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iov_iter: optimise bvec iov_iter_advance()

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iov_iter_advance() is heavily used, but implemented through generic
means. For bvecs there is a specifically crafted function for that, so
use bvec_iter_advance() instead, it's faster and slimmer.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-01-09 16:03:01 +00:00 committed by Jens Axboe
parent ecd7fba0ad
commit 54c8195b4e
1 changed files with 19 additions and 0 deletions
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19
lib/iov_iter.c
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@ -1065,6 +1065,21 @@ static void pipe_advance(struct iov_iter *i, size_t size)
pipe_truncate(i);
}
static void iov_iter_bvec_advance(struct iov_iter *i, size_t size)
{
struct bvec_iter bi;
bi.bi_size = i->count;
bi.bi_bvec_done = i->iov_offset;
bi.bi_idx = 0;
bvec_iter_advance(i->bvec, &bi, size);
i->bvec += bi.bi_idx;
i->nr_segs -= bi.bi_idx;
i->count = bi.bi_size;
i->iov_offset = bi.bi_bvec_done;
}
void iov_iter_advance(struct iov_iter *i, size_t size)
{
if (unlikely(iov_iter_is_pipe(i))) {
@ -1075,6 +1090,10 @@ void iov_iter_advance(struct iov_iter *i, size_t size)
i->count -= size;
return;
}
if (iov_iter_is_bvec(i)) {
iov_iter_bvec_advance(i, size);
return;
}
iterate_and_advance(i, size, v, 0, 0, 0)
}
EXPORT_SYMBOL(iov_iter_advance);