fuse: general infrastructure for pages[] of variable size

The patch removes inline array of FUSE_MAX_PAGES_PER_REQ page pointers from
fuse_req. Instead of that, req->pages may now point either to small inline
array or to an array allocated dynamically.

This essentially means that all callers of fuse_request_alloc[_nofs] should
pass the number of pages needed explicitly.

The patch doesn't make any logic changes.

Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 12 insertions, 3 deletions

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 5c5055306d3c..0c5b9310f930 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -44,6 +44,9 @@
     doing the mount will be allowed to access the filesystem */
 #define FUSE_ALLOW_OTHER         (1 << 1)
 
+/** Number of page pointers embedded in fuse_req */
+#define FUSE_REQ_INLINE_PAGES 1
+
 /** List of active connections */
 extern struct list_head fuse_conn_list;
 
@@ -291,7 +294,13 @@ struct fuse_req {
         } misc;
 
         /** page vector */
-        struct page *pages[FUSE_MAX_PAGES_PER_REQ];
+        struct page **pages;
+
+        /** size of the 'pages' array */
+        unsigned max_pages;
+
+        /** inline page vector */
+        struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
 
         /** number of pages in vector */
         unsigned num_pages;
@@ -664,9 +673,9 @@ void fuse_ctl_cleanup(void);
 /**
  * Allocate a request
  */
-struct fuse_req *fuse_request_alloc(void);
+struct fuse_req *fuse_request_alloc(unsigned npages);
 
-struct fuse_req *fuse_request_alloc_nofs(void);
+struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
 
 /**
  * Free a request