[PATCH v2] lib: Documentation: Synchronize %p formatting documentation

Martin Kletzander
2015-09-24T08:09:11Z

Move all pointer-formatting documentation to one place in the code and
one place in the documentation instead of keeping it in three places
with different level of completeness. Documentation/printk-formats.txt
has detailed information about each modifier, docstring above pointer()
has short descriptions of them (as that is the function dealing with %p)
and docstring above vsprintf() is removed as redundant. Both docstrings
in the code that were modified are updated with a reminder of updating
the documentation upon any further change.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
---
Documentation/printk-formats.txt | 27 +++++++++++++++++++++++++
lib/vsprintf.c | 43 ++++++++--------------------------------
2 files changed, 35 insertions(+), 35 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..9ab68775b840 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1463,7 +1463,10 @@ int kptr_restrict __read_mostly;
* - '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
+ * - 'T' For task_struct->comm
+ * - 'n' For ignored argument
+ *
+ * ** Please update Documentation/printk-formats.txt when making changes **
*
* Note: The difference between 'S' and 'F' is that on ia64 and ppc64
* function pointers are really function descriptors, which contain a
@@ -1829,41 +1832,11 @@ 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. See
+ * pointer() or Documentation/printk-formats.txt for all format
+ * specifiers.
*
- * ** 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