bvec from start to end, but the @from->bi_iter can't be
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* trusted because it might be changed by splitting.
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*/
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struct bvec_iter from_iter = BVEC_ITER_ALL_INIT;
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bio_for_each_segment(tovec, to, iter) {
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if (tovec.bv_page != fromvec->bv_page) {
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fromvec = bio_iter_iovec(from, from_iter);
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if (tovec.bv_page != fromvec.bv_page) {
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/*
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* fromvec->bv_offset and fromvec->bv_len might have
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* been modified by the block layer, so use the original
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* copy, bounce_copy_vec already uses tovec->bv_len
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*/
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vfrom = page_address(fromvec->bv_page) +
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vfrom = page_address(fromvec.bv_page) +
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tovec.bv_offset;
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bounce_copy_vec(&tovec, vfrom);
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flush_dcache_page(tovec.bv_page);
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}
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fromvec++;
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bio_advance_iter(from, &from_iter, tovec.bv_len);
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}
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}
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@ -125,4 +125,13 @@ static inline bool bvec_iter_rewind(const struct bio_vec *bv,
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((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
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bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
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/* for iterating one bio from start to end */
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#define BVEC_ITER_ALL_INIT (struct bvec_iter) \
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{ \
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.bi_sector = 0, \
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.bi_size = UINT_MAX, \
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.bi_idx = 0, \
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.bi_bvec_done = 0, \
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}
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#endif /* __LINUX_BVEC_ITER_H */
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