Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  mm: export generic_pipe_buf_*() to modules
  fuse: support splice() reading from fuse device
  fuse: allow splice to move pages
  mm: export remove_from_page_cache() to modules
  mm: export lru_cache_add_*() to modules
  fuse: support splice() writing to fuse device
  fuse: get page reference for readpages
  fuse: use get_user_pages_fast()
  fuse: remove unneeded variable

fs/fuse/file.c

@@ -516,17 +516,26 @@ static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 	int i;
 	size_t count = req->misc.read.in.size;
 	size_t num_read = req->out.args[0].size;
-	struct inode *inode = req->pages[0]->mapping->host;
+	struct address_space *mapping = NULL;
 
-	/*
-	 * Short read means EOF.  If file size is larger, truncate it
-	 */
-	if (!req->out.h.error && num_read < count) {
-		loff_t pos = page_offset(req->pages[0]) + num_read;
-		fuse_read_update_size(inode, pos, req->misc.read.attr_ver);
-	}
+	for (i = 0; mapping == NULL && i < req->num_pages; i++)
+		mapping = req->pages[i]->mapping;
 
-	fuse_invalidate_attr(inode); /* atime changed */
+	if (mapping) {
+		struct inode *inode = mapping->host;
+
+		/*
+		 * Short read means EOF. If file size is larger, truncate it
+		 */
+		if (!req->out.h.error && num_read < count) {
+			loff_t pos;
+
+			pos = page_offset(req->pages[0]) + num_read;
+			fuse_read_update_size(inode, pos,
+					      req->misc.read.attr_ver);
+		}
+		fuse_invalidate_attr(inode); /* atime changed */
+	}
 
 	for (i = 0; i < req->num_pages; i++) {
 		struct page *page = req->pages[i];
@@ -535,6 +544,7 @@ static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 		else
 			SetPageError(page);
 		unlock_page(page);
+		page_cache_release(page);
 	}
 	if (req->ff)
 		fuse_file_put(req->ff);
@@ -549,6 +559,7 @@ static void fuse_send_readpages(struct fuse_req *req, struct file *file)
 
 	req->out.argpages = 1;
 	req->out.page_zeroing = 1;
+	req->out.page_replace = 1;
 	fuse_read_fill(req, file, pos, count, FUSE_READ);
 	req->misc.read.attr_ver = fuse_get_attr_version(fc);
 	if (fc->async_read) {
@@ -588,6 +599,7 @@ static int fuse_readpages_fill(void *_data, struct page *page)
 			return PTR_ERR(req);
 		}
 	}
+	page_cache_get(page);
 	req->pages[req->num_pages] = page;
 	req->num_pages++;
 	return 0;
@@ -993,10 +1005,7 @@ static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
 	nbytes = min_t(size_t, nbytes, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
 	npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ);
-	down_read(&current->mm->mmap_sem);
-	npages = get_user_pages(current, current->mm, user_addr, npages, !write,
-				0, req->pages, NULL);
-	up_read(&current->mm->mmap_sem);
+	npages = get_user_pages_fast(user_addr, npages, !write, req->pages);
 	if (npages < 0)
 		return npages;
 
@@ -1579,9 +1588,9 @@ static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
 	while (iov_iter_count(&ii)) {
 		struct page *page = pages[page_idx++];
 		size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
-		void *kaddr, *map;
+		void *kaddr;
 
-		kaddr = map = kmap(page);
+		kaddr = kmap(page);
 
 		while (todo) {
 			char __user *uaddr = ii.iov->iov_base + ii.iov_offset;

fs/fuse/fuse_i.h

@@ -177,6 +177,9 @@ struct fuse_out {
 	/** Zero partially or not copied pages */
 	unsigned page_zeroing:1;
 
+	/** Pages may be replaced with new ones */
+	unsigned page_replace:1;
+
 	/** Number or arguments */
 	unsigned numargs;
 

fs/pipe.c

@@ -230,6 +230,7 @@ void *generic_pipe_buf_map(struct pipe_inode_info *pipe,
 
 	return kmap(buf->page);
 }
+EXPORT_SYMBOL(generic_pipe_buf_map);
 
 /**
  * generic_pipe_buf_unmap - unmap a previously mapped pipe buffer
@@ -249,6 +250,7 @@ void generic_pipe_buf_unmap(struct pipe_inode_info *pipe,
 	} else
 		kunmap(buf->page);
 }
+EXPORT_SYMBOL(generic_pipe_buf_unmap);
 
 /**
  * generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer
@@ -279,6 +281,7 @@ int generic_pipe_buf_steal(struct pipe_inode_info *pipe,
 
 	return 1;
 }
+EXPORT_SYMBOL(generic_pipe_buf_steal);
 
 /**
  * generic_pipe_buf_get - get a reference to a &struct pipe_buffer
@@ -294,6 +297,7 @@ void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
 {
 	page_cache_get(buf->page);
 }
+EXPORT_SYMBOL(generic_pipe_buf_get);
 
 /**
  * generic_pipe_buf_confirm - verify contents of the pipe buffer
@@ -309,6 +313,7 @@ int generic_pipe_buf_confirm(struct pipe_inode_info *info,
 {
 	return 0;
 }
+EXPORT_SYMBOL(generic_pipe_buf_confirm);
 
 /**
  * generic_pipe_buf_release - put a reference to a &struct pipe_buffer
@@ -323,6 +328,7 @@ void generic_pipe_buf_release(struct pipe_inode_info *pipe,
 {
 	page_cache_release(buf->page);
 }
+EXPORT_SYMBOL(generic_pipe_buf_release);
 
 static const struct pipe_buf_operations anon_pipe_buf_ops = {
 	.can_merge = 1,

include/linux/fuse.h

@@ -34,6 +34,9 @@
  * 7.13
  *  - make max number of background requests and congestion threshold
  *    tunables
+ *
+ * 7.14
+ *  - add splice support to fuse device
  */
 
 #ifndef _LINUX_FUSE_H
@@ -65,7 +68,7 @@
 #define FUSE_KERNEL_VERSION 7
 
 /** Minor version number of this interface */
-#define FUSE_KERNEL_MINOR_VERSION 13
+#define FUSE_KERNEL_MINOR_VERSION 14
 
 /** The node ID of the root inode */
 #define FUSE_ROOT_ID 1

mm/filemap.c

@@ -151,6 +151,7 @@ void remove_from_page_cache(struct page *page)
 	spin_unlock_irq(&mapping->tree_lock);
 	mem_cgroup_uncharge_cache_page(page);
 }
+EXPORT_SYMBOL(remove_from_page_cache);
 
 static int sync_page(void *word)
 {

mm/swap.c

@@ -224,6 +224,7 @@ void __lru_cache_add(struct page *page, enum lru_list lru)
 		____pagevec_lru_add(pvec, lru);
 	put_cpu_var(lru_add_pvecs);
 }
+EXPORT_SYMBOL(__lru_cache_add);
 
 /**
  * lru_cache_add_lru - add a page to a page list