hexdump: make it return number of bytes placed in buffer

This patch makes hexdump return the number of bytes placed in the buffer
excluding trailing NUL.  In the case of overflow it returns the desired
amount of bytes to produce the entire dump.  Thus, it mimics snprintf().

This will be useful for users that would like to repeat with a bigger
buffer.

[akpm@linux-foundation.org: fix printk warning]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/include/linux/printk.h b/include/linux/printk.h
index 4d5bf5726578..baa3f97d8ce8 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -417,9 +417,9 @@ enum {
         DUMP_PREFIX_ADDRESS,
         DUMP_PREFIX_OFFSET
 };
-extern void hex_dump_to_buffer(const void *buf, size_t len,
-                               int rowsize, int groupsize,
-                               char *linebuf, size_t linebuflen, bool ascii);
+extern int hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
+                              int groupsize, char *linebuf, size_t linebuflen,
+                              bool ascii);
 #ifdef CONFIG_PRINTK
 extern void print_hex_dump(const char *level, const char *prefix_str,
                            int prefix_type, int rowsize, int groupsize,