fuse: convert readdir to simple api

The old fuse_read_fill() helper can be deleted, now that the last user is
gone.

The fuse_io_args struct is moved to fuse_i.h so it can be shared between
readdir/read code.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/file.c

@@ -532,42 +532,6 @@ static int fuse_fsync(struct file *file, loff_t start, loff_t end,
 	return err;
 }
 
-void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
-		    size_t count, int opcode)
-{
-	struct fuse_read_in *inarg = &req->misc.read.in;
-	struct fuse_file *ff = file->private_data;
-
-	inarg->fh = ff->fh;
-	inarg->offset = pos;
-	inarg->size = count;
-	inarg->flags = file->f_flags;
-	req->in.h.opcode = opcode;
-	req->in.h.nodeid = ff->nodeid;
-	req->in.numargs = 1;
-	req->in.args[0].size = sizeof(struct fuse_read_in);
-	req->in.args[0].value = inarg;
-	req->out.argvar = 1;
-	req->out.numargs = 1;
-	req->out.args[0].size = count;
-}
-
-struct fuse_io_args {
-	union {
-		struct {
-			struct fuse_read_in in;
-			u64 attr_ver;
-		} read;
-		struct {
-			struct fuse_write_in in;
-			struct fuse_write_out out;
-		} write;
-	};
-	struct fuse_args_pages ap;
-	struct fuse_io_priv *io;
-	struct fuse_file *ff;
-};
-
 void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
 			 size_t count, int opcode)
 {

fs/fuse/fuse_i.h

@@ -830,11 +830,28 @@ void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 
 struct fuse_forget_link *fuse_alloc_forget(void);
 
-/**
+/*
  * Initialize READ or READDIR request
  */
-void fuse_read_fill(struct fuse_req *req, struct file *file,
-		    loff_t pos, size_t count, int opcode);
+struct fuse_io_args {
+	union {
+		struct {
+			struct fuse_read_in in;
+			u64 attr_ver;
+		} read;
+		struct {
+			struct fuse_write_in in;
+			struct fuse_write_out out;
+		} write;
+	};
+	struct fuse_args_pages ap;
+	struct fuse_io_priv *io;
+	struct fuse_file *ff;
+};
+
+void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
+			 size_t count, int opcode);
+
 
 /**
  * Send OPEN or OPENDIR request

fs/fuse/readdir.c

@@ -316,62 +316,55 @@ static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
 
 static int fuse_readdir_uncached(struct file *file, struct dir_context *ctx)
 {
-	int plus, err;
-	size_t nbytes;
+	int plus;
+	ssize_t res;
 	struct page *page;
 	struct inode *inode = file_inode(file);
 	struct fuse_conn *fc = get_fuse_conn(inode);
-	struct fuse_req *req;
+	struct fuse_io_args ia = {};
+	struct fuse_args_pages *ap = &ia.ap;
+	struct fuse_page_desc desc = { .length = PAGE_SIZE };
 	u64 attr_version = 0;
 	bool locked;
 
-	req = fuse_get_req(fc, 1);
-	if (IS_ERR(req))
-		return PTR_ERR(req);
-
 	page = alloc_page(GFP_KERNEL);
-	if (!page) {
-		fuse_put_request(fc, req);
+	if (!page)
 		return -ENOMEM;
-	}
 
 	plus = fuse_use_readdirplus(inode, ctx);
-	req->out.argpages = 1;
-	req->num_pages = 1;
-	req->pages[0] = page;
-	req->page_descs[0].length = PAGE_SIZE;
+	ap->args.out_pages = 1;
+	ap->num_pages = 1;
+	ap->pages = &page;
+	ap->descs = &desc;
 	if (plus) {
 		attr_version = fuse_get_attr_version(fc);
-		fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
+		fuse_read_args_fill(&ia, file, ctx->pos, PAGE_SIZE,
 				    FUSE_READDIRPLUS);
 	} else {
-		fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
+		fuse_read_args_fill(&ia, file, ctx->pos, PAGE_SIZE,
 				    FUSE_READDIR);
 	}
 	locked = fuse_lock_inode(inode);
-	fuse_request_send(fc, req);
+	res = fuse_simple_request(fc, &ap->args);
 	fuse_unlock_inode(inode, locked);
-	nbytes = req->out.args[0].size;
-	err = req->out.h.error;
-	fuse_put_request(fc, req);
-	if (!err) {
-		if (!nbytes) {
+	if (res >= 0) {
+		if (!res) {
 			struct fuse_file *ff = file->private_data;
 
 			if (ff->open_flags & FOPEN_CACHE_DIR)
 				fuse_readdir_cache_end(file, ctx->pos);
 		} else if (plus) {
-			err = parse_dirplusfile(page_address(page), nbytes,
+			res = parse_dirplusfile(page_address(page), res,
 						file, ctx, attr_version);
 		} else {
-			err = parse_dirfile(page_address(page), nbytes, file,
+			res = parse_dirfile(page_address(page), res, file,
 					    ctx);
 		}
 	}
 
 	__free_page(page);
 	fuse_invalidate_atime(inode);
-	return err;
+	return res;
 }
 
 enum fuse_parse_result {