nvme: wire up fixed buffer support for nvme passthrough

if io_uring sends passthrough command with IORING_URING_CMD_FIXED flag,
use the pre-registered buffer for IO (non-vectored variant). Pass the
buffer/length to io_uring and get the bvec iterator for the range. Next,
pass this bvec to block-layer and obtain a bio/request for subsequent
processing.

Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Link: https://lore.kernel.org/r/20220930062749.152261-13-anuj20.g@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Kanchan Joshi 2022-09-30 11:57:49 +05:30 committed by Jens Axboe
parent 4d17448682
commit 23fd22e55b

View File

@ -95,8 +95,22 @@ static int nvme_map_user_request(struct request *req, u64 ubuffer,
void *meta = NULL;
int ret;
ret = blk_rq_map_user_io(req, NULL, nvme_to_user_ptr(ubuffer), bufflen,
GFP_KERNEL, vec, 0, 0, rq_data_dir(req));
if (ioucmd && (ioucmd->flags & IORING_URING_CMD_FIXED)) {
struct iov_iter iter;
/* fixedbufs is only for non-vectored io */
if (WARN_ON_ONCE(vec))
return -EINVAL;
ret = io_uring_cmd_import_fixed(ubuffer, bufflen,
rq_data_dir(req), &iter, ioucmd);
if (ret < 0)
goto out;
ret = blk_rq_map_user_iov(q, req, NULL, &iter, GFP_KERNEL);
} else {
ret = blk_rq_map_user_io(req, NULL, nvme_to_user_ptr(ubuffer),
bufflen, GFP_KERNEL, vec, 0, 0,
rq_data_dir(req));
}
if (ret)
goto out;