[PATCH for-next v2 4/4] nvme: wire up async polling for io passthrough commands
Kanchan Joshi
joshi.k at samsung.com
Sun Aug 7 11:36:07 PDT 2022
Store a cookie during submission, and use that to implement
completion-polling inside the ->uring_cmd_iopoll handler.
This handler makes use of existing bio poll facility.
Signed-off-by: Kanchan Joshi <joshi.k at samsung.com>
Signed-off-by: Anuj Gupta <anuj20.g at samsung.com>
---
drivers/nvme/host/core.c | 1 +
drivers/nvme/host/ioctl.c | 73 ++++++++++++++++++++++++++++++++---
drivers/nvme/host/multipath.c | 1 +
drivers/nvme/host/nvme.h | 2 +
4 files changed, 72 insertions(+), 5 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 2429b11eb9a8..77b6c2882afd 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3976,6 +3976,7 @@ static const struct file_operations nvme_ns_chr_fops = {
.unlocked_ioctl = nvme_ns_chr_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.uring_cmd = nvme_ns_chr_uring_cmd,
+ .uring_cmd_iopoll = nvme_ns_chr_uring_cmd_iopoll,
};
static int nvme_add_ns_cdev(struct nvme_ns *ns)
diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 27614bee7380..7756b439a688 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -391,11 +391,19 @@ static void nvme_uring_cmd_end_io(struct request *req, blk_status_t err)
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;
- /* this takes care of moving rest of completion-work to task context */
- io_uring_cmd_complete_in_task(ioucmd, nvme_uring_task_cb);
+
+ /*
+ * For iopoll, complete it directly.
+ * Otherwise, move the completion to task work.
+ */
+ if (cookie != NULL && blk_rq_is_poll(req))
+ nvme_uring_task_cb(ioucmd);
+ else
+ io_uring_cmd_complete_in_task(ioucmd, nvme_uring_task_cb);
}
static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
@@ -445,7 +453,10 @@ static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
rq_flags = REQ_NOWAIT;
blk_flags = BLK_MQ_REQ_NOWAIT;
}
+ if (issue_flags & IO_URING_F_IOPOLL)
+ rq_flags |= REQ_POLLED;
+retry:
req = nvme_alloc_user_request(q, &c, nvme_to_user_ptr(d.addr),
d.data_len, nvme_to_user_ptr(d.metadata),
d.metadata_len, 0, &meta, d.timeout_ms ?
@@ -456,6 +467,17 @@ static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
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)) {
+ /* we can't poll this, so alloc regular req instead */
+ blk_mq_free_request(req);
+ rq_flags &= ~REQ_POLLED;
+ goto retry;
+ } else {
+ WRITE_ONCE(ioucmd->cookie, req->bio);
+ req->bio->bi_opf |= REQ_POLLED;
+ }
+ }
/* to free bio on completion, as req->bio will be null at that time */
pdu->bio = req->bio;
pdu->meta = meta;
@@ -559,9 +581,6 @@ long nvme_ns_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
static int nvme_uring_cmd_checks(unsigned int issue_flags)
{
- /* IOPOLL not supported yet */
- if (issue_flags & IO_URING_F_IOPOLL)
- return -EOPNOTSUPP;
/* NVMe passthrough requires big SQE/CQE support */
if ((issue_flags & (IO_URING_F_SQE128|IO_URING_F_CQE32)) !=
@@ -604,6 +623,23 @@ int nvme_ns_chr_uring_cmd(struct io_uring_cmd *ioucmd, unsigned int issue_flags)
return nvme_ns_uring_cmd(ns, ioucmd, issue_flags);
}
+int nvme_ns_chr_uring_cmd_iopoll(struct io_uring_cmd *ioucmd)
+{
+ struct bio *bio;
+ int ret = 0;
+ struct nvme_ns *ns;
+ struct request_queue *q;
+
+ rcu_read_lock();
+ bio = READ_ONCE(ioucmd->cookie);
+ ns = container_of(file_inode(ioucmd->file)->i_cdev,
+ struct nvme_ns, cdev);
+ q = ns->queue;
+ if (test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && bio && bio->bi_bdev)
+ ret = bio_poll(bio, NULL, 0);
+ rcu_read_unlock();
+ return ret;
+}
#ifdef CONFIG_NVME_MULTIPATH
static int nvme_ns_head_ctrl_ioctl(struct nvme_ns *ns, unsigned int cmd,
void __user *argp, struct nvme_ns_head *head, int srcu_idx)
@@ -685,6 +721,29 @@ int nvme_ns_head_chr_uring_cmd(struct io_uring_cmd *ioucmd,
srcu_read_unlock(&head->srcu, srcu_idx);
return ret;
}
+
+int nvme_ns_head_chr_uring_cmd_iopoll(struct io_uring_cmd *ioucmd)
+{
+ struct cdev *cdev = file_inode(ioucmd->file)->i_cdev;
+ struct nvme_ns_head *head = container_of(cdev, struct nvme_ns_head, cdev);
+ int srcu_idx = srcu_read_lock(&head->srcu);
+ struct nvme_ns *ns = nvme_find_path(head);
+ struct bio *bio;
+ int ret = 0;
+ struct request_queue *q;
+
+ if (ns) {
+ rcu_read_lock();
+ bio = READ_ONCE(ioucmd->cookie);
+ q = ns->queue;
+ if (test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && bio
+ && bio->bi_bdev)
+ ret = bio_poll(bio, NULL, 0);
+ rcu_read_unlock();
+ }
+ srcu_read_unlock(&head->srcu, srcu_idx);
+ return ret;
+}
#endif /* CONFIG_NVME_MULTIPATH */
int nvme_dev_uring_cmd(struct io_uring_cmd *ioucmd, unsigned int issue_flags)
@@ -692,6 +751,10 @@ int nvme_dev_uring_cmd(struct io_uring_cmd *ioucmd, unsigned int issue_flags)
struct nvme_ctrl *ctrl = ioucmd->file->private_data;
int ret;
+ /* IOPOLL not supported yet */
+ if (issue_flags & IO_URING_F_IOPOLL)
+ return -EOPNOTSUPP;
+
ret = nvme_uring_cmd_checks(issue_flags);
if (ret)
return ret;
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 6ef497c75a16..00f2f81e20fa 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -439,6 +439,7 @@ static const struct file_operations nvme_ns_head_chr_fops = {
.unlocked_ioctl = nvme_ns_head_chr_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.uring_cmd = nvme_ns_head_chr_uring_cmd,
+ .uring_cmd_iopoll = nvme_ns_head_chr_uring_cmd_iopoll,
};
static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index bdc0ff7ed9ab..3f2d3dda6e6c 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -821,6 +821,8 @@ long nvme_ns_head_chr_ioctl(struct file *file, unsigned int cmd,
unsigned long arg);
long nvme_dev_ioctl(struct file *file, unsigned int cmd,
unsigned long arg);
+int nvme_ns_chr_uring_cmd_iopoll(struct io_uring_cmd *ioucmd);
+int nvme_ns_head_chr_uring_cmd_iopoll(struct io_uring_cmd *ioucmd);
int nvme_ns_chr_uring_cmd(struct io_uring_cmd *ioucmd,
unsigned int issue_flags);
int nvme_ns_head_chr_uring_cmd(struct io_uring_cmd *ioucmd,
--
2.25.1
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