[RFC PATCH v3 3/3] nvme: wire up support for async passthrough
Kanchan Joshi
joshi.k at samsung.com
Tue Mar 16 14:01:26 GMT 2021
Introduce handler for mq_ops->uring_cmd(), implementing async
passthrough on block-device.
Signed-off-by: Kanchan Joshi <joshi.k at samsung.com>
---
drivers/nvme/host/core.c | 180 ++++++++++++++++++++++++++++++++++-----
drivers/nvme/host/nvme.h | 3 +
drivers/nvme/host/pci.c | 1 +
3 files changed, 162 insertions(+), 22 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 46c1bb7a89f0..c4f0e54fe9a5 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1053,6 +1053,88 @@ static void *nvme_add_user_metadata(struct bio *bio, void __user *ubuf,
return ERR_PTR(ret);
}
+/*
+ * Convert integer values from ioctl structures to user pointers, silently
+ * ignoring the upper bits in the compat case to match behaviour of 32-bit
+ * kernels.
+ */
+static void __user *nvme_to_user_ptr(uintptr_t ptrval)
+{
+ if (in_compat_syscall())
+ ptrval = (compat_uptr_t)ptrval;
+ return (void __user *)ptrval;
+}
+/*
+ * This is carved within the block_uring_cmd, to avoid dynamic allocation.
+ * Care should be taken not to grow this beyond what is available.
+ */
+struct uring_cmd_data {
+ union {
+ struct bio *bio;
+ u64 result; /* nvme cmd result */
+ };
+ void *meta; /* kernel-resident buffer */
+ int status; /* nvme cmd status */
+};
+
+inline u64 *ucmd_data_addr(struct io_uring_cmd *ioucmd)
+{
+ return &(((struct block_uring_cmd *)&ioucmd->pdu)->unused[0]);
+}
+
+void ioucmd_task_cb(struct io_uring_cmd *ioucmd)
+{
+ struct uring_cmd_data *ucd;
+ struct nvme_passthru_cmd __user *ptcmd;
+ struct block_uring_cmd *bcmd;
+
+ bcmd = (struct block_uring_cmd *) &ioucmd->pdu;
+ ptcmd = (void __user *) bcmd->addr;
+ ucd = (struct uring_cmd_data *) ucmd_data_addr(ioucmd);
+
+ /* handle meta update */
+ if (ucd->meta) {
+ void __user *umeta = nvme_to_user_ptr(ptcmd->metadata);
+
+ if (!ucd->status)
+ if (copy_to_user(umeta, ucd->meta, ptcmd->metadata_len))
+ ucd->status = -EFAULT;
+ kfree(ucd->meta);
+ }
+ /* handle result update */
+ if (put_user(ucd->result, (u32 __user *)&ptcmd->result))
+ ucd->status = -EFAULT;
+ io_uring_cmd_done(ioucmd, ucd->status);
+}
+
+void nvme_end_async_pt(struct request *req, blk_status_t err)
+{
+ struct io_uring_cmd *ioucmd;
+ struct uring_cmd_data *ucd;
+ struct bio *bio;
+ int ret;
+
+ ioucmd = req->end_io_data;
+ ucd = (struct uring_cmd_data *) ucmd_data_addr(ioucmd);
+ /* extract bio before reusing the same field for status */
+ bio = ucd->bio;
+
+ if (nvme_req(req)->flags & NVME_REQ_CANCELLED)
+ ucd->status = -EINTR;
+ else
+ ucd->status = nvme_req(req)->status;
+ ucd->result = le64_to_cpu(nvme_req(req)->result.u64);
+
+ /* this takes care of setting up task-work */
+ ret = uring_cmd_complete_in_task(ioucmd, ioucmd_task_cb);
+ if (ret < 0)
+ kfree(ucd->meta);
+
+ /* unmap pages, free bio, nvme command and request */
+ blk_rq_unmap_user(bio);
+ blk_mq_free_request(req);
+}
+
static u32 nvme_known_admin_effects(u8 opcode)
{
switch (opcode) {
@@ -1140,10 +1222,27 @@ void nvme_execute_passthru_rq(struct request *rq)
}
EXPORT_SYMBOL_NS_GPL(nvme_execute_passthru_rq, NVME_TARGET_PASSTHRU);
+static void nvme_setup_uring_cmd_data(struct request *rq,
+ struct io_uring_cmd *ioucmd, void *meta, bool write)
+{
+ struct uring_cmd_data *ucd;
+
+ ucd = (struct uring_cmd_data *) ucmd_data_addr(ioucmd);
+ /* to free bio on completion, as req->bio will be null at that time */
+ ucd->bio = rq->bio;
+ /* meta update is required only for read requests */
+ if (meta && !write)
+ ucd->meta = meta;
+ else
+ ucd->meta = NULL;
+ rq->end_io_data = ioucmd;
+}
+
static int nvme_submit_user_cmd(struct request_queue *q,
struct nvme_command *cmd, void __user *ubuffer,
unsigned bufflen, void __user *meta_buffer, unsigned meta_len,
- u32 meta_seed, u64 *result, unsigned timeout)
+ u32 meta_seed, u64 *result, unsigned int timeout,
+ struct io_uring_cmd *ioucmd)
{
bool write = nvme_is_write(cmd);
struct nvme_ns *ns = q->queuedata;
@@ -1179,6 +1278,20 @@ static int nvme_submit_user_cmd(struct request_queue *q,
req->cmd_flags |= REQ_INTEGRITY;
}
}
+ if (ioucmd) { /* async handling */
+ u32 effects;
+
+ effects = nvme_command_effects(ns->ctrl, ns, cmd->common.opcode);
+ /* filter commands with non-zero effects, keep it simple for now*/
+ if (effects) {
+ ret = -EOPNOTSUPP;
+ goto out_unmap;
+ }
+ nvme_setup_uring_cmd_data(req, ioucmd, meta, write);
+ blk_execute_rq_nowait(ns ? ns->disk : NULL, req, 0,
+ nvme_end_async_pt);
+ return 0;
+ }
nvme_execute_passthru_rq(req);
if (nvme_req(req)->flags & NVME_REQ_CANCELLED)
@@ -1544,18 +1657,6 @@ static void nvme_enable_aen(struct nvme_ctrl *ctrl)
queue_work(nvme_wq, &ctrl->async_event_work);
}
-/*
- * Convert integer values from ioctl structures to user pointers, silently
- * ignoring the upper bits in the compat case to match behaviour of 32-bit
- * kernels.
- */
-static void __user *nvme_to_user_ptr(uintptr_t ptrval)
-{
- if (in_compat_syscall())
- ptrval = (compat_uptr_t)ptrval;
- return (void __user *)ptrval;
-}
-
static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
{
struct nvme_user_io io;
@@ -1616,11 +1717,13 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
return nvme_submit_user_cmd(ns->queue, &c,
nvme_to_user_ptr(io.addr), length,
- metadata, meta_len, lower_32_bits(io.slba), NULL, 0);
+ metadata, meta_len, lower_32_bits(io.slba), NULL, 0,
+ NULL);
}
static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
- struct nvme_passthru_cmd __user *ucmd)
+ struct nvme_passthru_cmd __user *ucmd,
+ struct io_uring_cmd *ioucmd)
{
struct nvme_passthru_cmd cmd;
struct nvme_command c;
@@ -1654,9 +1757,9 @@ static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
status = nvme_submit_user_cmd(ns ? ns->queue : ctrl->admin_q, &c,
nvme_to_user_ptr(cmd.addr), cmd.data_len,
nvme_to_user_ptr(cmd.metadata), cmd.metadata_len,
- 0, &result, timeout);
+ 0, &result, timeout, ioucmd);
- if (status >= 0) {
+ if (!ioucmd && status >= 0) {
if (put_user(result, &ucmd->result))
return -EFAULT;
}
@@ -1698,7 +1801,7 @@ static int nvme_user_cmd64(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
status = nvme_submit_user_cmd(ns ? ns->queue : ctrl->admin_q, &c,
nvme_to_user_ptr(cmd.addr), cmd.data_len,
nvme_to_user_ptr(cmd.metadata), cmd.metadata_len,
- 0, &cmd.result, timeout);
+ 0, &cmd.result, timeout, NULL);
if (status >= 0) {
if (put_user(cmd.result, &ucmd->result))
@@ -1760,7 +1863,7 @@ static int nvme_handle_ctrl_ioctl(struct nvme_ns *ns, unsigned int cmd,
switch (cmd) {
case NVME_IOCTL_ADMIN_CMD:
- ret = nvme_user_cmd(ctrl, NULL, argp);
+ ret = nvme_user_cmd(ctrl, NULL, argp, NULL);
break;
case NVME_IOCTL_ADMIN64_CMD:
ret = nvme_user_cmd64(ctrl, NULL, argp);
@@ -1799,7 +1902,7 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
ret = ns->head->ns_id;
break;
case NVME_IOCTL_IO_CMD:
- ret = nvme_user_cmd(ns->ctrl, ns, argp);
+ ret = nvme_user_cmd(ns->ctrl, ns, argp, NULL);
break;
case NVME_IOCTL_SUBMIT_IO:
ret = nvme_submit_io(ns, argp);
@@ -1818,6 +1921,39 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
return ret;
}
+int nvme_uring_cmd(struct request_queue *q, struct io_uring_cmd *ioucmd,
+ enum io_uring_cmd_flags flags)
+{
+ struct nvme_ns_head *head = NULL;
+ struct block_device *bdev = I_BDEV(ioucmd->file->f_mapping->host);
+ struct block_uring_cmd *bcmd = (struct block_uring_cmd *)&ioucmd->pdu;
+ struct nvme_ns *ns;
+ int srcu_idx, ret;
+ void __user *argp = (void __user *) bcmd->addr;
+
+ BUILD_BUG_ON(sizeof(struct uring_cmd_data) >
+ sizeof(struct block_uring_cmd) -
+ offsetof(struct block_uring_cmd, unused));
+
+ ns = nvme_get_ns_from_disk(bdev->bd_disk, &head, &srcu_idx);
+ if (unlikely(!ns))
+ return -EWOULDBLOCK;
+
+ switch (bcmd->ioctl_cmd) {
+ case NVME_IOCTL_IO_CMD:
+ ret = nvme_user_cmd(ns->ctrl, ns, argp, ioucmd);
+ break;
+ default:
+ ret = -ENOTTY;
+ }
+
+ if (ret >= 0)
+ ret = -EIOCBQUEUED;
+ nvme_put_ns_from_disk(head, srcu_idx);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nvme_uring_cmd);
+
#ifdef CONFIG_COMPAT
struct nvme_user_io32 {
__u8 opcode;
@@ -3309,7 +3445,7 @@ static int nvme_dev_user_cmd(struct nvme_ctrl *ctrl, void __user *argp)
kref_get(&ns->kref);
up_read(&ctrl->namespaces_rwsem);
- ret = nvme_user_cmd(ctrl, ns, argp);
+ ret = nvme_user_cmd(ctrl, ns, argp, NULL);
nvme_put_ns(ns);
return ret;
@@ -3326,7 +3462,7 @@ static long nvme_dev_ioctl(struct file *file, unsigned int cmd,
switch (cmd) {
case NVME_IOCTL_ADMIN_CMD:
- return nvme_user_cmd(ctrl, NULL, argp);
+ return nvme_user_cmd(ctrl, NULL, argp, NULL);
case NVME_IOCTL_ADMIN64_CMD:
return nvme_user_cmd64(ctrl, NULL, argp);
case NVME_IOCTL_IO_CMD:
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 0254aa611dfa..f3daee4a4848 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -19,6 +19,7 @@
#include <linux/t10-pi.h>
#include <trace/events/block.h>
+#include <linux/io_uring.h>
extern unsigned int nvme_io_timeout;
#define NVME_IO_TIMEOUT (nvme_io_timeout * HZ)
@@ -620,6 +621,8 @@ int nvme_wait_freeze_timeout(struct nvme_ctrl *ctrl, long timeout);
void nvme_start_freeze(struct nvme_ctrl *ctrl);
#define NVME_QID_ANY -1
+int nvme_uring_cmd(struct request_queue *q, struct io_uring_cmd *ucmd,
+ enum io_uring_cmd_flags flags);
struct request *nvme_alloc_request(struct request_queue *q,
struct nvme_command *cmd, blk_mq_req_flags_t flags);
void nvme_cleanup_cmd(struct request *req);
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 7b6632c00ffd..6c84dc964259 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1629,6 +1629,7 @@ static const struct blk_mq_ops nvme_mq_ops = {
.map_queues = nvme_pci_map_queues,
.timeout = nvme_timeout,
.poll = nvme_poll,
+ .uring_cmd = nvme_uring_cmd,
};
static void nvme_dev_remove_admin(struct nvme_dev *dev)
--
2.25.1
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