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io_uring: remove nr_segs recalculation in io_import_kbuf()

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io_import_kbuf() recalculates iter->nr_segs to reflect only the bvecs
needed for the requested byte range. This was added to provide an
accurate segment count to bio_iov_bvec_set(), which copied nr_segs to
bio->bi_vcnt for use as a bio split hint.

The previous two patches eliminated this dependency:
 - bio_may_need_split() now uses bi_iter instead of bi_vcnt for split
   decisions
 - bio_iov_bvec_set() no longer copies nr_segs to bi_vcnt

Since nr_segs is no longer used for bio split decisions, the
recalculation loop is unnecessary. The iov_iter already has the correct
bi_size to cap iteration, so an oversized nr_segs is harmless.

Link: https://lkml.org/lkml/2025/4/16/351
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei
2025-12-31 11:00:57 +08:00
committed by Jens Axboe
parent 6418643148
commit 15f506a77a
1 changed files with 0 additions and 11 deletions
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11
io_uring/rsrc.c
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@@ -1055,17 +1055,6 @@ static int io_import_kbuf(int ddir, struct iov_iter *iter,
iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, count);
iov_iter_advance(iter, offset);
if (count < imu->len) {
const struct bio_vec *bvec = iter->bvec;
len += iter->iov_offset;
while (len > bvec->bv_len) {
len -= bvec->bv_len;
bvec++;
}
iter->nr_segs = 1 + bvec - iter->bvec;
}
return 0;
}