vsprintf: add support of '%*ph[CDN]'
There are many places in the kernel where the drivers print small buffers
as a hex string. This patch adds a support of the variable width buffer
to print it as a hex string with a delimiter. The idea came from Pavel
Roskin here: http://www.digipedia.pl/usenet/thread/18835/17449/
Sample output of
pr_info("buf[%d:%d] %*phC\n", from, len, len, &buf[from]);
could be look like this:
[ 0.726130] buf[51:8] e8:16:b6:ef:e3:74:45:6e
[ 0.750736] buf[59:15] 31:81:b8:3f:35:49:06:ae:df:32:06:05:4a:af:55
[ 0.757602] buf[17:5] ac:16:d5:2c:ef
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index d8d168f..7561d7e 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -53,6 +53,16 @@
For printing struct resources. The 'R' and 'r' specifiers result in a
printed resource with ('R') or without ('r') a decoded flags member.
+Raw buffer as a hex string:
+ %*ph 00 01 02 ... 3f
+ %*phC 00:01:02: ... :3f
+ %*phD 00-01-02- ... -3f
+ %*phN 000102 ... 3f
+
+ For printing a small buffers (up to 64 bytes long) as a hex string with
+ certain separator. For the larger buffers consider to use
+ print_hex_dump().
+
MAC/FDDI addresses:
%pM 00:01:02:03:04:05
