This adds support for fuse request completion through ring SQEs
(FUSE_URING_REQ_COMMIT_AND_FETCH handling). After committing
the ring entry it becomes available for new fuse requests.
Handling of requests through the ring (SQE/CQE handling)
is complete now.
Fuse request data are copied through the mmaped ring buffer,
there is no support for any zero copy yet.
Signed-off-by: Bernd Schubert <bschubert@xxxxxxx>
---
fs/fuse/dev_uring.c | 407 ++++++++++++++++++++++++++++++++++++++++++++++++++
fs/fuse/dev_uring_i.h | 21 +++
2 files changed, 428 insertions(+)
diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c
index 46c2274193bf..96347751668e 100644
--- a/fs/fuse/dev_uring.c
+++ b/fs/fuse/dev_uring.c
@@ -29,6 +29,26 @@
#include <linux/topology.h>
#include <linux/io_uring/cmd.h>
+struct fuse_uring_cmd_pdu {
+ struct fuse_ring_ent *ring_ent;
+};
+
+/*
+ * Finalize a fuse request, then fetch and send the next entry, if available
+ */
+static void fuse_uring_req_end(struct fuse_ring_ent *ring_ent,
+ bool set_err, int error)
+{
+ struct fuse_req *req = ring_ent->fuse_req;
+
+ if (set_err)
+ req->out.h.error = error;
+
+ clear_bit(FR_SENT, &req->flags);
+ fuse_request_end(ring_ent->fuse_req);
+ ring_ent->fuse_req = NULL;
+}
+
static int fuse_ring_ring_ent_unset_userspace(struct fuse_ring_ent *ent)
{
if (WARN_ON_ONCE(ent->state != FRRS_USERSPACE))
@@ -40,6 +60,13 @@ static int fuse_ring_ring_ent_unset_userspace(struct fuse_ring_ent *ent)
return 0;
}
+static void
+fuse_uring_async_send_to_ring(struct io_uring_cmd *cmd,
+ unsigned int issue_flags)
+{
+ io_uring_cmd_done(cmd, 0, 0, issue_flags);
+}
+
/* Update conn limits according to ring values */
static void fuse_uring_conn_cfg_limits(struct fuse_ring *ring)
{
@@ -65,6 +92,9 @@ static void fuse_uring_queue_cfg(struct fuse_ring_queue *queue, int qid,
INIT_LIST_HEAD(&queue->sync_ent_avail_queue);
INIT_LIST_HEAD(&queue->async_ent_avail_queue);
+ INIT_LIST_HEAD(&queue->ent_in_userspace);
+ INIT_LIST_HEAD(&queue->sync_fuse_req_queue);
+ INIT_LIST_HEAD(&queue->async_fuse_req_queue);
for (tag = 0; tag < ring->queue_depth; tag++) {
struct fuse_ring_ent *ent = &queue->ring_ent[tag];
@@ -173,6 +203,200 @@ int fuse_uring_conn_cfg(struct file *file, void __user *argp)
return res;
}
+/*
+ * Checks for errors and stores it into the request
+ */
+static int fuse_uring_out_header_has_err(struct fuse_out_header *oh,
+ struct fuse_req *req,
+ struct fuse_conn *fc)
+{
+ int err;
+
+ if (oh->unique == 0) {
+ /* Not supportd through request based uring, this needs another
+ * ring from user space to kernel
+ */
+ pr_warn("Unsupported fuse-notify\n");
+ err = -EINVAL;
+ goto seterr;
+ }
+
+ if (oh->error <= -512 || oh->error > 0) {
+ err = -EINVAL;
+ goto seterr;
+ }
+
+ if (oh->error) {
+ err = oh->error;
+ pr_devel("%s:%d err=%d op=%d req-ret=%d", __func__, __LINE__,
+ err, req->args->opcode, req->out.h.error);
+ goto err; /* error already set */
+ }
+
+ if ((oh->unique & ~FUSE_INT_REQ_BIT) != req->in.h.unique) {
+ pr_warn("Unpexted seqno mismatch, expected: %llu got %llu\n",
+ req->in.h.unique, oh->unique & ~FUSE_INT_REQ_BIT);
+ err = -ENOENT;
+ goto seterr;
+ }
+
+ /* Is it an interrupt reply ID? */
+ if (oh->unique & FUSE_INT_REQ_BIT) {
+ err = 0;
+ if (oh->error == -ENOSYS)
+ fc->no_interrupt = 1;
+ else if (oh->error == -EAGAIN) {
+ /* XXX Interrupts not handled yet */
+ /* err = queue_interrupt(req); */
+ pr_warn("Intrerupt EAGAIN not supported yet");
+ err = -EINVAL;
+ }
+
+ goto seterr;
+ }
+
+ return 0;
+
+seterr:
+ pr_devel("%s:%d err=%d op=%d req-ret=%d", __func__, __LINE__, err,
+ req->args->opcode, req->out.h.error);
+ oh->error = err;
+err:
+ pr_devel("%s:%d err=%d op=%d req-ret=%d", __func__, __LINE__, err,
+ req->args->opcode, req->out.h.error);
+ return err;
+}
+
+static int fuse_uring_copy_from_ring(struct fuse_ring *ring,
+ struct fuse_req *req,
+ struct fuse_ring_ent *ent)
+{
+ struct fuse_ring_req __user *rreq = ent->rreq;
+ struct fuse_copy_state cs;
+ struct fuse_args *args = req->args;
+ struct iov_iter iter;
+ int err;
+ int res_arg_len;
+
+ err = copy_from_user(&res_arg_len, &rreq->in_out_arg_len,
+ sizeof(res_arg_len));
+ if (err)
+ return err;
+
+ err = import_ubuf(ITER_SOURCE, (void __user *)&rreq->in_out_arg,
+ ent->max_arg_len, &iter);
+ if (err)
+ return err;
+
+ fuse_copy_init(&cs, 0, &iter);
+ cs.is_uring = 1;
+ cs.req = req;
+
+ return fuse_copy_out_args(&cs, args, res_arg_len);
+}
+
+ /*
+ * Copy data from the req to the ring buffer
+ */
+static int fuse_uring_copy_to_ring(struct fuse_ring *ring, struct fuse_req *req,
+ struct fuse_ring_ent *ent)
+{
+ struct fuse_ring_req __user *rreq = ent->rreq;
+ struct fuse_copy_state cs;
+ struct fuse_args *args = req->args;
+ int err, res;
+ struct iov_iter iter;
+
+ err = import_ubuf(ITER_DEST, (void __user *)&rreq->in_out_arg,
+ ent->max_arg_len, &iter);
+ if (err) {
+ pr_info("Import user buffer failed\n");
+ return err;
+ }
+
+ fuse_copy_init(&cs, 1, &iter);
+ cs.is_uring = 1;
+ cs.req = req;
+ err = fuse_copy_args(&cs, args->in_numargs, args->in_pages,
+ (struct fuse_arg *)args->in_args, 0);
+ if (err) {
+ pr_info("%s fuse_copy_args failed\n", __func__);
+ return err;
+ }
+
+ BUILD_BUG_ON((sizeof(rreq->in_out_arg_len) != sizeof(cs.ring.offset)));
+ res = copy_to_user(&rreq->in_out_arg_len, &cs.ring.offset,
+ sizeof(rreq->in_out_arg_len));
+ err = res > 0 ? -EFAULT : res;
+
+ return err;
+}
+
+static int
+fuse_uring_prepare_send(struct fuse_ring_ent *ring_ent)
+{
+ struct fuse_ring_req *rreq = ring_ent->rreq;
+ struct fuse_ring_queue *queue = ring_ent->queue;
+ struct fuse_ring *ring = queue->ring;
+ struct fuse_req *req = ring_ent->fuse_req;
+ int err = 0, res;
+
+ if (WARN_ON(ring_ent->state != FRRS_FUSE_REQ)) {
+ pr_err("qid=%d tag=%d ring-req=%p buf_req=%p invalid state %d on send\n",
+ queue->qid, ring_ent->tag, ring_ent, rreq,
+ ring_ent->state);
+ err = -EIO;
+ }
+
+ if (err)
+ return err;
+
+ pr_devel("%s qid=%d tag=%d state=%d cmd-done op=%d unique=%llu\n",
+ __func__, queue->qid, ring_ent->tag, ring_ent->state,
+ req->in.h.opcode, req->in.h.unique);
+
+ /* copy the request */
+ err = fuse_uring_copy_to_ring(ring, req, ring_ent);
+ if (unlikely(err)) {
+ pr_info("Copy to ring failed: %d\n", err);
+ goto err;
+ }
+
+ /* copy fuse_in_header */
+ res = copy_to_user(&rreq->in, &req->in.h, sizeof(rreq->in));
+ err = res > 0 ? -EFAULT : res;
+ if (err)
+ goto err;
+
+ set_bit(FR_SENT, &req->flags);
+ return 0;
+
+err:
+ fuse_uring_req_end(ring_ent, true, err);
+ return err;
+}
+
+/*
+ * Write data to the ring buffer and send the request to userspace,
+ * userspace will read it
+ * This is comparable with classical read(/dev/fuse)
+ */
+static int fuse_uring_send_next_to_ring(struct fuse_ring_ent *ring_ent)
+{
+ int err = 0;
+
+ err = fuse_uring_prepare_send(ring_ent);
+ if (err)
+ goto err;
+
+ io_uring_cmd_complete_in_task(ring_ent->cmd,
+ fuse_uring_async_send_to_ring);
+ return 0;
+
+err:
+ return err;
+}
+
/*
* Put a ring request onto hold, it is no longer used for now.
*/
@@ -206,6 +430,166 @@ static void fuse_uring_ent_avail(struct fuse_ring_ent *ring_ent,
ring_ent->state = FRRS_WAIT;
}
+/*
+ * Assign a fuse queue entry to the given entry
+ */
+static void fuse_uring_add_req_to_ring_ent(struct fuse_ring_ent *ring_ent,
+ struct fuse_req *req)
+{
+ lockdep_assert_held(&ring_ent->queue->lock);
+
+ if (WARN_ON_ONCE(ring_ent->state != FRRS_WAIT &&
+ ring_ent->state != FRRS_COMMIT)) {
+ pr_warn("%s qid=%d tag=%d state=%d async=%d\n", __func__,
+ ring_ent->queue->qid, ring_ent->tag, ring_ent->state,
+ ring_ent->async);
+ }
+ list_del_init(&req->list);
+ clear_bit(FR_PENDING, &req->flags);
+ ring_ent->fuse_req = req;
+ ring_ent->state = FRRS_FUSE_REQ;
+}
+
+/*
+ * Release the ring entry and fetch the next fuse request if available
+ *
+ * @return true if a new request has been fetched
+ */
+static bool fuse_uring_ent_assign_req(struct fuse_ring_ent *ring_ent)
+ __must_hold(&queue->lock)
+{
+ struct fuse_req *req = NULL;
+ struct fuse_ring_queue *queue = ring_ent->queue;
+ struct list_head *req_queue = ring_ent->async ?
+ &queue->async_fuse_req_queue :
+ &queue->sync_fuse_req_queue;
+
+ lockdep_assert_held(&queue->lock);
+
+ /* get and assign the next entry while it is still holding the lock */
+ if (!list_empty(req_queue)) {
+ req = list_first_entry(req_queue, struct fuse_req, list);
+ fuse_uring_add_req_to_ring_ent(ring_ent, req);
+ list_del_init(&ring_ent->list);
+ }
+
+ return req ? true : false;
+}
+
+/*
+ * Read data from the ring buffer, which user space has written to
+ * This is comparible with handling of classical write(/dev/fuse).
+ * Also make the ring request available again for new fuse requests.
+ */
+static void fuse_uring_commit(struct fuse_ring_ent *ring_ent,
+ unsigned int issue_flags)
+{
+ struct fuse_ring *ring = ring_ent->queue->ring;
+ struct fuse_conn *fc = ring->fc;
+ struct fuse_ring_req *rreq = ring_ent->rreq;
+ struct fuse_req *req = ring_ent->fuse_req;
+ ssize_t err = 0;
+ bool set_err = false;
+
+ err = copy_from_user(&req->out.h, &rreq->out, sizeof(req->out.h));
+ if (err) {
+ req->out.h.error = err;
+ goto out;
+ }
+
+ err = fuse_uring_out_header_has_err(&req->out.h, req, fc);
+ if (err) {
+ /* req->out.h.error already set */
+ pr_devel("%s:%d err=%zd oh->err=%d\n", __func__, __LINE__, err,
+ req->out.h.error);
+ goto out;
+ }
+
+ err = fuse_uring_copy_from_ring(ring, req, ring_ent);
+ if (err)
+ set_err = true;
+
+out:
+ pr_devel("%s:%d ret=%zd op=%d req-ret=%d\n", __func__, __LINE__, err,
+ req->args->opcode, req->out.h.error);
+ fuse_uring_req_end(ring_ent, set_err, err);
+}
+
+/*
+ * Get the next fuse req and send it
+ */
+static void fuse_uring_next_fuse_req(struct fuse_ring_ent *ring_ent,
+ struct fuse_ring_queue *queue)
+{
+ int has_next, err;
+ int prev_state = ring_ent->state;
+
+ WARN_ON_ONCE(!list_empty(&ring_ent->list));
+
+ do {
+ spin_lock(&queue->lock);
+ has_next = fuse_uring_ent_assign_req(ring_ent);
+ if (!has_next) {
+ fuse_uring_ent_avail(ring_ent, queue);
+ spin_unlock(&queue->lock);
+ break; /* no request left */
+ }
+ spin_unlock(&queue->lock);
+
+ err = fuse_uring_send_next_to_ring(ring_ent);
+ if (err) {
+ ring_ent->state = prev_state;
+ continue;
+ }
+
+ err = 0;
+ spin_lock(&queue->lock);
+ ring_ent->state = FRRS_USERSPACE;
+ list_add(&ring_ent->list, &queue->ent_in_userspace);
+ spin_unlock(&queue->lock);
+ } while (err);
+}
+
+/* FUSE_URING_REQ_COMMIT_AND_FETCH handler */
+static int fuse_uring_commit_fetch(struct fuse_ring_ent *ring_ent,
+ struct io_uring_cmd *cmd, int issue_flags)
+__releases(ring_ent->queue->lock)
+{
+ int err;
+ struct fuse_ring_queue *queue = ring_ent->queue;
+ struct fuse_ring *ring = queue->ring;
+
+ err = -ENOTCONN;
+ if (unlikely(!ring->ready)) {
+ pr_info("commit and fetch, but fuse-uring is not ready.");
+ return err;
+ }
+
+ err = -EALREADY;
+ if (ring_ent->state != FRRS_USERSPACE) {
+ pr_info("qid=%d tag=%d state %d SQE already handled\n",
+ queue->qid, ring_ent->tag, ring_ent->state);
+ return err;
+ }
+
+ fuse_ring_ring_ent_unset_userspace(ring_ent);
+
+ ring_ent->cmd = cmd;
+ spin_unlock(&queue->lock);
+
+ /* without the queue lock, as other locks are taken */
+ fuse_uring_commit(ring_ent, issue_flags);
+
+ /*
+ * Fetching the next request is absolutely required as queued
+ * fuse requests would otherwise not get processed - committing
+ * and fetching is done in one step vs legacy fuse, which has separated
+ * read (fetch request) and write (commit result).
+ */
+ fuse_uring_next_fuse_req(ring_ent, queue);
+ return 0;
+}
+
/*
* fuse_uring_req_fetch command handling
*/
@@ -250,6 +634,7 @@ __must_hold(ring_ent->queue->lock)
return 0;
}
+/* FUSE_URING_REQ_FETCH handler */
static int fuse_uring_fetch(struct fuse_ring_ent *ring_ent,
struct io_uring_cmd *cmd, unsigned int issue_flags)
__releases(ring_ent->queue->lock)
@@ -339,10 +724,32 @@ int fuse_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
if (unlikely(fc->aborted || queue->stopped))
goto err_unlock;
+ ring_ent->rreq = (void __user *)cmd_req->buf_ptr;
+ ring_ent->max_arg_len = cmd_req->buf_len -
+ offsetof(struct fuse_ring_req, in_out_arg);
+ ret = -EINVAL;
+ if (cmd_req->buf_len < ring->req_buf_sz) {
+ pr_info("Invalid req buf len, expected: %zd got %d\n",
+ ring->req_buf_sz, cmd_req->buf_len);
+ goto err_unlock;
+ }
+
+ ring_ent->rreq = (void __user *)cmd_req->buf_ptr;
+ ring_ent->max_arg_len = cmd_req->buf_len -
+ offsetof(struct fuse_ring_req, in_out_arg);
+ if (cmd_req->buf_len < ring->req_buf_sz) {
+ pr_info("Invalid req buf len, expected: %zd got %d\n",
+ ring->req_buf_sz, cmd_req->buf_len);
+ goto err_unlock;
+ }
+
switch (cmd_op) {
case FUSE_URING_REQ_FETCH:
ret = fuse_uring_fetch(ring_ent, cmd, issue_flags);
break;
+ case FUSE_URING_REQ_COMMIT_AND_FETCH:
+ ret = fuse_uring_commit_fetch(ring_ent, cmd, issue_flags);
+ break;
default:
ret = -EINVAL;
pr_devel("Unknown uring command %d", cmd_op);
diff --git a/fs/fuse/dev_uring_i.h b/fs/fuse/dev_uring_i.h
index 6561f4178cac..697963e5d524 100644
--- a/fs/fuse/dev_uring_i.h
+++ b/fs/fuse/dev_uring_i.h
@@ -26,6 +26,9 @@ enum fuse_ring_req_state {
/* The ring request waits for a new fuse request */
FRRS_WAIT,
+ /* The ring req got assigned a fuse req */
+ FRRS_FUSE_REQ,
+
/* request is in or on the way to user space */
FRRS_USERSPACE,
};
@@ -47,6 +50,17 @@ struct fuse_ring_ent {
struct list_head list;
struct io_uring_cmd *cmd;
+
+ /* fuse_req assigned to the ring entry */
+ struct fuse_req *fuse_req;
+
+ /*
+ * buffer provided by fuse server
+ */
+ struct fuse_ring_req __user *rreq;
+
+ /* struct fuse_ring_req::in_out_arg size*/
+ size_t max_arg_len;
};
struct fuse_ring_queue {
@@ -69,6 +83,13 @@ struct fuse_ring_queue {
struct list_head async_ent_avail_queue;
struct list_head sync_ent_avail_queue;
+ /* fuse fg/bg request types */
+ struct list_head async_fuse_req_queue;
+ struct list_head sync_fuse_req_queue;
+
+ /* entries sent to userspace */
+ struct list_head ent_in_userspace;
+
/*
* available number of sync requests,
* loosely bound to fuse foreground requests
--
2.43.0
