1 files changed, 114 insertions, 61 deletions

diff --git a/fs/squashfs/page_actor.c b/fs/squashfs/page_actor.c
index 5a1c11f56441..53863508e400 100644
--- a/fs/squashfs/page_actor.c
+++ b/fs/squashfs/page_actor.c
@@ -9,39 +9,11 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
+#include <linux/buffer_head.h>
 #include "page_actor.h"
 
-/*
- * This file contains implementations of page_actor for decompressing into
- * an intermediate buffer, and for decompressing directly into the
- * page cache.
- *
- * Calling code should avoid sleeping between calls to squashfs_first_page()
- * and squashfs_finish_page().
- */
-
-/* Implementation of page_actor for decompressing into intermediate buffer */
-static void *cache_first_page(struct squashfs_page_actor *actor)
-{
-	actor->next_page = 1;
-	return actor->buffer[0];
-}
-
-static void *cache_next_page(struct squashfs_page_actor *actor)
-{
-	if (actor->next_page == actor->pages)
-		return NULL;
-
-	return actor->buffer[actor->next_page++];
-}
-
-static void cache_finish_page(struct squashfs_page_actor *actor)
-{
-	/* empty */
-}
-
-struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
-	int pages, int length)
+struct squashfs_page_actor *squashfs_page_actor_init(struct page **page,
+	int pages, int length, void (*release_pages)(struct page **, int, int))
 {
 	struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
 
@@ -49,52 +21,133 @@ struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
 		return NULL;
 
 	actor->length = length ? : pages * PAGE_CACHE_SIZE;
-	actor->buffer = buffer;
+	actor->page = page;
 	actor->pages = pages;
 	actor->next_page = 0;
-	actor->squashfs_first_page = cache_first_page;
-	actor->squashfs_next_page = cache_next_page;
-	actor->squashfs_finish_page = cache_finish_page;
+	actor->pageaddr = NULL;
+	actor->release_pages = release_pages;
 	return actor;
 }
 
-/* Implementation of page_actor for decompressing directly into page cache. */
-static void *direct_first_page(struct squashfs_page_actor *actor)
+void squashfs_page_actor_free(struct squashfs_page_actor *actor, int error)
+{
+	if (!actor)
+		return;
+
+	if (actor->release_pages)
+		actor->release_pages(actor->page, actor->pages, error);
+	kfree(actor);
+}
+
+void squashfs_actor_to_buf(struct squashfs_page_actor *actor, void *buf,
+	int length)
 {
-	actor->next_page = 1;
-	return actor->pageaddr = kmap_atomic(actor->page[0]);
+	void *pageaddr;
+	int pos = 0, avail, i;
+
+	for (i = 0; i < actor->pages && pos < length; ++i) {
+		avail = min_t(int, length - pos, PAGE_CACHE_SIZE);
+		if (actor->page[i]) {
+			pageaddr = kmap_atomic(actor->page[i]);
+			memcpy(buf + pos, pageaddr, avail);
+			kunmap_atomic(pageaddr);
+		}
+		pos += avail;
+	}
 }
 
-static void *direct_next_page(struct squashfs_page_actor *actor)
+void squashfs_buf_to_actor(void *buf, struct squashfs_page_actor *actor,
+	int length)
 {
-	if (actor->pageaddr)
-		kunmap_atomic(actor->pageaddr);
+	void *pageaddr;
+	int pos = 0, avail, i;
+
+	for (i = 0; i < actor->pages && pos < length; ++i) {
+		avail = min_t(int, length - pos, PAGE_CACHE_SIZE);
+		if (actor->page[i]) {
+			pageaddr = kmap_atomic(actor->page[i]);
+			memcpy(pageaddr, buf + pos, avail);
+			kunmap_atomic(pageaddr);
+		}
+		pos += avail;
+	}
+}
 
-	return actor->pageaddr = actor->next_page == actor->pages ? NULL :
-		kmap_atomic(actor->page[actor->next_page++]);
+void squashfs_bh_to_actor(struct buffer_head **bh, int nr_buffers,
+	struct squashfs_page_actor *actor, int offset, int length, int blksz)
+{
+	void *kaddr = NULL;
+	int bytes = 0, pgoff = 0, b = 0, p = 0, avail, i;
+
+	while (bytes < length) {
+		if (actor->page[p]) {
+			kaddr = kmap_atomic(actor->page[p]);
+			while (pgoff < PAGE_CACHE_SIZE && bytes < length) {
+				avail = min_t(int, blksz - offset,
+						PAGE_CACHE_SIZE - pgoff);
+				memcpy(kaddr + pgoff, bh[b]->b_data + offset,
+				       avail);
+				pgoff += avail;
+				bytes += avail;
+				offset = (offset + avail) % blksz;
+				if (!offset) {
+					put_bh(bh[b]);
+					++b;
+				}
+			}
+			kunmap_atomic(kaddr);
+			pgoff = 0;
+		} else {
+			for (i = 0; i < PAGE_CACHE_SIZE / blksz; ++i) {
+				if (bh[b])
+					put_bh(bh[b]);
+				++b;
+			}
+			bytes += PAGE_CACHE_SIZE;
+		}
+		++p;
+	}
 }
 
-static void direct_finish_page(struct squashfs_page_actor *actor)
+void squashfs_bh_to_buf(struct buffer_head **bh, int nr_buffers, void *buf,
+	int offset, int length, int blksz)
 {
-	if (actor->pageaddr)
-		kunmap_atomic(actor->pageaddr);
+	int i, avail, bytes = 0;
+
+	for (i = 0; i < nr_buffers && bytes < length; ++i) {
+		avail = min_t(int, length - bytes, blksz - offset);
+		if (bh[i]) {
+			memcpy(buf + bytes, bh[i]->b_data + offset, avail);
+			put_bh(bh[i]);
+		}
+		bytes += avail;
+		offset = 0;
+	}
 }
 
-struct squashfs_page_actor *squashfs_page_actor_init_special(struct page **page,
-	int pages, int length)
+void free_page_array(struct page **page, int nr_pages)
 {
-	struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
+	int i;
 
-	if (actor == NULL)
-		return NULL;
+	for (i = 0; i < nr_pages; ++i)
+		__free_page(page[i]);
+	kfree(page);
+}
 
-	actor->length = length ? : pages * PAGE_CACHE_SIZE;
-	actor->page = page;
-	actor->pages = pages;
-	actor->next_page = 0;
-	actor->pageaddr = NULL;
-	actor->squashfs_first_page = direct_first_page;
-	actor->squashfs_next_page = direct_next_page;
-	actor->squashfs_finish_page = direct_finish_page;
-	return actor;
+struct page **alloc_page_array(int nr_pages, int gfp_mask)
+{
+	int i;
+	struct page **page;
+
+	page = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
+	if (!page)
+		return NULL;
+	for (i = 0; i < nr_pages; ++i) {
+		page[i] = alloc_page(gfp_mask);
+		if (!page[i]) {
+			free_page_array(page, i);
+			return NULL;
+		}
+	}
+	return page;
 }