[PATCH 4/5] nvme: split out metadata vs non metadata end_io uring_cmd completions

Jens Axboe
2022-09-22T18:31:42Z

By splitting up the metadata and non-metadata end_io handling, we can
remove any request dependencies on the normal non-metadata IO path. This
is in preparation for enabling the normal IO passthrough path to pass
the ownership of the request back to the block layer.

Co-developed-by: Stefan Roesch <shr@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
drivers/nvme/host/ioctl.c | 82 +++++++++++++++++++++++++++++++--------
1 file changed, 66 insertions(+), 16 deletions(-)

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index c80b3ecca5c8..1ccc9dd6d434 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -349,9 +349,18 @@ struct nvme_uring_cmd_pdu {
struct bio *bio;
struct request *req;
};
- void *meta; /* kernel-resident buffer */
- void __user *meta_buffer;
u32 meta_len;
+ union {
+ struct {
+ void *meta; /* kernel-resident buffer */
+ void __user *meta_buffer;
+ };
+ struct {
+ u32 nvme_flags;
+ u32 nvme_status;
+ u64 result;
+ };
+ };
};

static inline struct nvme_uring_cmd_pdu *nvme_uring_cmd_pdu(
@@ -360,11 +369,10 @@ static inline struct nvme_uring_cmd_pdu *nvme_uring_cmd_pdu(
return (struct nvme_uring_cmd_pdu *)&ioucmd->pdu;
}

-static void nvme_uring_task_cb(struct io_uring_cmd *ioucmd)
+static void nvme_uring_task_meta_cb(struct io_uring_cmd *ioucmd)
{
struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd);
struct request *req = pdu->req;
- struct bio *bio = req->bio;
int status;
u64 result;

@@ -375,27 +383,43 @@ static void nvme_uring_task_cb(struct io_uring_cmd *ioucmd)

result = le64_to_cpu(nvme_req(req)->result.u64);

- if (pdu->meta)
+ if (pdu->meta_len)
status = nvme_finish_user_metadata(req, pdu->meta_buffer,
pdu->meta, pdu->meta_len, status);
- if (bio)
- blk_rq_unmap_user(bio);
+ if (req->bio)
+ blk_rq_unmap_user(req->bio);
blk_mq_free_request(req);

io_uring_cmd_done(ioucmd, status, result);
}

+static void nvme_uring_task_cb(struct io_uring_cmd *ioucmd)
+{
+ struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd);
+ int status;
+
+ if (pdu->nvme_flags & NVME_REQ_CANCELLED)
+ status = -EINTR;
+ else
+ status = pdu->nvme_status;
+
+ if (pdu->bio)
+ blk_rq_unmap_user(pdu->bio);
+
+ io_uring_cmd_done(ioucmd, status, pdu->result);
+}
+
static enum rq_end_io_ret nvme_uring_cmd_end_io(struct request *req,
blk_status_t err)
{
struct io_uring_cmd *ioucmd = req->end_io_data;
struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd);
- /* extract bio before reusing the same field for request */
- struct bio *bio = pdu->bio;
void *cookie = READ_ONCE(ioucmd->cookie);

- pdu->req = req;
- req->bio = bio;
+ req->bio = pdu->bio;
+ pdu->nvme_flags = nvme_req(req)->flags;
+ pdu->nvme_status = nvme_req(req)->status;
+ pdu->result = le64_to_cpu(nvme_req(req)->result.u64);

/*
* For iopoll, complete it directly.
@@ -406,6 +430,29 @@ static enum rq_end_io_ret nvme_uring_cmd_end_io(struct request *req,
else
io_uring_cmd_complete_in_task(ioucmd, nvme_uring_task_cb);

+ blk_mq_free_request(req);
+ return RQ_END_IO_NONE;
+}
+
+static enum rq_end_io_ret nvme_uring_cmd_end_io_meta(struct request *req,
+ blk_status_t err)
+{
+ struct io_uring_cmd *ioucmd = req->end_io_data;
+ struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd);
+ void *cookie = READ_ONCE(ioucmd->cookie);
+
+ req->bio = pdu->bio;
+ pdu->req = req;
+
+ /*
+ * For iopoll, complete it directly.
+ * Otherwise, move the completion to task work.
+ */
+ if (cookie != NULL && blk_rq_is_poll(req))
+ nvme_uring_task_meta_cb(ioucmd);
+ else
+ io_uring_cmd_complete_in_task(ioucmd, nvme_uring_task_meta_cb);
+
return RQ_END_IO_NONE;
}

@@ -467,8 +514,6 @@ static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
blk_flags);
if (IS_ERR(req))
return PTR_ERR(req);
- req->end_io = nvme_uring_cmd_end_io;
- req->end_io_data = ioucmd;

if (issue_flags & IO_URING_F_IOPOLL && rq_flags & REQ_POLLED) {
if (unlikely(!req->bio)) {
@@ -483,10 +528,15 @@ static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
}
/* to free bio on completion, as req->bio will be null at that time */
pdu->bio = req->bio;
- pdu->meta = meta;
- pdu->meta_buffer = nvme_to_user_ptr(d.metadata);
pdu->meta_len = d.metadata_len;
-
+ req->end_io_data = ioucmd;
+ if (pdu->meta_len) {
+ pdu->meta = meta;
+ pdu->meta_buffer = nvme_to_user_ptr(d.metadata);
+ req->end_io = nvme_uring_cmd_end_io_meta;
+ } else {
+ req->end_io = nvme_uring_cmd_end_io;
+ }
blk_execute_rq_nowait(req, false);
return -EIOCBQUEUED;
}
--
2.35.1