MAC addresses may be formed using rules based on EUI-64, which is 2 bytes
longer than a typical 6-byte MAC. This patch adds a long specifier to
the %pM format to support the extended unique identifier.

Since there are now two cases that use the default ':' separator, this
initializes the separator during its declaration, and removes the switch
fall through case.

Signed-off-by: Keith Busch <[email protected]>
---
Changed from previos version:

  Fixed checks for the 'l' specifier. This can be in fmt[1] or fmt[2],
  pointed out by Joe Perches from original review (thanks!).

 Documentation/printk-formats.txt | 13 ++++++++++---
 lib/vsprintf.c                   | 31 +++++++++++++++++++++++--------
 2 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index b784c27..e2fe4ed 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -136,14 +136,21 @@ Raw buffer as a hex string:
 MAC/FDDI addresses:
 
        %pM     00:01:02:03:04:05
+       %pMl    00:01:02:03:04:05:06:07
        %pMR    05:04:03:02:01:00
+       %pMRl   07:06:05:04:03:02:01:00
        %pMF    00-01-02-03-04-05
+       %pMFl   00-01-02-03-04-05-06-07
        %pm     000102030405
+       %pml    0001020304050607
        %pmR    050403020100
+       %pmRl   0706050403020100
 
-       For printing 6-byte MAC/FDDI addresses in hex notation. The 'M' and 'm'
-       specifiers result in a printed address with ('M') or without ('m') byte
-       separators. The default byte separator is the colon (':').
+       For printing 6 or 8-byte MAC/FDDI addresses in hex notation. The
+       'M' and 'm' specifiers result in a printed address with ('M')
+       or without ('m') byte separators. The default byte separator is
+       the colon (':'). Append 'l' to specify an 8-byte in accordance
+       with EUI-64 format.
 
        Where FDDI addresses are concerned the 'F' specifier can be used after
        the 'M' specifier to use dash ('-') separators instead of the default
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index f9cee8e..a5eb82c 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -889,10 +889,10 @@ static noinline_for_stack
 char *mac_address_string(char *buf, char *end, u8 *addr,
                         struct printf_spec spec, const char *fmt)
 {
-       char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
+       char mac_addr[sizeof("xx:xx:xx:xx:xx:xx:xx:xx")];
        char *p = mac_addr;
-       int i;
-       char separator;
+       int i, bytes = 6;
+       char separator = ':';
        bool reversed = false;
 
        switch (fmt[1]) {
@@ -902,20 +902,33 @@ char *mac_address_string(char *buf, char *end, u8 *addr,
 
        case 'R':
                reversed = true;
-               /* fall through */
+               break;
+
+       case 'l':
+               bytes = 8;
+               break;
 
        default:
-               separator = ':';
                break;
        }
+       if (separator == '-' || reversed) {
+               /* 'F' and 'R' may take additional length specifier */
+               switch (fmt[2]) {
+               case 'l':
+                       bytes = 8;
+                       break;
+               default:
+                       break;
+               }
+       }
 
-       for (i = 0; i < 6; i++) {
+       for (i = 0; i < bytes; i++) {
                if (reversed)
-                       p = hex_byte_pack(p, addr[5 - i]);
+                       p = hex_byte_pack(p, addr[(bytes - 1) - i]);
                else
                        p = hex_byte_pack(p, addr[i]);
 
-               if (fmt[0] == 'M' && i != 5)
+               if (fmt[0] == 'M' && i != (bytes - 1))
                        *p++ = separator;
        }
        *p = '\0';
@@ -1496,6 +1509,8 @@ char *pointer(const char *fmt, char *buf, char *end, void 
*ptr,
        case 'm':                       /* Contiguous: 000102030405 */
                                        /* [mM]F (FDDI) */
                                        /* [mM]R (Reverse order; Bluetooth) */
+                                       /* [mM]l (EUI-64) */
+                                       /* [mM][FR]l (FDDI/Reverse order 
EUI-64) */
                return mac_address_string(buf, end, ptr, spec, fmt);
        case 'I':                       /* Formatted IP supported
                                         * 4:   1.2.3.4
-- 
2.6.2.307.g37023ba

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