fuse: convert ioctl to simple api

fuse_simple_request() is converted to return length of last (instead of
single) out arg, since FUSE_IOCTL_OUT has two out args, the second of which
is variable length.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/dev.c

@@ -590,8 +590,8 @@ ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
 	__fuse_request_send(fc, req);
 	ret = req->out.h.error;
 	if (!ret && args->out_argvar) {
-		BUG_ON(args->out_numargs != 1);
-		ret = req->out.args[0].size;
+		BUG_ON(args->out_numargs == 0);
+		ret = req->out.args[args->out_numargs - 1].size;
 	}
 	fuse_put_request(fc, req);
 

fs/fuse/file.c

@@ -1267,14 +1267,14 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	return written ? written : err;
 }
 
-static inline void fuse_page_descs_length_init(struct fuse_req *req,
-		unsigned index, unsigned nr_pages)
+static inline void fuse_page_descs_length_init(struct fuse_page_desc *descs,
+					       unsigned int index,
+					       unsigned int nr_pages)
 {
 	int i;
 
 	for (i = index; i < index + nr_pages; i++)
-		req->page_descs[i].length = PAGE_SIZE -
-			req->page_descs[i].offset;
+		descs[i].length = PAGE_SIZE - descs[i].offset;
 }
 
 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
@@ -1326,7 +1326,8 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
 		npages = (ret + PAGE_SIZE - 1) / PAGE_SIZE;
 
 		req->page_descs[req->num_pages].offset = start;
-		fuse_page_descs_length_init(req, req->num_pages, npages);
+		fuse_page_descs_length_init(req->page_descs, req->num_pages,
+					    npages);
 
 		req->num_pages += npages;
 		req->page_descs[req->num_pages - 1].length -=
@@ -2582,14 +2583,14 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 		.flags = flags
 	};
 	struct fuse_ioctl_out outarg;
-	struct fuse_req *req = NULL;
-	struct page **pages = NULL;
 	struct iovec *iov_page = NULL;
 	struct iovec *in_iov = NULL, *out_iov = NULL;
-	unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
-	size_t in_size, out_size, transferred, c;
+	unsigned int in_iovs = 0, out_iovs = 0, max_pages;
+	size_t in_size, out_size, c;
+	ssize_t transferred;
 	int err, i;
 	struct iov_iter ii;
+	struct fuse_args_pages ap = {};
 
 #if BITS_PER_LONG == 32
 	inarg.flags |= FUSE_IOCTL_32BIT;
@@ -2607,11 +2608,13 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 	BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
 
 	err = -ENOMEM;
-	pages = kcalloc(fc->max_pages, sizeof(pages[0]), GFP_KERNEL);
+	ap.pages = fuse_pages_alloc(fc->max_pages, GFP_KERNEL, &ap.descs);
 	iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
-	if (!pages || !iov_page)
+	if (!ap.pages || !iov_page)
 		goto out;
 
+	fuse_page_descs_length_init(ap.descs, 0, fc->max_pages);
+
 	/*
 	 * If restricted, initialize IO parameters as encoded in @cmd.
 	 * RETRY from server is not allowed.
@@ -2648,56 +2651,44 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 	err = -ENOMEM;
 	if (max_pages > fc->max_pages)
 		goto out;
-	while (num_pages < max_pages) {
-		pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
-		if (!pages[num_pages])
+	while (ap.num_pages < max_pages) {
+		ap.pages[ap.num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
+		if (!ap.pages[ap.num_pages])
 			goto out;
-		num_pages++;
+		ap.num_pages++;
 	}
 
-	req = fuse_get_req(fc, num_pages);
-	if (IS_ERR(req)) {
-		err = PTR_ERR(req);
-		req = NULL;
-		goto out;
-	}
-	memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
-	req->num_pages = num_pages;
-	fuse_page_descs_length_init(req, 0, req->num_pages);
 
 	/* okay, let's send it to the client */
-	req->in.h.opcode = FUSE_IOCTL;
-	req->in.h.nodeid = ff->nodeid;
-	req->in.numargs = 1;
-	req->in.args[0].size = sizeof(inarg);
-	req->in.args[0].value = &inarg;
+	ap.args.opcode = FUSE_IOCTL;
+	ap.args.nodeid = ff->nodeid;
+	ap.args.in_numargs = 1;
+	ap.args.in_args[0].size = sizeof(inarg);
+	ap.args.in_args[0].value = &inarg;
 	if (in_size) {
-		req->in.numargs++;
-		req->in.args[1].size = in_size;
-		req->in.argpages = 1;
+		ap.args.in_numargs++;
+		ap.args.in_args[1].size = in_size;
+		ap.args.in_pages = true;
 
 		err = -EFAULT;
 		iov_iter_init(&ii, WRITE, in_iov, in_iovs, in_size);
-		for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= num_pages); i++) {
-			c = copy_page_from_iter(pages[i], 0, PAGE_SIZE, &ii);
+		for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
+			c = copy_page_from_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
 			if (c != PAGE_SIZE && iov_iter_count(&ii))
 				goto out;
 		}
 	}
 
-	req->out.numargs = 2;
-	req->out.args[0].size = sizeof(outarg);
-	req->out.args[0].value = &outarg;
-	req->out.args[1].size = out_size;
-	req->out.argpages = 1;
-	req->out.argvar = 1;
+	ap.args.out_numargs = 2;
+	ap.args.out_args[0].size = sizeof(outarg);
+	ap.args.out_args[0].value = &outarg;
+	ap.args.out_args[1].size = out_size;
+	ap.args.out_pages = true;
+	ap.args.out_argvar = true;
 
-	fuse_request_send(fc, req);
-	err = req->out.h.error;
-	transferred = req->out.args[1].size;
-	fuse_put_request(fc, req);
-	req = NULL;
-	if (err)
+	transferred = fuse_simple_request(fc, &ap.args);
+	err = transferred;
+	if (transferred < 0)
 		goto out;
 
 	/* did it ask for retry? */
@@ -2722,7 +2713,7 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 		    in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
 			goto out;
 
-		vaddr = kmap_atomic(pages[0]);
+		vaddr = kmap_atomic(ap.pages[0]);
 		err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
 					    transferred, in_iovs + out_iovs,
 					    (flags & FUSE_IOCTL_COMPAT) != 0);
@@ -2750,19 +2741,17 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 
 	err = -EFAULT;
 	iov_iter_init(&ii, READ, out_iov, out_iovs, transferred);
-	for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= num_pages); i++) {
-		c = copy_page_to_iter(pages[i], 0, PAGE_SIZE, &ii);
+	for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
+		c = copy_page_to_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
 		if (c != PAGE_SIZE && iov_iter_count(&ii))
 			goto out;
 	}
 	err = 0;
  out:
-	if (req)
-		fuse_put_request(fc, req);
 	free_page((unsigned long) iov_page);
-	while (num_pages)
-		__free_page(pages[--num_pages]);
-	kfree(pages);
+	while (ap.num_pages)
+		__free_page(ap.pages[--ap.num_pages]);
+	kfree(ap.pages);
 
 	return err ? err : outarg.result;
 }