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 | 311 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 311 insertions(+)
diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c
index 48b1118b64f4..5269b3f8891e 100644
--- a/fs/fuse/dev_uring.c
+++ b/fs/fuse/dev_uring.c
@@ -31,12 +31,23 @@
#include <linux/topology.h>
#include <linux/io_uring/cmd.h>
+static void fuse_uring_req_end_and_get_next(struct fuse_ring_ent *ring_ent,
+ bool set_err, int error,
+ unsigned int issue_flags);
+
static void fuse_ring_ring_ent_unset_userspace(struct fuse_ring_ent *ent)
{
clear_bit(FRRS_USERSPACE, &ent->state);
list_del_init(&ent->list);
}
+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)
{
@@ -350,6 +361,188 @@ int fuse_uring_queue_cfg(struct fuse_ring *ring,
return 0;
}
+/*
+ * Checks for errors and stores it into the request
+ */
+static int fuse_uring_ring_ent_has_err(struct fuse_ring *ring,
+ struct fuse_ring_ent *ring_ent)
+{
+ struct fuse_conn *fc = ring->fc;
+ struct fuse_req *req = ring_ent->fuse_req;
+ struct fuse_out_header *oh = &req->out.h;
+ 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;
+}
+
+/*
+ * Copy data from the ring buffer to the fuse request
+ */
+static int fuse_uring_copy_from_ring(struct fuse_ring *ring,
+ struct fuse_req *req,
+ struct fuse_ring_req *rreq)
+{
+ struct fuse_copy_state cs;
+ struct fuse_args *args = req->args;
+
+ fuse_copy_init(&cs, 0, NULL);
+ cs.is_uring = 1;
+ cs.ring.buf = rreq->in_out_arg;
+
+ if (rreq->in_out_arg_len > ring->req_arg_len) {
+ pr_devel("Max ring buffer len exceeded (%u vs %zu\n",
+ rreq->in_out_arg_len, ring->req_arg_len);
+ return -EINVAL;
+ }
+ cs.ring.buf_sz = rreq->in_out_arg_len;
+ cs.req = req;
+
+ pr_devel("%s:%d buf=%p len=%d args=%d\n", __func__, __LINE__,
+ cs.ring.buf, cs.ring.buf_sz, args->out_numargs);
+
+ return fuse_copy_out_args(&cs, args, rreq->in_out_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_req *rreq)
+{
+ struct fuse_copy_state cs;
+ struct fuse_args *args = req->args;
+ int err;
+
+ fuse_copy_init(&cs, 1, NULL);
+ cs.is_uring = 1;
+ cs.ring.buf = rreq->in_out_arg;
+ cs.ring.buf_sz = ring->req_arg_len;
+ cs.req = req;
+
+ pr_devel("%s:%d buf=%p len=%d args=%d\n", __func__, __LINE__,
+ cs.ring.buf, cs.ring.buf_sz, args->out_numargs);
+
+ err = fuse_copy_args(&cs, args->in_numargs, args->in_pages,
+ (struct fuse_arg *)args->in_args, 0);
+ rreq->in_out_arg_len = cs.ring.offset;
+
+ pr_devel("%s:%d buf=%p len=%d args=%d err=%d\n", __func__, __LINE__,
+ cs.ring.buf, cs.ring.buf_sz, args->out_numargs, 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 void fuse_uring_send_to_ring(struct fuse_ring_ent *ring_ent,
+ unsigned int issue_flags, bool send_in_task)
+{
+ struct fuse_ring *ring = ring_ent->queue->ring;
+ struct fuse_ring_req *rreq = ring_ent->rreq;
+ struct fuse_req *req = ring_ent->fuse_req;
+ struct fuse_ring_queue *queue = ring_ent->queue;
+ int err = 0;
+
+ spin_lock(&queue->lock);
+
+ if (WARN_ON(test_bit(FRRS_USERSPACE, &ring_ent->state) ||
+ (test_bit(FRRS_FREED, &ring_ent->state)))) {
+ pr_err("qid=%d tag=%d ring-req=%p buf_req=%p invalid state %lu on send\n",
+ queue->qid, ring_ent->tag, ring_ent, rreq,
+ ring_ent->state);
+ err = -EIO;
+ } else {
+ set_bit(FRRS_USERSPACE, &ring_ent->state);
+ list_add(&ring_ent->list, &queue->ent_in_userspace);
+ }
+
+ spin_unlock(&queue->lock);
+ if (err)
+ goto err;
+
+ err = fuse_uring_copy_to_ring(ring, req, rreq);
+ if (unlikely(err)) {
+ spin_lock(&queue->lock);
+ fuse_ring_ring_ent_unset_userspace(ring_ent);
+ spin_unlock(&queue->lock);
+ goto err;
+ }
+
+ /* ring req go directly into the shared memory buffer */
+ rreq->in = req->in.h;
+ set_bit(FR_SENT, &req->flags);
+
+ pr_devel("%s qid=%d tag=%d state=%lu cmd-done op=%d unique=%llu issue_flags=%u\n",
+ __func__, ring_ent->queue->qid, ring_ent->tag, ring_ent->state,
+ rreq->in.opcode, rreq->in.unique, issue_flags);
+
+ if (send_in_task)
+ io_uring_cmd_complete_in_task(ring_ent->cmd,
+ fuse_uring_async_send_to_ring);
+ else
+ io_uring_cmd_done(ring_ent->cmd, 0, 0, issue_flags);
+
+ return;
+
+err:
+ fuse_uring_req_end_and_get_next(ring_ent, true, err, issue_flags);
+}
+
/*
* Put a ring request onto hold, it is no longer used for now.
*/
@@ -381,6 +574,104 @@ static void fuse_uring_ent_avail(struct fuse_ring_ent *ring_ent,
set_bit(FRRS_WAIT, &ring_ent->state);
}
+/*
+ * 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)
+{
+ clear_bit(FRRS_WAIT, &ring_ent->state);
+ list_del_init(&req->list);
+ clear_bit(FR_PENDING, &req->flags);
+ ring_ent->fuse_req = req;
+ set_bit(FRRS_FUSE_REQ, &ring_ent->state);
+}
+
+/*
+ * Release a uring entry and fetch the next fuse request if available
+ *
+ * @return true if a new request has been fetched
+ */
+static bool fuse_uring_ent_release_and_fetch(struct fuse_ring_ent *ring_ent)
+{
+ 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;
+
+ spin_lock(&ring_ent->queue->lock);
+ fuse_uring_ent_avail(ring_ent, queue);
+ 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);
+ }
+ spin_unlock(&ring_ent->queue->lock);
+
+ return req ? true : false;
+}
+
+/*
+ * Finalize a fuse request, then fetch and send the next entry, if available
+ *
+ * has lock/unlock/lock to avoid holding the lock on calling fuse_request_end
+ */
+static void fuse_uring_req_end_and_get_next(struct fuse_ring_ent *ring_ent,
+ bool set_err, int error,
+ unsigned int issue_flags)
+{
+ struct fuse_req *req = ring_ent->fuse_req;
+ int has_next;
+
+ 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;
+ clear_bit(FRRS_FUSE_REQ, &ring_ent->state);
+
+ has_next = fuse_uring_ent_release_and_fetch(ring_ent);
+ if (has_next) {
+ /* called within uring context - use provided flags */
+ fuse_uring_send_to_ring(ring_ent, issue_flags, 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_and_release(struct fuse_dev *fud,
+ struct fuse_ring_ent *ring_ent,
+ unsigned int issue_flags)
+{
+ struct fuse_ring_req *rreq = ring_ent->rreq;
+ struct fuse_req *req = ring_ent->fuse_req;
+ ssize_t err = 0;
+ bool set_err = false;
+
+ req->out.h = rreq->out;
+
+ err = fuse_uring_ring_ent_has_err(fud->fc->ring, ring_ent);
+ 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(fud->fc->ring, req, rreq);
+ 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_and_get_next(ring_ent, set_err, err, issue_flags);
+}
+
/*
* fuse_uring_req_fetch command handling
*/
@@ -566,6 +857,26 @@ int fuse_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
spin_unlock(&queue->lock);
break;
+ case FUSE_URING_REQ_COMMIT_AND_FETCH:
+ if (unlikely(!ring->ready)) {
+ pr_info("commit and fetch, but fuse-uringis not ready.");
+ goto err_unlock;
+ }
+
+ if (!test_bit(FRRS_USERSPACE, &ring_ent->state)) {
+ pr_info("qid=%d tag=%d state %lu SQE already handled\n",
+ queue->qid, ring_ent->tag, ring_ent->state);
+ goto err_unlock;
+ }
+
+ fuse_ring_ring_ent_unset_userspace(ring_ent);
+ spin_unlock(&queue->lock);
+
+ WRITE_ONCE(ring_ent->cmd, cmd);
+ fuse_uring_commit_and_release(fud, ring_ent, issue_flags);
+
+ ret = 0;
+ break;
default:
ret = -EINVAL;
pr_devel("Unknown uring command %d", cmd_op);
--
2.40.1
