On Wed, 20 Aug 2008, Jared Hulbert wrote:
Handles the decompression for axfs, modeled after fs/cramfs/uncompress.c.
Signed-off-by: Jared Hulbert [EMAIL PROTECTED]
---
diff --git a/fs/axfs/axfs_uncompress.c b/fs/axfs/axfs_uncompress.c
new file mode 100644
index 000..b7a2060
--- /dev/null
+++ b/fs/axfs/axfs_uncompress.c
@@ -0,0 +1,97 @@
+/*
+ * Advanced XIP File System for Linux - AXFS
+ * Readonly, compressed, and XIP filesystem for Linux systems big and small
+ *
+ * Modified in 2006 by Eric Anderson
+ * from the cramfs sources fs/cramfs/uncompress.c
+ *
+ * (C) Copyright 1999 Linus Torvalds
+ *
+ * axfs_uncompress.c -
+ * axfs interfaces to the uncompression library. There's really just
+ * three entrypoints:
+ *
+ * - axfs_uncompress_init() - called to initialize the thing.
+ * - axfs_uncompress_exit() - tell me when you're done
+ * - axfs_uncompress_block() - uncompress a block.
+ *
+ * NOTE NOTE NOTE! The uncompression is entirely single-threaded. We
+ * only have one stream, and we'll initialize it only once even if it
+ * then is used by multiple filesystems.
+ *
+ */
+
+#include linux/errno.h
+#include linux/vmalloc.h
+#include linux/zlib.h
+#include linux/mutex.h
+
+static z_stream stream;
+static int initialized;
+static struct mutex axfs_uncmp_mutex;
Use DEFINE_MUTEX and drop the mutex_init() down in the init function.
+
+int axfs_uncompress_block(void *dst, int dstlen, void *src, int srclen)
+{
+ int err;
+ int out;
+
+ mutex_lock(axfs_uncmp_mutex);
+
+ stream.next_in = src;
+ stream.avail_in = srclen;
+
+ stream.next_out = dst;
+ stream.avail_out = dstlen;
+
+ err = zlib_inflateReset(stream);
+ if (err != Z_OK) {
+ printk(KERN_ERR zlib_inflateReset error %d\n, err);
+ zlib_inflateEnd(stream);
+ zlib_inflateInit(stream);
+ }
+
+ err = zlib_inflate(stream, Z_FINISH);
+ if (err != Z_STREAM_END)
+ goto err;
+
+ out = stream.total_out;
+
+ mutex_unlock(axfs_uncmp_mutex);
+
+ return out;
+
+err:
+
+ mutex_unlock(axfs_uncmp_mutex);
+
+ printk(KERN_ERR Error %d while decompressing!\n, err);
+ printk(KERN_ERR %p(%d)-%p(%d)\n, src, srclen, dst, dstlen);
+ return 0;
+}
+
+int axfs_uncompress_init(void)
+{
+ if (!initialized++) {
+
+ mutex_init(axfs_uncmp_mutex);
+
+ stream.workspace = vmalloc(zlib_inflate_workspacesize());
+ if (!stream.workspace) {
+ initialized = 0;
+ return -ENOMEM;
+ }
+ stream.next_in = NULL;
+ stream.avail_in = 0;
+ zlib_inflateInit(stream);
+ }
+ return 0;
+}
+
+int axfs_uncompress_exit(void)
+{
+ if (!--initialized) {
+ zlib_inflateEnd(stream);
+ vfree(stream.workspace);
+ }
+ return 0;
+}
axfs_uncompress_init() and axfs_uncompress_exit() are only called during
init and exit of the module, no need for the initialized variable and the
functions can be annotated with __init and __exit.
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