nvme: wire-up uring-cmd support for io-passthru on char-device.
authorKanchan Joshi <joshi.k@samsung.com>
Wed, 11 May 2022 05:47:48 +0000 (11:17 +0530)
committerJens Axboe <axboe@kernel.dk>
Wed, 11 May 2022 13:41:13 +0000 (07:41 -0600)
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: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220511054750.20432-5-joshi.k@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
drivers/nvme/host/core.c
drivers/nvme/host/ioctl.c
drivers/nvme/host/multipath.c
drivers/nvme/host/nvme.h
include/uapi/linux/nvme_ioctl.h

index e1846d04817f373d89c4e1cf28095ac9eb6346e8..682df98db341215ea833e0c0b73f5d757c114bc1 100644 (file)
@@ -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)
index 8d2569b656cce6bad44dba92d05000d33d5ce6d5..92d695262d8fc99ce40342798690086d1ce8eadd 100644 (file)
@@ -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 @@ out_unlock:
        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)
index d464fdf978fbaa449cd353f8b4972bfd4d62f29c..d3e2440d8abb059b44dcab8c32a184e7710f0778 100644 (file)
@@ -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)
index a2b53ca6333590dd7e4cb754435761549a3b1105..086ccbdd700346b9e3e7fe20dd00950f450588b5 100644 (file)
@@ -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[];
index b2e43185e3b5562cc17015d5d5274aa4552af92b..04e458c649abab12f4002387c64c87df2ae4d2fb 100644 (file)
@@ -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 */