aio: use iovec array rather than the single one (00fefb9c) · Commits · 戴 / test

Previously, we only offer a single iovec to handle all the read/write cases, so the PREADV/PWRITEV request always need to alloc more iovec buffer when copying user vectors. If we use a tmp iovec array rather than the single one, some small PREADV/PWRITEV workloads(vector size small than the tmp buffer) will not need to alloc more iovec buffer when copying user vectors. Reviewed-by:

Jeff Moyer <jmoyer@redhat.com> Signed-off-by:

Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by:

Benjamin LaHaise <bcrl@kvack.org>

fs/aio.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -1243,12 +1243,12 @@ static ssize_t aio_setup_vectored_rw(struct kiocb *kiocb,
		if (compat)
		ret = compat_rw_copy_check_uvector(rw,
		(struct compat_iovec __user *)buf,
		nr_segs, 1, iovec, iovec);
		nr_segs, UIO_FASTIOV, iovec, iovec);
		else
		#endif
		ret = rw_copy_check_uvector(rw,
		(struct iovec __user *)buf,
		nr_segs, 1, iovec, iovec);
		nr_segs, UIO_FASTIOV, iovec, iovec);
		if (ret < 0)
		return ret;

		@@ -1285,7 +1285,7 @@ static ssize_t aio_run_iocb(struct kiocb *req, unsigned opcode,
		fmode_t mode;
		aio_rw_op *rw_op;
		rw_iter_op *iter_op;
		struct iovec inline_vec, *iovec = &inline_vec;
		struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
		struct iov_iter iter;

		switch (opcode) {
		@@ -1320,7 +1320,7 @@ rw_common:
		if (!ret)
		ret = rw_verify_area(rw, file, &req->ki_pos, req->ki_nbytes);
		if (ret < 0) {
		if (iovec != &inline_vec)
		if (iovec != inline_vecs)
		kfree(iovec);
		return ret;
		}
		@@ -1367,7 +1367,7 @@ rw_common:
		return -EINVAL;
		}

		if (iovec != &inline_vec)
		if (iovec != inline_vecs)
		kfree(iovec);

		if (ret != -EIOCBQUEUED) {

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