From 585079b6e425387b5f8ec242fc38081c31ca41ee Mon Sep 17 00:00:00 2001 From: Kanchan Joshi Date: Tue, 23 Aug 2022 21:44:43 +0530 Subject: [PATCH] nvme: wire up async polling for io passthrough commands 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 Signed-off-by: Anuj Gupta Link: https://lore.kernel.org/r/20220823161443.49436-5-joshi.k@samsung.com Signed-off-by: Jens Axboe --- 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 66446f1e06cf..0038283702a1 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 1bdf714dcd9e..fdcbc93dea21 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,