From: Miklos Szeredi <mszeredi@redhat.com>
Date: Tue, 10 Sep 2019 15:04:10 +0200
Subject: cuse: convert init to simple api
Git-commit: b50ef7c52ad7c954b743cd1cb181e9bf03537bab
Patch-mainline: v5.4-rc1
References: jsc#SLE-13782

This is a straightforward conversion.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
 fs/fuse/cuse.c | 93 ++++++++++++++++++++++++++++++----------------------------
 1 file changed, 48 insertions(+), 45 deletions(-)

diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index d011a1ad1d4f..2332e7f960a8 100644
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -298,6 +298,14 @@ static void cuse_gendev_release(struct device *dev)
 	kfree(dev);
 }
 
+struct cuse_init_args {
+	struct fuse_args_pages ap;
+	struct cuse_init_in in;
+	struct cuse_init_out out;
+	struct page *page;
+	struct fuse_page_desc desc;
+};
+
 /**
  * cuse_process_init_reply - finish initializing CUSE channel
  *
@@ -305,21 +313,22 @@ static void cuse_gendev_release(struct device *dev)
  * required data structures for it.  Please read the comment at the
  * top of this file for high level overview.
  */
-static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
+static void cuse_process_init_reply(struct fuse_conn *fc,
+				    struct fuse_args *args, int error)
 {
+	struct cuse_init_args *ia = container_of(args, typeof(*ia), ap.args);
+	struct fuse_args_pages *ap = &ia->ap;
 	struct cuse_conn *cc = fc_to_cc(fc), *pos;
-	struct cuse_init_out *arg = req->out.args[0].value;
-	struct page *page = req->pages[0];
+	struct cuse_init_out *arg = &ia->out;
+	struct page *page = ap->pages[0];
 	struct cuse_devinfo devinfo = { };
 	struct device *dev;
 	struct cdev *cdev;
 	dev_t devt;
 	int rc, i;
 
-	if (req->out.h.error ||
-	    arg->major != FUSE_KERNEL_VERSION || arg->minor < 11) {
+	if (error || arg->major != FUSE_KERNEL_VERSION || arg->minor < 11)
 		goto err;
-	}
 
 	fc->minor = arg->minor;
 	fc->max_read = max_t(unsigned, arg->max_read, 4096);
@@ -328,7 +337,7 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 	/* parse init reply */
 	cc->unrestricted_ioctl = arg->flags & CUSE_UNRESTRICTED_IOCTL;
 
-	rc = cuse_parse_devinfo(page_address(page), req->out.args[1].size,
+	rc = cuse_parse_devinfo(page_address(page), ap->args.out_args[1].size,
 				&devinfo);
 	if (rc)
 		goto err;
@@ -395,7 +404,7 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 	dev_set_uevent_suppress(dev, 0);
 	kobject_uevent(&dev->kobj, KOBJ_ADD);
 out:
-	kfree(arg);
+	kfree(ia);
 	__free_page(page);
 	return;
 
@@ -414,55 +423,49 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 static int cuse_send_init(struct cuse_conn *cc)
 {
 	int rc;
-	struct fuse_req *req;
 	struct page *page;
 	struct fuse_conn *fc = &cc->fc;
-	struct cuse_init_in *arg;
-	void *outarg;
+	struct cuse_init_args *ia;
+	struct fuse_args_pages *ap;
 
 	BUILD_BUG_ON(CUSE_INIT_INFO_MAX > PAGE_SIZE);
 
-	req = fuse_get_req_for_background(fc, 1);
-	if (IS_ERR(req)) {
-		rc = PTR_ERR(req);
-		goto err;
-	}
-
 	rc = -ENOMEM;
 	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 	if (!page)
-		goto err_put_req;
+		goto err;
 
-	outarg = kzalloc(sizeof(struct cuse_init_out), GFP_KERNEL);
-	if (!outarg)
+	ia = kzalloc(sizeof(*ia), GFP_KERNEL);
+	if (!ia)
 		goto err_free_page;
 
-	arg = &req->misc.cuse_init_in;
-	arg->major = FUSE_KERNEL_VERSION;
-	arg->minor = FUSE_KERNEL_MINOR_VERSION;
-	arg->flags |= CUSE_UNRESTRICTED_IOCTL;
-	req->in.h.opcode = CUSE_INIT;
-	req->in.numargs = 1;
-	req->in.args[0].size = sizeof(struct cuse_init_in);
-	req->in.args[0].value = arg;
-	req->out.numargs = 2;
-	req->out.args[0].size = sizeof(struct cuse_init_out);
-	req->out.args[0].value = outarg;
-	req->out.args[1].size = CUSE_INIT_INFO_MAX;
-	req->out.argvar = 1;
-	req->out.argpages = 1;
-	req->pages[0] = page;
-	req->page_descs[0].length = req->out.args[1].size;
-	req->num_pages = 1;
-	req->end = cuse_process_init_reply;
-	fuse_request_send_background(fc, req);
-
-	return 0;
-
+	ap = &ia->ap;
+	ia->in.major = FUSE_KERNEL_VERSION;
+	ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
+	ia->in.flags |= CUSE_UNRESTRICTED_IOCTL;
+	ap->args.opcode = CUSE_INIT;
+	ap->args.in_numargs = 1;
+	ap->args.in_args[0].size = sizeof(ia->in);
+	ap->args.in_args[0].value = &ia->in;
+	ap->args.out_numargs = 2;
+	ap->args.out_args[0].size = sizeof(ia->out);
+	ap->args.out_args[0].value = &ia->out;
+	ap->args.out_args[1].size = CUSE_INIT_INFO_MAX;
+	ap->args.out_argvar = 1;
+	ap->args.out_pages = 1;
+	ap->num_pages = 1;
+	ap->pages = &ia->page;
+	ap->descs = &ia->desc;
+	ia->page = page;
+	ia->desc.length = ap->args.out_args[1].size;
+	ap->args.end = cuse_process_init_reply;
+
+	rc = fuse_simple_background(fc, &ap->args, GFP_KERNEL);
+	if (rc) {
+		kfree(ia);
 err_free_page:
-	__free_page(page);
-err_put_req:
-	fuse_put_request(fc, req);
+		__free_page(page);
+	}
 err:
 	return rc;
 }