Messages in this thread | | | Date | Mon, 14 Oct 2013 11:11:45 +0900 | From | Minchan Kim <> | Subject | Re: [PATCH] Squashfs: Refactor decompressor interface and code |
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On Tue, Oct 08, 2013 at 03:14:10AM +0100, Phillip Lougher wrote: > 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 > > This has the following functions > > decompressor_create() > - Called at mount time to initialise internal decompressor state. > - An opaque pointer to the decompressor private state is returned (or error). > - The function is called with a pointer to the parsed and swapped comp_opts > structure returned by the new decompressor comp_opts() call. > > decompressor_destroy() > - Destroy all decompressor private state > - kfree the comp_opts buffer > > decompress() > - Select a decompressor or create a new decompressor > - Call using whatever locking scheme is necessary > > All decompressor implementation specific private state has been moved from the > squashfs_sb_info structure into the opaque private state returned by > decompressor_create(). This is deliberate, now all implementation specific > code has been moved to decompressor_xxx.c, no other code needs to/or should need > to access anything within it. > > Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> > --- > fs/squashfs/Makefile | 2 +- > fs/squashfs/block.c | 11 ++-- > fs/squashfs/decompressor.c | 47 +++++++++++------ > fs/squashfs/decompressor.h | 21 +++----- > fs/squashfs/decompressor_single.c | 107 ++++++++++++++++++++++++++++++++++++++ > fs/squashfs/lzo_wrapper.c | 24 ++------- > fs/squashfs/squashfs.h | 9 +++- > fs/squashfs/squashfs_fs_sb.h | 3 +- > fs/squashfs/super.c | 10 ++-- > fs/squashfs/xz_wrapper.c | 89 +++++++++++++++++-------------- > fs/squashfs/zlib_wrapper.c | 50 ++++++------------ > 11 files changed, 237 insertions(+), 136 deletions(-) > create mode 100644 fs/squashfs/decompressor_single.c > > diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile > index 110b047..c223c84 100644 > --- a/fs/squashfs/Makefile > +++ b/fs/squashfs/Makefile > @@ -4,7 +4,7 @@ > > obj-$(CONFIG_SQUASHFS) += squashfs.o > squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o > -squashfs-y += namei.o super.o symlink.o decompressor.o > +squashfs-y += namei.o super.o symlink.o decompressor.o decompressor_single.o > squashfs-$(CONFIG_SQUASHFS_XATTR) += xattr.o xattr_id.o > squashfs-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o > squashfs-$(CONFIG_SQUASHFS_XZ) += xz_wrapper.o > diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c > index 41d108e..10993e9 100644 > --- a/fs/squashfs/block.c > +++ b/fs/squashfs/block.c > @@ -93,7 +93,7 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index, > struct buffer_head **bh; > int offset = index & ((1 << msblk->devblksize_log2) - 1); > u64 cur_index = index >> msblk->devblksize_log2; > - int bytes, compressed, b = 0, k = 0, page = 0, avail; > + int bytes, compressed, b = 0, k = 0, page = 0, avail, i; > > bh = kcalloc(((srclength + msblk->devblksize - 1) > >> msblk->devblksize_log2) + 1, sizeof(*bh), GFP_KERNEL); > @@ -158,6 +158,12 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index, > ll_rw_block(READ, b - 1, bh + 1); > } > > + for (i = 0; i < b; i++) { > + wait_on_buffer(bh[i]); > + if (!buffer_uptodate(bh[i])) > + goto block_release; > + }
Please, use tab instead of white space.
-- Kind regards, Minchan Kim
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