Squashfs: move zlib decompression wrapper code into a separate file

Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>

fs/squashfs/Makefile

@@ -4,4 +4,4 @@
 
 obj-$(CONFIG_SQUASHFS) += squashfs.o
 squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
-squashfs-y += namei.o super.o symlink.o
+squashfs-y += namei.o super.o symlink.o zlib_wrapper.o

fs/squashfs/block.c

@@ -29,7 +29,6 @@
 #include <linux/fs.h>
 #include <linux/vfs.h>
 #include <linux/slab.h>
-#include <linux/mutex.h>
 #include <linux/string.h>
 #include <linux/buffer_head.h>
 #include <linux/zlib.h>
@@ -153,72 +152,10 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 	}
 
 	if (compressed) {
-		int zlib_err = 0, zlib_init = 0;
-
-		/*
-		 * Uncompress block.
-		 */
-
-		mutex_lock(&msblk->read_data_mutex);
-
-		msblk->stream.avail_out = 0;
-		msblk->stream.avail_in = 0;
-
-		bytes = length;
-		do {
-			if (msblk->stream.avail_in == 0 && k < b) {
-				avail = min(bytes, msblk->devblksize - offset);
-				bytes -= avail;
-				wait_on_buffer(bh[k]);
-				if (!buffer_uptodate(bh[k]))
-					goto release_mutex;
-
-				if (avail == 0) {
-					offset = 0;
-					put_bh(bh[k++]);
-					continue;
-				}
-
-				msblk->stream.next_in = bh[k]->b_data + offset;
-				msblk->stream.avail_in = avail;
-				offset = 0;
-			}
-
-			if (msblk->stream.avail_out == 0 && page < pages) {
-				msblk->stream.next_out = buffer[page++];
-				msblk->stream.avail_out = PAGE_CACHE_SIZE;
-			}
-
-			if (!zlib_init) {
-				zlib_err = zlib_inflateInit(&msblk->stream);
-				if (zlib_err != Z_OK) {
-					ERROR("zlib_inflateInit returned"
-						" unexpected result 0x%x,"
-						" srclength %d\n", zlib_err,
-						srclength);
-					goto release_mutex;
-				}
-				zlib_init = 1;
-			}
-
-			zlib_err = zlib_inflate(&msblk->stream, Z_SYNC_FLUSH);
-
-			if (msblk->stream.avail_in == 0 && k < b)
-				put_bh(bh[k++]);
-		} while (zlib_err == Z_OK);
-
-		if (zlib_err != Z_STREAM_END) {
-			ERROR("zlib_inflate error, data probably corrupt\n");
-			goto release_mutex;
-		}
-
-		zlib_err = zlib_inflateEnd(&msblk->stream);
-		if (zlib_err != Z_OK) {
-			ERROR("zlib_inflate error, data probably corrupt\n");
-			goto release_mutex;
-		}
-		length = msblk->stream.total_out;
-		mutex_unlock(&msblk->read_data_mutex);
+		length = squashfs_zlib_uncompress(msblk, buffer, bh, b, offset,
+			 length, srclength, pages);
+		if (length < 0)
+			goto read_failure;
 	} else {
 		/*
 		 * Block is uncompressed.
@@ -255,9 +192,6 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 	kfree(bh);
 	return length;
 
-release_mutex:
-	mutex_unlock(&msblk->read_data_mutex);
-
 block_release:
 	for (; k < b; k++)
 		put_bh(bh[k]);

fs/squashfs/squashfs.h

@@ -70,6 +70,10 @@ extern struct inode *squashfs_iget(struct super_block *, long long,
 				unsigned int);
 extern int squashfs_read_inode(struct inode *, long long);
 
+/* zlib_wrapper.c */
+extern int squashfs_zlib_uncompress(struct squashfs_sb_info *, void **,
+				struct buffer_head **, int, int, int, int, int);
+
 /*
  * Inodes and files operations
  */

fs/squashfs/zlib_wrapper.c

@@ -0,0 +1,109 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ * Phillip Lougher <phillip@lougher.demon.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * zlib_wrapper.c
+ */
+
+
+#include <linux/mutex.h>
+#include <linux/buffer_head.h>
+#include <linux/zlib.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+
+int squashfs_zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
+	struct buffer_head **bh, int b, int offset, int length, int srclength,
+	int pages)
+{
+	int zlib_err = 0, zlib_init = 0;
+	int avail, bytes, k = 0, page = 0;
+
+	mutex_lock(&msblk->read_data_mutex);
+
+	msblk->stream.avail_out = 0;
+	msblk->stream.avail_in = 0;
+
+	bytes = length;
+	do {
+		if (msblk->stream.avail_in == 0 && k < b) {
+			avail = min(bytes, msblk->devblksize - offset);
+			bytes -= avail;
+			wait_on_buffer(bh[k]);
+			if (!buffer_uptodate(bh[k]))
+				goto release_mutex;
+
+			if (avail == 0) {
+				offset = 0;
+				put_bh(bh[k++]);
+				continue;
+			}
+
+			msblk->stream.next_in = bh[k]->b_data + offset;
+			msblk->stream.avail_in = avail;
+			offset = 0;
+		}
+
+		if (msblk->stream.avail_out == 0 && page < pages) {
+			msblk->stream.next_out = buffer[page++];
+			msblk->stream.avail_out = PAGE_CACHE_SIZE;
+		}
+
+		if (!zlib_init) {
+			zlib_err = zlib_inflateInit(&msblk->stream);
+			if (zlib_err != Z_OK) {
+				ERROR("zlib_inflateInit returned unexpected "
+					"result 0x%x, srclength %d\n",
+					zlib_err, srclength);
+				goto release_mutex;
+			}
+			zlib_init = 1;
+		}
+
+		zlib_err = zlib_inflate(&msblk->stream, Z_SYNC_FLUSH);
+
+		if (msblk->stream.avail_in == 0 && k < b)
+			put_bh(bh[k++]);
+	} while (zlib_err == Z_OK);
+
+	if (zlib_err != Z_STREAM_END) {
+		ERROR("zlib_inflate error, data probably corrupt\n");
+		goto release_mutex;
+	}
+
+	zlib_err = zlib_inflateEnd(&msblk->stream);
+	if (zlib_err != Z_OK) {
+		ERROR("zlib_inflate error, data probably corrupt\n");
+		goto release_mutex;
+	}
+
+	mutex_unlock(&msblk->read_data_mutex);
+	return msblk->stream.total_out;
+
+release_mutex:
+	mutex_unlock(&msblk->read_data_mutex);
+
+	for (; k < b; k++)
+		put_bh(bh[k]);
+
+	return -EIO;
+}