fuse: add struct fuse_chan

The goal is to separate transport layer stuff out from struct fuse_conn,
leaving just the filesystem related members.

Add a new object referenced from fuse_conn.  This patch just implements the
allocation and freeing of this object.

Following patches will move transport related members from fuse_conn to
fuse_chan.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/cuse.c

@@ -51,6 +51,7 @@
 #include <linux/uio.h>
 #include <linux/user_namespace.h>
 
+#include "dev.h"
 #include "fuse_i.h"
 #include "fuse_dev_i.h"
 
@@ -504,8 +505,12 @@ static int cuse_channel_open(struct inode *inode, struct file *file)
 {
 	struct fuse_dev *fud;
 	struct cuse_conn *cc;
+	struct fuse_chan *fch __free(fuse_chan_free) = fuse_chan_new();
 	int rc;
 
+	if (!fch)
+		return -ENOMEM;
+
 	/* set up cuse_conn */
 	cc = kzalloc_obj(*cc);
 	if (!cc)
@@ -516,7 +521,7 @@ static int cuse_channel_open(struct inode *inode, struct file *file)
 	 * be represented in file->f_cred->user_ns.
 	 */
 	fuse_conn_init(&cc->fc, &cc->fm, file->f_cred->user_ns,
-		       &fuse_dev_fiq_ops, NULL);
+		       &fuse_dev_fiq_ops, NULL, no_free_ptr(fch));
 
 	cc->fc.release = cuse_fc_release;
 	fud = fuse_dev_alloc_install(&cc->fc);

fs/fuse/dev.c

@@ -6,6 +6,7 @@
   See the file COPYING.
 */
 
+#include "dev.h"
 #include "dev_uring_i.h"
 #include "fuse_i.h"
 #include "fuse_dev_i.h"
@@ -320,6 +321,18 @@ const struct fuse_iqueue_ops fuse_dev_fiq_ops = {
 };
 EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops);
 
+void fuse_chan_free(struct fuse_chan *fch)
+{
+	kfree(fch);
+}
+EXPORT_SYMBOL_GPL(fuse_chan_free);
+
+struct fuse_chan *fuse_chan_new(void)
+{
+	return kzalloc_obj(struct fuse_chan);
+}
+EXPORT_SYMBOL_GPL(fuse_chan_new);
+
 static void fuse_send_one(struct fuse_iqueue *fiq, struct fuse_req *req)
 {
 	req->in.h.len = sizeof(struct fuse_in_header) +

fs/fuse/dev.h

@@ -3,7 +3,14 @@
 #ifndef _FS_FUSE_DEV_H
 #define _FS_FUSE_DEV_H
 
+#include <linux/cleanup.h>
+
 struct fuse_conn;
+struct fuse_chan;
+
+struct fuse_chan *fuse_chan_new(void);
+void fuse_chan_free(struct fuse_chan *fch);
+DEFINE_FREE(fuse_chan_free, struct fuse_chan *, if (_T) fuse_chan_free(_T))
 
 void fuse_init_server_timeout(struct fuse_conn *fc, unsigned int timeout);
 

fs/fuse/fuse_dev_i.h

@@ -21,6 +21,10 @@ struct fuse_req;
 struct fuse_iqueue;
 struct fuse_forget_link;
 
+struct fuse_chan {
+	/* will move stuff from struct fuse_conn */
+};
+
 struct fuse_copy_state {
 	struct fuse_req *req;
 	struct iov_iter *iter;

fs/fuse/fuse_i.h

@@ -668,6 +668,9 @@ struct fuse_conn {
 	/** Input queue */
 	struct fuse_iqueue iq;
 
+	/* transport layer object */
+	struct fuse_chan *chan;
+
 	/** The next unique kernel file handle */
 	atomic64_t khctr;
 
@@ -1313,7 +1316,8 @@ void fuse_pqueue_init(struct fuse_pqueue *fpq);
  */
 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
 		    struct user_namespace *user_ns,
-		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv);
+		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv,
+		    struct fuse_chan *fch);
 
 /**
  * Release reference to fuse_conn

fs/fuse/inode.c

@@ -997,7 +997,7 @@ void fuse_pqueue_init(struct fuse_pqueue *fpq)
 
 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
 		    struct user_namespace *user_ns,
-		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
+		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv, struct fuse_chan *fch)
 {
 	memset(fc, 0, sizeof(*fc));
 	spin_lock_init(&fc->lock);
@@ -1035,6 +1035,7 @@ void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
 	INIT_LIST_HEAD(&fc->mounts);
 	list_add(&fm->fc_entry, &fc->mounts);
 	fm->fc = fc;
+	fc->chan = fch;
 }
 EXPORT_SYMBOL_GPL(fuse_conn_init);
 
@@ -1043,6 +1044,7 @@ static void delayed_release(struct rcu_head *p)
 	struct fuse_conn *fc = container_of(p, struct fuse_conn, rcu);
 
 	fuse_uring_destruct(fc);
+	fuse_chan_free(fc->chan);
 
 	put_user_ns(fc->user_ns);
 	fc->release(fc);
@@ -1983,8 +1985,12 @@ static int fuse_get_tree(struct fs_context *fsc)
 	struct fuse_conn *fc;
 	struct fuse_mount *fm;
 	struct super_block *sb;
+	struct fuse_chan *fch __free(fuse_chan_free) = fuse_chan_new();
 	int err;
 
+	if (!fch)
+		return -ENOMEM;
+
 	fc = kmalloc_obj(*fc);
 	if (!fc)
 		return -ENOMEM;
@@ -1995,7 +2001,7 @@ static int fuse_get_tree(struct fs_context *fsc)
 		return -ENOMEM;
 	}
 
-	fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL);
+	fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL, no_free_ptr(fch));
 	fc->release = fuse_free_conn;
 
 	fsc->s_fs_info = fm;

fs/fuse/virtio_fs.c

@@ -19,6 +19,7 @@
 #include <linux/highmem.h>
 #include <linux/cleanup.h>
 #include <linux/uio.h>
+#include "dev.h"
 #include "fuse_i.h"
 #include "fuse_dev_i.h"
 
@@ -1683,8 +1684,12 @@ static int virtio_fs_get_tree(struct fs_context *fsc)
 	struct fuse_conn *fc = NULL;
 	struct fuse_mount *fm;
 	unsigned int virtqueue_size;
+	struct fuse_chan *fch __free(fuse_chan_free) = fuse_chan_new();
 	int err = -EIO;
 
+	if (!fch)
+		return -ENOMEM;
+
 	if (!fsc->source)
 		return invalf(fsc, "No source specified");
 
@@ -1711,7 +1716,8 @@ static int virtio_fs_get_tree(struct fs_context *fsc)
 	if (!fm)
 		goto out_err;
 
-	fuse_conn_init(fc, fm, fsc->user_ns, &virtio_fs_fiq_ops, fs);
+	fuse_conn_init(fc, fm, fsc->user_ns, &virtio_fs_fiq_ops, fs, no_free_ptr(fch));
+
 	fc->release = fuse_free_conn;
 	fc->delete_stale = true;
 	fc->auto_submounts = true;