From: Daniel M. Weeks <dan@danweeks.net>
Date: Mon, 7 Apr 2014 22:39:16 +0000 (-0700)
Subject: initramfs: debug detected compression method
X-Git-Tag: v3.15-rc1~57^2~33
X-Git-Url: http://git.agner.ch/gitweb/?a=commitdiff_plain;h=6aa7a29aa8378fa868fabef6a84b0a40d5d9d677;p=linux.git

initramfs: debug detected compression method

This can greatly aid in narrowing down the real source of initramfs
problems such as failures related to the compression of the in-kernel
initramfs when an external initramfs is in use as well.  Existing errors
are ambiguous as to which initramfs is a problem and why.

[akpm@linux-foundation.org: use pr_debug()]
Signed-off-by: Daniel M. Weeks <dan@danweeks.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/init/initramfs.c b/init/initramfs.c
index 93b61396756b..a8497fab1c3d 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -455,6 +455,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned len)
 		}
 		this_header = 0;
 		decompress = decompress_method(buf, len, &compress_name);
+		pr_debug("Detected %s compressed data\n", compress_name);
 		if (decompress) {
 			res = decompress(buf, len, NULL, flush_buffer, NULL,
 				   &my_inptr, error);
diff --git a/lib/decompress.c b/lib/decompress.c
index 4d1cd0397aab..86069d74c062 100644
--- a/lib/decompress.c
+++ b/lib/decompress.c
@@ -16,6 +16,7 @@
 #include <linux/types.h>
 #include <linux/string.h>
 #include <linux/init.h>
+#include <linux/printk.h>
 
 #ifndef CONFIG_DECOMPRESS_GZIP
 # define gunzip NULL
@@ -61,6 +62,8 @@ decompress_fn __init decompress_method(const unsigned char *inbuf, int len,
 	if (len < 2)
 		return NULL;	/* Need at least this much... */
 
+	pr_debug("Compressed data magic: %#.2x %#.2x\n", inbuf[0], inbuf[1]);
+
 	for (cf = compressed_formats; cf->name; cf++) {
 		if (!memcmp(inbuf, cf->magic, 2))
 			break;