Message-Id: <32a3a9cbcdd7ffe76ad84b8f318eefe3392e97e0.1442826483.git.mkletzan@redhat.com>
Date:	Mon, 21 Sep 2015 11:13:40 +0200
From:	Martin Kletzander <mkletzan@...hat.com>
To:	linux-doc@...r.kernel.org
Cc:	Jonathan Corbet <corbet@....net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
	Stephen Boyd <sboyd@...eaurora.org>, Tejun Heo <tj@...nel.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] lib: Documentation: Synchronize %p formatting documentation

Move all pointer-formatting documentation to one place instead of
keeping it in three places with different level of completeness.

Signed-off-by: Martin Kletzander <mkletzan@...hat.com>
---
 Documentation/printk-formats.txt |  27 +++++++++
 lib/vsprintf.c                   | 123 ++-------------------------------------
 2 files changed, 32 insertions(+), 118 deletions(-)

diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 2ec6d84f391c..c85e27264a2b 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -119,6 +119,7 @@ Raw buffer as an escaped string:
 	If field width is omitted the 1 byte only will be escaped.

 Raw buffer as a hex string:
+
 	%*ph	00 01 02  ...  3f
 	%*phC	00:01:02: ... :3f
 	%*phD	00-01-02- ... -3f
@@ -234,6 +235,7 @@ UUID/GUID addresses:
 	Passed by reference.

 dentry names:
+
 	%pd{,2,3,4}
 	%pD{,2,3,4}

@@ -264,6 +266,8 @@ struct va_format:
 		va_list *va;
 	};

+	Implements a "recursive vsnprintf".
+
 	Do not use this feature without some mechanism to verify the
 	correctness of the format string and va_list arguments.

@@ -292,6 +296,29 @@ bitmap and its derivatives such as cpumask and nodemask:

 	Passed by reference.

+Network device features:
+
+	%pNF	0x000000000000c000
+
+	For printing netdev_features_t.
+
+	Passed by reference.
+
+Command from struct task_struct
+
+	%pT	ls
+
+	For printing executable name excluding path from struct
+	task_struct.
+
+	Passed by reference.
+
+Ignored argument:
+
+	%pn
+
+	The argument passed will be ignored.
+
 Thank you for your cooperation and attention.


diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index becd87facf48..6e358dc81ef0 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1383,91 +1383,9 @@ int kptr_restrict __read_mostly;
  * by an extra set of alphanumeric characters that are extended format
  * specifiers.
  *
- * Right now we handle:
+ * All format specifiers are documented in Documentation/printk-formats.txt.
  *
- * - 'F' For symbolic function descriptor pointers with offset
- * - 'f' For simple symbolic function names without offset
- * - 'S' For symbolic direct pointers with offset
- * - 's' For symbolic direct pointers without offset
- * - '[FfSs]R' as above with __builtin_extract_return_addr() translation
- * - 'B' For backtraced symbolic direct pointers with offset
- * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
- * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
- * - 'b[l]' For a bitmap, the number of bits is determined by the field
- *       width which must be explicitly specified either as part of the
- *       format string '%32b[l]' or through '%*b[l]', [l] selects
- *       range-list format instead of hex format
- * - 'M' For a 6-byte MAC address, it prints the address in the
- *       usual colon-separated hex notation
- * - 'm' For a 6-byte MAC address, it prints the hex address without colons
- * - 'MF' For a 6-byte MAC FDDI address, it prints the address
- *       with a dash-separated hex notation
- * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
- * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
- *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
- *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
- *       [S][pfs]
- *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
- *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
- * - 'i' [46] for 'raw' IPv4/IPv6 addresses
- *       IPv6 omits the colons (01020304...0f)
- *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
- *       [S][pfs]
- *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
- *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
- * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order
- * - 'I[6S]c' for IPv6 addresses printed as specified by
- *       http://tools.ietf.org/html/rfc5952
- * - 'E[achnops]' For an escaped buffer, where rules are defined by combination
- *                of the following flags (see string_escape_mem() for the
- *                details):
- *                  a - ESCAPE_ANY
- *                  c - ESCAPE_SPECIAL
- *                  h - ESCAPE_HEX
- *                  n - ESCAPE_NULL
- *                  o - ESCAPE_OCTAL
- *                  p - ESCAPE_NP
- *                  s - ESCAPE_SPACE
- *                By default ESCAPE_ANY_NP is used.
- * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
- *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
- *       Options for %pU are:
- *         b big endian lower case hex (default)
- *         B big endian UPPER case hex
- *         l little endian lower case hex
- *         L little endian UPPER case hex
- *           big endian output byte order is:
- *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
- *           little endian output byte order is:
- *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
- * - 'V' For a struct va_format which contains a format string * and va_list *,
- *       call vsnprintf(->format, *->va_list).
- *       Implements a "recursive vsnprintf".
- *       Do not use this feature without some mechanism to verify the
- *       correctness of the format string and va_list arguments.
- * - 'K' For a kernel pointer that should be hidden from unprivileged users
- * - 'NF' For a netdev_features_t
- * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
- *            a certain separator (' ' by default):
- *              C colon
- *              D dash
- *              N no separator
- *            The maximum supported length is 64 bytes of the input. Consider
- *            to use print_hex_dump() for the larger input.
- * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives
- *           (default assumed to be phys_addr_t, passed by reference)
- * - 'd[234]' For a dentry name (optionally 2-4 last components)
- * - 'D[234]' Same as 'd' but for a struct file
- * - 'C' For a clock, it prints the name (Common Clock Framework) or address
- *       (legacy clock framework) of the clock
- * - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
- *        (legacy clock framework) of the clock
- * - 'Cr' For a clock, it prints the current rate of the clock
- * - 'T' task_struct->comm
- *
- * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
- * function pointers are really function descriptors, which contain a
- * pointer to the real address.
+ * ** Please update the documentation when making changes **
  */
 static noinline_for_stack
 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
@@ -1829,41 +1747,10 @@ qualifier:
  * @fmt: The format string to use
  * @args: Arguments for the format string
  *
- * This function follows C99 vsnprintf, but has some extensions:
- * %pS output the name of a text symbol with offset
- * %ps output the name of a text symbol without offset
- * %pF output the name of a function pointer with its offset
- * %pf output the name of a function pointer without its offset
- * %pB output the name of a backtrace symbol with its offset
- * %pR output the address range in a struct resource with decoded flags
- * %pr output the address range in a struct resource with raw flags
- * %pb output the bitmap with field width as the number of bits
- * %pbl output the bitmap as range list with field width as the number of bits
- * %pM output a 6-byte MAC address with colons
- * %pMR output a 6-byte MAC address with colons in reversed order
- * %pMF output a 6-byte MAC address with dashes
- * %pm output a 6-byte MAC address without colons
- * %pmR output a 6-byte MAC address without colons in reversed order
- * %pI4 print an IPv4 address without leading zeros
- * %pi4 print an IPv4 address with leading zeros
- * %pI6 print an IPv6 address with colons
- * %pi6 print an IPv6 address without colons
- * %pI6c print an IPv6 address as specified by RFC 5952
- * %pIS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
- * %piS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
- * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
- *   case.
- * %*pE[achnops] print an escaped buffer
- * %*ph[CDN] a variable-length hex string with a separator (supports up to 64
- *           bytes of the input)
- * %pC output the name (Common Clock Framework) or address (legacy clock
- *     framework) of a clock
- * %pCn output the name (Common Clock Framework) or address (legacy clock
- *      framework) of a clock
- * %pCr output the current rate of a clock
- * %n is ignored
+ * This function follows C99 vsnprintf, but has some extensions.
+ * All format specifiers are documented in Documentation/printk-formats.txt.
  *
- * ** Please update Documentation/printk-formats.txt when making changes **
+ * ** Please update the documentation when making changes **
  *
  * The return value is the number of characters which would
  * be generated for the given input, excluding the trailing
-- 
2.5.3

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