[PATCH] squashfs: Make SquashFS 4 use the new pcomp crypto interface

[Geert Uytterhoeven]

Modify SquashFS 4 to use the new "pcomp" crypto interface for decompression,
instead of calling the underlying zlib library directly. This simplifies e.g.
the addition of support for hardware decompression and different decompression
algorithms.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@xxxxxxxxxxx>
Cc: Phillip Lougher <phillip@xxxxxxxxxxxxxxxxxxx>
---
 fs/squashfs/Kconfig          |    3 +-
 fs/squashfs/block.c          |   70 ++++++++++++++++++++++++-----------------
 fs/squashfs/squashfs_fs_sb.h |    2 +-
 fs/squashfs/super.c          |   44 +++++++++++++++++++++-----
 4 files changed, 80 insertions(+), 39 deletions(-)

diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index 25a00d1..18e33a6 100644
--- a/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@ -1,7 +1,8 @@
 config SQUASHFS
 	tristate "SquashFS 4.0 - Squashed file system support"
 	depends on BLOCK
-	select ZLIB_INFLATE
+	select CRYPTO
+	select CRYPTO_ZLIB
 	help
 	  Saying Y here includes support for SquashFS 4.0 (a Compressed
 	  Read-Only File System).  Squashfs is a highly compressed read-only
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 2a79603..6196821 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -32,7 +32,8 @@
 #include <linux/mutex.h>
 #include <linux/string.h>
 #include <linux/buffer_head.h>
-#include <linux/zlib.h>
+
+#include <crypto/compress.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
@@ -153,7 +154,9 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 	}
 
 	if (compressed) {
-		int zlib_err = 0, zlib_init = 0;
+		int error = 0, decomp_init = 0;
+		struct comp_request req;
+		unsigned int produced = 0;
 
 		/*
 		 * Uncompress block.
@@ -161,12 +164,13 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 
 		mutex_lock(&msblk->read_data_mutex);
 
-		msblk->stream.avail_out = 0;
-		msblk->stream.avail_in = 0;
+		req.avail_out = 0;
+		req.avail_in = 0;
 
 		bytes = length;
+		length = 0;
 		do {
-			if (msblk->stream.avail_in == 0 && k < b) {
+			if (req.avail_in == 0 && k < b) {
 				avail = min(bytes, msblk->devblksize - offset);
 				bytes -= avail;
 				wait_on_buffer(bh[k]);
@@ -179,45 +183,53 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 					continue;
 				}
 
-				msblk->stream.next_in = bh[k]->b_data + offset;
-				msblk->stream.avail_in = avail;
+				req.next_in = bh[k]->b_data + offset;
+				req.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 (req.avail_out == 0 && page < pages) {
+				req.next_out = buffer[page++];
+				req.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);
+			if (!decomp_init) {
+				error = crypto_decompress_init(msblk->tfm);
+				if (error) {
+					ERROR("crypto_decompress_init "
+						"returned %d, srclength %d\n",
+						error, srclength);
 					goto release_mutex;
 				}
-				zlib_init = 1;
+				decomp_init = 1;
+			}
+
+			produced = req.avail_out;
+			error = crypto_decompress_update(msblk->tfm, &req);
+			if (error) {
+				ERROR("crypto_decompress_update returned %d, "
+					"data probably corrupt\n", error);
+				goto release_mutex;
 			}
+			produced -= req.avail_out;
 
-			zlib_err = zlib_inflate(&msblk->stream, Z_SYNC_FLUSH);
+			length += produced;
 
-			if (msblk->stream.avail_in == 0 && k < b)
+			if (req.avail_in == 0 && k < b)
 				put_bh(bh[k++]);
-		} while (zlib_err == Z_OK);
+		} while (bytes || produced);
 
-		if (zlib_err != Z_STREAM_END) {
-			ERROR("zlib_inflate error, data probably corrupt\n");
+		produced = req.avail_out;
+		error = crypto_decompress_final(msblk->tfm, &req);
+		if (error) {
+			ERROR("crypto_decompress_final returned %d, data "
+				"probably corrupt\n", error);
 			goto release_mutex;
 		}
+		produced -= req.avail_out;
+
+		length += produced;
 
-		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);
 	} else {
 		/*
diff --git a/fs/squashfs/squashfs_fs_sb.h b/fs/squashfs/squashfs_fs_sb.h
index c8c6561..4eae75b 100644
--- a/fs/squashfs/squashfs_fs_sb.h
+++ b/fs/squashfs/squashfs_fs_sb.h
@@ -64,7 +64,7 @@ struct squashfs_sb_info {
 	struct mutex		read_data_mutex;
 	struct mutex		meta_index_mutex;
 	struct meta_index	*meta_index;
-	z_stream		stream;
+	struct crypto_pcomp	*tfm;
 	__le64			*inode_lookup_table;
 	u64			inode_table;
 	u64			directory_table;
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 681ec0d..2b63f54 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -37,11 +37,19 @@
 #include <linux/zlib.h>
 #include <linux/magic.h>
 
+#include <crypto/compress.h>
+
+#include <net/netlink.h>
+
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
 #include "squashfs_fs_i.h"
 #include "squashfs.h"
 
+
+#define SQUASHFS_CRYPTO_ALG	"zlib"
+
+
 static struct file_system_type squashfs_fs_type;
 static struct super_operations squashfs_super_ops;
 
@@ -75,6 +83,16 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 	unsigned short flags;
 	unsigned int fragments;
 	u64 lookup_table_start;
+	struct {
+		struct nlattr nla;
+		int val;
+	} params = {
+		.nla = {
+			.nla_len	= nla_attr_size(sizeof(int)),
+			.nla_type	= ZLIB_DECOMP_WINDOWBITS,
+		},
+		.val			= DEF_WBITS,
+	};
 	int err;
 
 	TRACE("Entered squashfs_fill_superblock\n");
@@ -86,16 +104,25 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 	}
 	msblk = sb->s_fs_info;
 
-	msblk->stream.workspace = kmalloc(zlib_inflate_workspacesize(),
-		GFP_KERNEL);
-	if (msblk->stream.workspace == NULL) {
-		ERROR("Failed to allocate zlib workspace\n");
+	msblk->tfm = crypto_alloc_pcomp(SQUASHFS_CRYPTO_ALG, 0,
+					CRYPTO_ALG_ASYNC);
+	if (IS_ERR(msblk->tfm)) {
+		ERROR("Failed to load %s crypto module\n",
+		      SQUASHFS_CRYPTO_ALG);
+		err = PTR_ERR(msblk->tfm);
+		goto failed_pcomp;
+	}
+
+	err = crypto_decompress_setup(msblk->tfm, &params, sizeof(params));
+	if (err) {
+		ERROR("Failed to set up decompression parameters\n");
 		goto failure;
 	}
 
 	sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
 	if (sblk == NULL) {
 		ERROR("Failed to allocate squashfs_super_block\n");
+		err = -ENOMEM;
 		goto failure;
 	}
 
@@ -284,17 +311,18 @@ failed_mount:
 	kfree(msblk->inode_lookup_table);
 	kfree(msblk->fragment_index);
 	kfree(msblk->id_table);
-	kfree(msblk->stream.workspace);
+	crypto_free_pcomp(msblk->tfm);
 	kfree(sb->s_fs_info);
 	sb->s_fs_info = NULL;
 	kfree(sblk);
 	return err;
 
 failure:
-	kfree(msblk->stream.workspace);
+	crypto_free_pcomp(msblk->tfm);
+failed_pcomp:
 	kfree(sb->s_fs_info);
 	sb->s_fs_info = NULL;
-	return -ENOMEM;
+	return err;
 }
 
 
@@ -333,7 +361,7 @@ static void squashfs_put_super(struct super_block *sb)
 		kfree(sbi->id_table);
 		kfree(sbi->fragment_index);
 		kfree(sbi->meta_index);
-		kfree(sbi->stream.workspace);
+		crypto_free_pcomp(sbi->tfm);
 		kfree(sb->s_fs_info);
 		sb->s_fs_info = NULL;
 	}
-- 
1.6.0.4


With kind regards,

Geert Uytterhoeven
Software Architect

Sony Techsoft Centre Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium

Phone:    +32 (0)2 700 8453
Fax:      +32 (0)2 700 8622
E-mail:   Geert.Uytterhoeven@xxxxxxxxxxx
Internet: http://www.sony-europe.com/

A division of Sony Europe (Belgium) N.V.
VAT BE 0413.825.160 · RPR Brussels
Fortis · BIC GEBABEBB · IBAN BE41293037680010
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