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authorPhillip Lougher <phillip@squashfs.org.uk>2013-11-13 06:56:26 +0400
committerPhillip Lougher <phillip@squashfs.org.uk>2013-11-20 07:35:18 +0400
commit9508c6b90b3f57ecea4e7a896cf8325400fc0c6e (patch)
treea31589009d7d85d722b52c0ef21838ca6d2888da /fs/squashfs/decompressor_single.c
parent959f58544b7f20c92d5eb43d1232c96c15c01bfb (diff)
downloadlinux-9508c6b90b3f57ecea4e7a896cf8325400fc0c6e.tar.xz
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/decompressor_single.c')
-rw-r--r--fs/squashfs/decompressor_single.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/fs/squashfs/decompressor_single.c b/fs/squashfs/decompressor_single.c
new file mode 100644
index 000000000000..f857cf6f22d4
--- /dev/null
+++ b/fs/squashfs/decompressor_single.c
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2013
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/buffer_head.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "decompressor.h"
+#include "squashfs.h"
+
+/*
+ * This file implements single-threaded decompression in the
+ * decompressor framework
+ */
+
+struct squashfs_stream {
+ void *stream;
+ struct mutex mutex;
+};
+
+void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
+ void *comp_opts)
+{
+ struct squashfs_stream *stream;
+ int err = -ENOMEM;
+
+ stream = kmalloc(sizeof(*stream), GFP_KERNEL);
+ if (stream == NULL)
+ goto out;
+
+ stream->stream = msblk->decompressor->init(msblk, comp_opts);
+ if (IS_ERR(stream->stream)) {
+ err = PTR_ERR(stream->stream);
+ goto out;
+ }
+
+ kfree(comp_opts);
+ mutex_init(&stream->mutex);
+ return stream;
+
+out:
+ kfree(stream);
+ return ERR_PTR(err);
+}
+
+void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
+{
+ struct squashfs_stream *stream = msblk->stream;
+
+ if (stream) {
+ msblk->decompressor->free(stream->stream);
+ kfree(stream);
+ }
+}
+
+int squashfs_decompress(struct squashfs_sb_info *msblk,
+ void **buffer, struct buffer_head **bh, int b, int offset, int length,
+ int srclength, int pages)
+{
+ int res;
+ struct squashfs_stream *stream = msblk->stream;
+
+ mutex_lock(&stream->mutex);
+ res = msblk->decompressor->decompress(msblk, stream->stream, buffer,
+ bh, b, offset, length, srclength, pages);
+ mutex_unlock(&stream->mutex);
+
+ if (res < 0)
+ ERROR("%s decompression failed, data probably corrupt\n",
+ msblk->decompressor->name);
+
+ return res;
+}
+
+int squashfs_max_decompressors(void)
+{
+ return 1;
+}