From 6050a34f2e3ed135fc83a659d38fe9d099b3ea7b Mon Sep 17 00:00:00 2001 From: Phillip Lougher Date: Wed, 13 Nov 2013 02:56:26 +0000 Subject: Squashfs: Refactor decompressor interface and code The decompressor interface and code was written from the point of view of single-threaded operation. In doing so it mixed a lot of single-threaded implementation specific aspects into the decompressor code and elsewhere which makes it difficult to seamlessly support multiple different decompressor implementations. This patch does the following: 1. It removes compressor_options parsing from the decompressor init() function. This allows the decompressor init() function to be dynamically called to instantiate multiple decompressors, without the compressor options needing to be read and parsed each time. 2. It moves threading and all sleeping operations out of the decompressors. In doing so, it makes the decompressors non-blocking wrappers which only deal with interfacing with the decompressor implementation. 3. It splits decompressor.[ch] into decompressor generic functions in decompressor.[ch], and moves the single threaded decompressor implementation into decompressor_single.c. The result of this patch is Squashfs should now be able to support multiple decompressors by adding new decompressor_xxx.c files with specialised implementations of the functions in decompressor_single.c Signed-off-by: Phillip Lougher Reviewed-by: Minchan Kim Change-Id: I79eafe0ea0f9f79f90a94efef083cff452f731e5 --- fs/squashfs/decompressor.c | 47 +++++++++++++++++++++++++++++++--------------- 1 file changed, 32 insertions(+), 15 deletions(-) (limited to 'fs/squashfs/decompressor.c') diff --git a/fs/squashfs/decompressor.c b/fs/squashfs/decompressor.c index 3f6271d86..234291f79 100644 --- a/fs/squashfs/decompressor.c +++ b/fs/squashfs/decompressor.c @@ -37,29 +37,29 @@ */ static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = { - NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0 + NULL, NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0 }; #ifndef CONFIG_SQUASHFS_LZO static const struct squashfs_decompressor squashfs_lzo_comp_ops = { - NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0 + NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0 }; #endif #ifndef CONFIG_SQUASHFS_XZ static const struct squashfs_decompressor squashfs_xz_comp_ops = { - NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0 + NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0 }; #endif #ifndef CONFIG_SQUASHFS_ZLIB static const struct squashfs_decompressor squashfs_zlib_comp_ops = { - NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0 + NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0 }; #endif static const struct squashfs_decompressor squashfs_unknown_comp_ops = { - NULL, NULL, NULL, 0, "unknown", 0 + NULL, NULL, NULL, NULL, 0, "unknown", 0 }; static const struct squashfs_decompressor *decompressor[] = { @@ -83,10 +83,10 @@ const struct squashfs_decompressor *squashfs_lookup_decompressor(int id) } -void *squashfs_decompressor_init(struct super_block *sb, unsigned short flags) +static void *get_comp_opts(struct super_block *sb, unsigned short flags) { struct squashfs_sb_info *msblk = sb->s_fs_info; - void *strm, *buffer = NULL; + void *buffer = NULL, *comp_opts; int length = 0; /* @@ -94,23 +94,40 @@ void *squashfs_decompressor_init(struct super_block *sb, unsigned short flags) */ if (SQUASHFS_COMP_OPTS(flags)) { buffer = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL); - if (buffer == NULL) - return ERR_PTR(-ENOMEM); + if (buffer == NULL) { + comp_opts = ERR_PTR(-ENOMEM); + goto out; + } length = squashfs_read_data(sb, &buffer, sizeof(struct squashfs_super_block), 0, NULL, - PAGE_CACHE_SIZE, 1); + PAGE_CACHE_SIZE, 1); if (length < 0) { - strm = ERR_PTR(length); - goto finished; + comp_opts = ERR_PTR(length); + goto out; } } - strm = msblk->decompressor->init(msblk, buffer, length); + comp_opts = squashfs_comp_opts(msblk, buffer, length); -finished: +out: kfree(buffer); + return comp_opts; +} + + +void *squashfs_decompressor_setup(struct super_block *sb, unsigned short flags) +{ + struct squashfs_sb_info *msblk = sb->s_fs_info; + void *stream, *comp_opts = get_comp_opts(sb, flags); + + if (IS_ERR(comp_opts)) + return comp_opts; + + stream = squashfs_decompressor_create(msblk, comp_opts); + if (IS_ERR(stream)) + kfree(comp_opts); - return strm; + return stream; } -- cgit v1.2.3