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authorPhillip Lougher <phillip@squashfs.org.uk>2013-11-13 03:56:26 +0100
committerPhillip Lougher <phillip@squashfs.org.uk>2013-11-20 04:35:18 +0100
commit9508c6b90b3f57ecea4e7a896cf8325400fc0c6e (patch)
treea31589009d7d85d722b52c0ef21838ca6d2888da /fs/squashfs/xz_wrapper.c
parentLinux 3.12-rc7 (diff)
downloadlinux-9508c6b90b3f57ecea4e7a896cf8325400fc0c6e.tar.xz
linux-9508c6b90b3f57ecea4e7a896cf8325400fc0c6e.zip
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 <phillip@squashfs.org.uk> Reviewed-by: Minchan Kim <minchan@kernel.org>
Diffstat (limited to 'fs/squashfs/xz_wrapper.c')
-rw-r--r--fs/squashfs/xz_wrapper.c89
1 files changed, 49 insertions, 40 deletions
diff --git a/fs/squashfs/xz_wrapper.c b/fs/squashfs/xz_wrapper.c
index 1760b7d108f6..5d1d07cca6b4 100644
--- a/fs/squashfs/xz_wrapper.c
+++ b/fs/squashfs/xz_wrapper.c
@@ -38,38 +38,63 @@ struct squashfs_xz {
struct xz_buf buf;
};
-struct comp_opts {
+struct disk_comp_opts {
__le32 dictionary_size;
__le32 flags;
};
-static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff,
- int len)
+struct comp_opts {
+ int dict_size;
+};
+
+static void *squashfs_xz_comp_opts(struct squashfs_sb_info *msblk,
+ void *buff, int len)
{
- struct comp_opts *comp_opts = buff;
- struct squashfs_xz *stream;
- int dict_size = msblk->block_size;
- int err, n;
+ struct disk_comp_opts *comp_opts = buff;
+ struct comp_opts *opts;
+ int err = 0, n;
+
+ opts = kmalloc(sizeof(*opts), GFP_KERNEL);
+ if (opts == NULL) {
+ err = -ENOMEM;
+ goto out2;
+ }
if (comp_opts) {
/* check compressor options are the expected length */
if (len < sizeof(*comp_opts)) {
err = -EIO;
- goto failed;
+ goto out;
}
- dict_size = le32_to_cpu(comp_opts->dictionary_size);
+ opts->dict_size = le32_to_cpu(comp_opts->dictionary_size);
/* the dictionary size should be 2^n or 2^n+2^(n+1) */
- n = ffs(dict_size) - 1;
- if (dict_size != (1 << n) && dict_size != (1 << n) +
+ n = ffs(opts->dict_size) - 1;
+ if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) +
(1 << (n + 1))) {
err = -EIO;
- goto failed;
+ goto out;
}
- }
+ } else
+ /* use defaults */
+ opts->dict_size = max_t(int, msblk->block_size,
+ SQUASHFS_METADATA_SIZE);
- dict_size = max_t(int, dict_size, SQUASHFS_METADATA_SIZE);
+ return opts;
+
+out:
+ kfree(opts);
+out2:
+ return ERR_PTR(err);
+}
+
+
+static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff)
+{
+ struct comp_opts *comp_opts = buff;
+ struct squashfs_xz *stream;
+ int err;
stream = kmalloc(sizeof(*stream), GFP_KERNEL);
if (stream == NULL) {
@@ -77,7 +102,7 @@ static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff,
goto failed;
}
- stream->state = xz_dec_init(XZ_PREALLOC, dict_size);
+ stream->state = xz_dec_init(XZ_PREALLOC, comp_opts->dict_size);
if (stream->state == NULL) {
kfree(stream);
err = -ENOMEM;
@@ -103,15 +128,13 @@ static void squashfs_xz_free(void *strm)
}
-static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer,
- struct buffer_head **bh, int b, int offset, int length, int srclength,
- int pages)
+static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
+ void **buffer, struct buffer_head **bh, int b, int offset, int length,
+ int srclength, int pages)
{
enum xz_ret xz_err;
int avail, total = 0, k = 0, page = 0;
- struct squashfs_xz *stream = msblk->stream;
-
- mutex_lock(&msblk->read_data_mutex);
+ struct squashfs_xz *stream = strm;
xz_dec_reset(stream->state);
stream->buf.in_pos = 0;
@@ -124,10 +147,6 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer,
if (stream->buf.in_pos == stream->buf.in_size && k < b) {
avail = min(length, msblk->devblksize - offset);
length -= avail;
- wait_on_buffer(bh[k]);
- if (!buffer_uptodate(bh[k]))
- goto release_mutex;
-
stream->buf.in = bh[k]->b_data + offset;
stream->buf.in_size = avail;
stream->buf.in_pos = 0;
@@ -147,23 +166,12 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void **buffer,
put_bh(bh[k++]);
} while (xz_err == XZ_OK);
- if (xz_err != XZ_STREAM_END) {
- ERROR("xz_dec_run error, data probably corrupt\n");
- goto release_mutex;
- }
-
- if (k < b) {
- ERROR("xz_uncompress error, input remaining\n");
- goto release_mutex;
- }
-
- total += stream->buf.out_pos;
- mutex_unlock(&msblk->read_data_mutex);
- return total;
+ if (xz_err != XZ_STREAM_END || k < b)
+ goto out;
-release_mutex:
- mutex_unlock(&msblk->read_data_mutex);
+ return total + stream->buf.out_pos;
+out:
for (; k < b; k++)
put_bh(bh[k]);
@@ -172,6 +180,7 @@ release_mutex:
const struct squashfs_decompressor squashfs_xz_comp_ops = {
.init = squashfs_xz_init,
+ .comp_opts = squashfs_xz_comp_opts,
.free = squashfs_xz_free,
.decompress = squashfs_xz_uncompress,
.id = XZ_COMPRESSION,