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>

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 05c3eec298f2e5f6d74df583340923bfce4d8247..af37ae138252acaa8892ce6d598adab10534f9cf 100644 (file)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -34,34 +34,55 @@ static struct fuse_conn *fuse_get_conn(struct file *file)
        return file->private_data;
 }
 
-static void fuse_request_init(struct fuse_req *req)
+static void fuse_request_init(struct fuse_req *req, struct page **pages,
+                             unsigned npages)
 {
        memset(req, 0, sizeof(*req));
+       memset(pages, 0, sizeof(*pages) * npages);
        INIT_LIST_HEAD(&req->list);
        INIT_LIST_HEAD(&req->intr_entry);
        init_waitqueue_head(&req->waitq);
        atomic_set(&req->count, 1);
+       req->pages = pages;
+       req->max_pages = npages;
 }
 
-struct fuse_req *fuse_request_alloc(void)
+static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
 {
-       struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL);
-       if (req)
-               fuse_request_init(req);
+       struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
+       if (req) {
+               struct page **pages;
+
+               if (npages <= FUSE_REQ_INLINE_PAGES)
+                       pages = req->inline_pages;
+               else
+                       pages = kmalloc(sizeof(struct page *) * npages, flags);
+
+               if (!pages) {
+                       kmem_cache_free(fuse_req_cachep, req);
+                       return NULL;
+               }
+
+               fuse_request_init(req, pages, npages);
+       }
        return req;
 }
+
+struct fuse_req *fuse_request_alloc(unsigned npages)
+{
+       return __fuse_request_alloc(npages, GFP_KERNEL);
+}
 EXPORT_SYMBOL_GPL(fuse_request_alloc);
 
-struct fuse_req *fuse_request_alloc_nofs(void)
+struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
 {
-       struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS);
-       if (req)
-               fuse_request_init(req);
-       return req;
+       return __fuse_request_alloc(npages, GFP_NOFS);
 }
 
 void fuse_request_free(struct fuse_req *req)
 {
+       if (req->pages != req->inline_pages)
+               kfree(req->pages);
        kmem_cache_free(fuse_req_cachep, req);
 }
 
@@ -116,7 +137,7 @@ struct fuse_req *fuse_get_req(struct fuse_conn *fc)
        if (!fc->connected)
                goto out;
 
-       req = fuse_request_alloc();
+       req = fuse_request_alloc(FUSE_MAX_PAGES_PER_REQ);
        err = -ENOMEM;
        if (!req)
                goto out;
@@ -165,7 +186,7 @@ static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
        struct fuse_file *ff = file->private_data;
 
        spin_lock(&fc->lock);
-       fuse_request_init(req);
+       fuse_request_init(req, req->pages, req->max_pages);
        BUG_ON(ff->reserved_req);
        ff->reserved_req = req;
        wake_up_all(&fc->reserved_req_waitq);
@@ -192,7 +213,7 @@ struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
 
        atomic_inc(&fc->num_waiting);
        wait_event(fc->blocked_waitq, !fc->blocked);
-       req = fuse_request_alloc();
+       req = fuse_request_alloc(FUSE_MAX_PAGES_PER_REQ);
        if (!req)
                req = get_reserved_req(fc, file);
 

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index f3ab824fa302bcae5909adf5c676c4bbb9417743..2565f635c04f365118d39b34d06b96a09d8c50b3 100644 (file)
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -57,7 +57,7 @@ struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
                return NULL;
 
        ff->fc = fc;
-       ff->reserved_req = fuse_request_alloc();
+       ff->reserved_req = fuse_request_alloc(0);
        if (unlikely(!ff->reserved_req)) {
                kfree(ff);
                return NULL;
@@ -1272,7 +1272,7 @@ static int fuse_writepage_locked(struct page *page)
 
        set_page_writeback(page);
 
-       req = fuse_request_alloc_nofs();
+       req = fuse_request_alloc_nofs(1);
        if (!req)
                goto err;
 

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 5c5055306d3cd9b71badb197f2ded01433b70065..0c5b9310f9302eada8ab80802a2474e72b489a6f 100644 (file)
--- 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

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 6f7d5746bf52dc55a0f74e64b9f4fe57d8c3f39c..9a937f0239e891045ce460235599512573913fde 100644 (file)
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1037,12 +1037,12 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
        /* only now - we want root dentry with NULL ->d_op */
        sb->s_d_op = &fuse_dentry_operations;
 
-       init_req = fuse_request_alloc();
+       init_req = fuse_request_alloc(0);
        if (!init_req)
                goto err_put_root;
 
        if (is_bdev) {
-               fc->destroy_req = fuse_request_alloc();
+               fc->destroy_req = fuse_request_alloc(0);
                if (!fc->destroy_req)
                        goto err_free_init_req;
        }