Commit 456cba38 authored by Kanchan Joshi's avatar Kanchan Joshi Committed by Jens Axboe
Browse files

nvme: wire-up uring-cmd support for io-passthru on char-device. 



Introduce handler for fops->uring_cmd(), implementing async passthru
on char device (/dev/ngX). The handler supports newly introduced
operation NVME_URING_CMD_IO. This operates on a new structure
nvme_uring_cmd, which is similar to struct nvme_passthru_cmd64 but
without the embedded 8b result field. This field is not needed since
uring-cmd allows to return additional result via big-CQE.

Signed-off-by: default avatarKanchan Joshi <joshi.k@samsung.com>
Signed-off-by: default avatarAnuj Gupta <anuj20.g@samsung.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220511054750.20432-5-joshi.k@samsung.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent bcad2565

drivers/nvme/host/core.c

+1 −0
Original line number Diff line number Diff line
@@ -3699,6 +3699,7 @@ static const struct file_operations nvme_ns_chr_fops = { 
	.release	= nvme_ns_chr_release,

	.unlocked_ioctl	= nvme_ns_chr_ioctl,

	.compat_ioctl	= compat_ptr_ioctl,

	.uring_cmd	= nvme_ns_chr_uring_cmd,

};



static int nvme_add_ns_cdev(struct nvme_ns *ns)

drivers/nvme/host/ioctl.c

+189 −3
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 */

#include <linux/ptrace.h>	/* for force_successful_syscall_return */

#include <linux/nvme_ioctl.h>

#include <linux/io_uring.h>

#include "nvme.h"



/*
@@ -66,7 +67,8 @@ 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,

		unsigned bufflen, void __user *meta_buffer, unsigned meta_len,

		u32 meta_seed, void **metap, unsigned timeout, bool vec)

		u32 meta_seed, void **metap, unsigned timeout, bool vec,

		unsigned int rq_flags, blk_mq_req_flags_t blk_flags)

{

	bool write = nvme_is_write(cmd);

	struct nvme_ns *ns = q->queuedata;
@@ -76,7 +78,7 @@ static struct request *nvme_alloc_user_request(struct request_queue *q, 
	void *meta = NULL;

	int ret;



	req = blk_mq_alloc_request(q, nvme_req_op(cmd), 0);

	req = blk_mq_alloc_request(q, nvme_req_op(cmd) | rq_flags, blk_flags);

	if (IS_ERR(req))

		return req;

	nvme_init_request(req, cmd);
@@ -140,7 +142,7 @@ 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);

			meta_len, meta_seed, &meta, timeout, vec, 0, 0);

	if (IS_ERR(req))

		return PTR_ERR(req);
@@ -330,6 +332,139 @@ static int nvme_user_cmd64(struct nvme_ctrl *ctrl, struct nvme_ns *ns, 
	return status;

}



struct nvme_uring_data {

	__u64	metadata;

	__u64	addr;

	__u32	data_len;

	__u32	metadata_len;

	__u32	timeout_ms;

};



/*

 * This overlays struct io_uring_cmd pdu.

 * Expect build errors if this grows larger than that.

 */

struct nvme_uring_cmd_pdu {

	union {

		struct bio *bio;

		struct request *req;

	};

	void *meta; /* kernel-resident buffer */

	void __user *meta_buffer;

	u32 meta_len;

};



static inline struct nvme_uring_cmd_pdu *nvme_uring_cmd_pdu(

		struct io_uring_cmd *ioucmd)

{

	return (struct nvme_uring_cmd_pdu *)&ioucmd->pdu;

}



static void nvme_uring_task_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;



	if (nvme_req(req)->flags & NVME_REQ_CANCELLED)

		status = -EINTR;

	else

		status = nvme_req(req)->status;



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



	if (pdu->meta)

		status = nvme_finish_user_metadata(req, pdu->meta_buffer,

					pdu->meta, pdu->meta_len, status);

	if (bio)

		blk_rq_unmap_user(bio);

	blk_mq_free_request(req);



	io_uring_cmd_done(ioucmd, status, result);

}



static void 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;



	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);

}



static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,

		struct io_uring_cmd *ioucmd, unsigned int issue_flags)

{

	struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd);

	const struct nvme_uring_cmd *cmd = ioucmd->cmd;

	struct request_queue *q = ns ? ns->queue : ctrl->admin_q;

	struct nvme_uring_data d;

	struct nvme_command c;

	struct request *req;

	unsigned int rq_flags = 0;

	blk_mq_req_flags_t blk_flags = 0;

	void *meta = NULL;



	if (!capable(CAP_SYS_ADMIN))

		return -EACCES;



	c.common.opcode = READ_ONCE(cmd->opcode);

	c.common.flags = READ_ONCE(cmd->flags);

	if (c.common.flags)

		return -EINVAL;



	c.common.command_id = 0;

	c.common.nsid = cpu_to_le32(cmd->nsid);

	if (!nvme_validate_passthru_nsid(ctrl, ns, le32_to_cpu(c.common.nsid)))

		return -EINVAL;



	c.common.cdw2[0] = cpu_to_le32(READ_ONCE(cmd->cdw2));

	c.common.cdw2[1] = cpu_to_le32(READ_ONCE(cmd->cdw3));

	c.common.metadata = 0;

	c.common.dptr.prp1 = c.common.dptr.prp2 = 0;

	c.common.cdw10 = cpu_to_le32(READ_ONCE(cmd->cdw10));

	c.common.cdw11 = cpu_to_le32(READ_ONCE(cmd->cdw11));

	c.common.cdw12 = cpu_to_le32(READ_ONCE(cmd->cdw12));

	c.common.cdw13 = cpu_to_le32(READ_ONCE(cmd->cdw13));

	c.common.cdw14 = cpu_to_le32(READ_ONCE(cmd->cdw14));

	c.common.cdw15 = cpu_to_le32(READ_ONCE(cmd->cdw15));



	d.metadata = READ_ONCE(cmd->metadata);

	d.addr = READ_ONCE(cmd->addr);

	d.data_len = READ_ONCE(cmd->data_len);

	d.metadata_len = READ_ONCE(cmd->metadata_len);

	d.timeout_ms = READ_ONCE(cmd->timeout_ms);



	if (issue_flags & IO_URING_F_NONBLOCK) {

		rq_flags = REQ_NOWAIT;

		blk_flags = BLK_MQ_REQ_NOWAIT;

	}



	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 ?

			msecs_to_jiffies(d.timeout_ms) : 0, 0, rq_flags,

			blk_flags);

	if (IS_ERR(req))

		return PTR_ERR(req);

	req->end_io_data = ioucmd;



	/* 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;



	blk_execute_rq_nowait(req, 0, nvme_uring_cmd_end_io);

	return -EIOCBQUEUED;

}



static bool is_ctrl_ioctl(unsigned int cmd)

{

	if (cmd == NVME_IOCTL_ADMIN_CMD || cmd == NVME_IOCTL_ADMIN64_CMD)
@@ -421,6 +556,42 @@ long nvme_ns_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
	return __nvme_ioctl(ns, cmd, (void __user *)arg);

}



static int nvme_ns_uring_cmd(struct nvme_ns *ns, struct io_uring_cmd *ioucmd,

			     unsigned int issue_flags)

{

	struct nvme_ctrl *ctrl = ns->ctrl;

	int ret;



	BUILD_BUG_ON(sizeof(struct nvme_uring_cmd_pdu) > sizeof(ioucmd->pdu));



	/* IOPOLL not supported yet */

	if (issue_flags & IO_URING_F_IOPOLL)

		return -EOPNOTSUPP;



	/* NVMe passthrough requires bit SQE/CQE support */

	if ((issue_flags & (IO_URING_F_SQE128|IO_URING_F_CQE32)) !=

	    (IO_URING_F_SQE128|IO_URING_F_CQE32))

		return -EOPNOTSUPP;



	switch (ioucmd->cmd_op) {

	case NVME_URING_CMD_IO:

		ret = nvme_uring_cmd_io(ctrl, ns, ioucmd, issue_flags);

		break;

	default:

		ret = -ENOTTY;

	}



	return ret;

}



int nvme_ns_chr_uring_cmd(struct io_uring_cmd *ioucmd, unsigned int issue_flags)

{

	struct nvme_ns *ns = container_of(file_inode(ioucmd->file)->i_cdev,

			struct nvme_ns, cdev);



	return nvme_ns_uring_cmd(ns, ioucmd, issue_flags);

}



#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)
@@ -487,6 +658,21 @@ long nvme_ns_head_chr_ioctl(struct file *file, unsigned int cmd, 
	srcu_read_unlock(&head->srcu, srcu_idx);

	return ret;

}



int nvme_ns_head_chr_uring_cmd(struct io_uring_cmd *ioucmd,

		unsigned int issue_flags)

{

	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);

	int ret = -EINVAL;



	if (ns)

		ret = nvme_ns_uring_cmd(ns, ioucmd, issue_flags);

	srcu_read_unlock(&head->srcu, srcu_idx);

	return ret;

}

#endif /* CONFIG_NVME_MULTIPATH */



static int nvme_dev_user_cmd(struct nvme_ctrl *ctrl, void __user *argp)

drivers/nvme/host/multipath.c

+1 −0
Original line number Diff line number Diff line
@@ -437,6 +437,7 @@ static const struct file_operations nvme_ns_head_chr_fops = { 
	.release	= nvme_ns_head_chr_release,

	.unlocked_ioctl	= nvme_ns_head_chr_ioctl,

	.compat_ioctl	= compat_ptr_ioctl,

	.uring_cmd	= nvme_ns_head_chr_uring_cmd,

};



static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)

drivers/nvme/host/nvme.h

+4 −0
Original line number Diff line number Diff line
@@ -782,6 +782,10 @@ 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(struct io_uring_cmd *ioucmd,

		unsigned int issue_flags);

int nvme_ns_head_chr_uring_cmd(struct io_uring_cmd *ioucmd,

		unsigned int issue_flags);

int nvme_getgeo(struct block_device *bdev, struct hd_geometry *geo);



extern const struct attribute_group *nvme_ns_id_attr_groups[];

include/uapi/linux/nvme_ioctl.h

+25 −0
Original line number Diff line number Diff line
@@ -70,6 +70,28 @@ struct nvme_passthru_cmd64 { 
	__u64	result;

};



/* same as struct nvme_passthru_cmd64, minus the 8b result field */

struct nvme_uring_cmd {

	__u8	opcode;

	__u8	flags;

	__u16	rsvd1;

	__u32	nsid;

	__u32	cdw2;

	__u32	cdw3;

	__u64	metadata;

	__u64	addr;

	__u32	metadata_len;

	__u32	data_len;

	__u32	cdw10;

	__u32	cdw11;

	__u32	cdw12;

	__u32	cdw13;

	__u32	cdw14;

	__u32	cdw15;

	__u32	timeout_ms;

	__u32   rsvd2;

};



#define nvme_admin_cmd nvme_passthru_cmd



#define NVME_IOCTL_ID		_IO('N', 0x40)
@@ -83,4 +105,7 @@ struct nvme_passthru_cmd64 { 
#define NVME_IOCTL_IO64_CMD	_IOWR('N', 0x48, struct nvme_passthru_cmd64)

#define NVME_IOCTL_IO64_CMD_VEC	_IOWR('N', 0x49, struct nvme_passthru_cmd64)



/* io_uring async commands: */

#define NVME_URING_CMD_IO	_IOWR('N', 0x80, struct nvme_uring_cmd)



#endif /* _UAPI_LINUX_NVME_IOCTL_H */