[PATCH for-next v3 4/4] nvme: wire up fixed buffer support for nvme passthrough

Kanchan Joshi
2022-09-02T15:29:01Z

if io_uring sends passthrough command with IO_URING_F_FIXEDBUFS flag,
use the pre-registered buffer to form the bio.
While at it modify nvme_submit_user_cmd to take ubuffer as plain integer
argument, and do away with nvme_to_user_ptr conversion in callers.

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
---
drivers/nvme/host/ioctl.c | 38 ++++++++++++++++++++++++++------------
1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 7756b439a688..5a4649293e86 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -65,10 +65,11 @@ static int nvme_finish_user_metadata(struct request *req, void __user *ubuf,
}

static struct request *nvme_alloc_user_request(struct request_queue *q,
- struct nvme_command *cmd, void __user *ubuffer,
+ struct nvme_command *cmd, u64 ubuffer,
unsigned bufflen, void __user *meta_buffer, unsigned meta_len,
u32 meta_seed, void **metap, unsigned timeout, bool vec,
- blk_opf_t rq_flags, blk_mq_req_flags_t blk_flags)
+ blk_opf_t rq_flags, blk_mq_req_flags_t blk_flags,
+ struct io_uring_cmd *ioucmd, bool fixedbufs)
{
bool write = nvme_is_write(cmd);
struct nvme_ns *ns = q->queuedata;
@@ -89,14 +90,27 @@ static struct request *nvme_alloc_user_request(struct request_queue *q,

if (ubuffer && bufflen) {
if (!vec)
- ret = blk_rq_map_user(q, req, NULL, ubuffer, bufflen,
- GFP_KERNEL);
+ if (fixedbufs) {
+ struct iov_iter iter;
+
+ ret = io_uring_cmd_import_fixed(ubuffer,
+ bufflen, rq_data_dir(req),
+ &iter, ioucmd);
+ if (ret < 0)
+ goto out;
+ ret = blk_rq_map_user_bvec(req, &iter);
+ } else {
+ ret = blk_rq_map_user(q, req, NULL,
+ nvme_to_user_ptr(ubuffer),
+ bufflen, GFP_KERNEL);
+ }
else {
struct iovec fast_iov[UIO_FASTIOV];
struct iovec *iov = fast_iov;
struct iov_iter iter;

- ret = import_iovec(rq_data_dir(req), ubuffer, bufflen,
+ ret = import_iovec(rq_data_dir(req),
+ nvme_to_user_ptr(ubuffer), bufflen,
UIO_FASTIOV, &iov, &iter);
if (ret < 0)
goto out;
@@ -132,7 +146,7 @@ static struct request *nvme_alloc_user_request(struct request_queue *q,
}

static int nvme_submit_user_cmd(struct request_queue *q,
- struct nvme_command *cmd, void __user *ubuffer,
+ struct nvme_command *cmd, u64 ubuffer,
unsigned bufflen, void __user *meta_buffer, unsigned meta_len,
u32 meta_seed, u64 *result, unsigned timeout, bool vec)
{
@@ -142,7 +156,7 @@ static int nvme_submit_user_cmd(struct request_queue *q,
int ret;

req = nvme_alloc_user_request(q, cmd, ubuffer, bufflen, meta_buffer,
- meta_len, meta_seed, &meta, timeout, vec, 0, 0);
+ meta_len, meta_seed, &meta, timeout, vec, 0, 0, NULL, 0);
if (IS_ERR(req))
return PTR_ERR(req);

@@ -220,7 +234,7 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
c.rw.appmask = cpu_to_le16(io.appmask);

return nvme_submit_user_cmd(ns->queue, &c,
- nvme_to_user_ptr(io.addr), length,
+ io.addr, length,
metadata, meta_len, lower_32_bits(io.slba), NULL, 0,
false);
}
@@ -274,7 +288,7 @@ static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
timeout = msecs_to_jiffies(cmd.timeout_ms);

status = nvme_submit_user_cmd(ns ? ns->queue : ctrl->admin_q, &c,
- nvme_to_user_ptr(cmd.addr), cmd.data_len,
+ cmd.addr, cmd.data_len,
nvme_to_user_ptr(cmd.metadata), cmd.metadata_len,
0, &result, timeout, false);

@@ -320,7 +334,7 @@ static int nvme_user_cmd64(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
timeout = msecs_to_jiffies(cmd.timeout_ms);

status = nvme_submit_user_cmd(ns ? ns->queue : ctrl->admin_q, &c,
- nvme_to_user_ptr(cmd.addr), cmd.data_len,
+ cmd.addr, cmd.data_len,
nvme_to_user_ptr(cmd.metadata), cmd.metadata_len,
0, &cmd.result, timeout, vec);

@@ -457,11 +471,11 @@ static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
rq_flags |= REQ_POLLED;

retry:
- req = nvme_alloc_user_request(q, &c, nvme_to_user_ptr(d.addr),
+ req = nvme_alloc_user_request(q, &c, d.addr,
d.data_len, nvme_to_user_ptr(d.metadata),
d.metadata_len, 0, &meta, d.timeout_ms ?
msecs_to_jiffies(d.timeout_ms) : 0, vec, rq_flags,
- blk_flags);
+ blk_flags, ioucmd, issue_flags & IO_URING_F_FIXEDBUFS);
if (IS_ERR(req))
return PTR_ERR(req);
req->end_io = nvme_uring_cmd_end_io;
--
2.25.1