Commit 50169d07 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring/rsrc: separate kbuf offset adjustments 



Kernel registered buffers are special because segments are not uniform
in size, and we have a bunch of optimisations based on that uniformity
for normal buffers. Handle kbuf separately, it'll be cleaner this way.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4e9e5990b0ab5aee723c0be5cd9b5bcf810375f9.1744882081.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 1ac57128

io_uring/rsrc.c

+7 −12
Original line number Diff line number Diff line
@@ -1048,11 +1048,14 @@ static int io_import_fixed(int ddir, struct iov_iter *iter, 
	if (!(imu->dir & (1 << ddir)))

		return -EFAULT;



	/*

	 * Might not be a start of buffer, set size appropriately

	 * and advance us to the beginning.

	 */

	offset = buf_addr - imu->ubuf;



	if (imu->is_kbuf) {

		iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);

		iov_iter_advance(iter, offset);

		return 0;

	}



	iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);



	/*
@@ -1072,17 +1075,9 @@ static int io_import_fixed(int ddir, struct iov_iter *iter, 
	 * be folio_size aligned.

	 */

	bvec = imu->bvec;



	/*

	 * Kernel buffer bvecs, on the other hand, don't necessarily

	 * have the size property of user registered ones, so we have

	 * to use the slow iter advance.

	 */

	if (offset < bvec->bv_len) {

		iter->count -= offset;

		iter->iov_offset = offset;

	} else if (imu->is_kbuf) {

		iov_iter_advance(iter, offset);

	} else {

		unsigned long seg_skip;