Commit Graph

41 Commits

Author SHA1 Message Date
Zhaolei
022624a758 printk: fix wrong format string iter for printk
printk("%Q");

 Output before patch:  %QQ
 Output  after patch:  %Q

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Acked-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: torvalds@linux-foundation.org
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49CC97B6.7040809@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-08 17:03:44 +02:00
Vegard Nossum
ed681a91ab vsprintf: unify the format decoding layer for its 3 users, cleanup
Impact: cleanup

Rename FORMAT_TYPE_WITDH
 to => FORMAT_TYPE_WIDTH

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-14 12:37:09 +01:00
Vegard Nossum
adf26f84a6 fix regression from "vsprintf: unify the format decoding layer for its 3 users"
Jeremy Fitzhardinge reported:

> Change fef20d9c13, "vsprintf:
> unify the format decoding layer for its 3 users", causes a
> regression in xenbus which results in no devices getting
> attached to a new domain.

%.*s is broken - fix it.

Reported-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-14 12:37:08 +01:00
Frederic Weisbecker
39e874f8af vsprintf: fix bug in negative value printing
Sitsofe Wheeler found and bisected that while unifying the
vsprintf format decoding in:

  fef20d9: vsprintf: unify the format decoding layer for its 3 users

The sign flag has been dropped out in favour of
precise types (ie: LONG/ULONG).

But the format helper number() still needs this flag to keep track of
the signedness unless it will consider all numbers as unsigned.

Also add an explicit cast to int (for %d) while parsing with va_arg()
to ensure the highest bit is well extended on the 64 bits number that
hosts the value in case of negative values.

Reported-Bisected-Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20090309201503.GA5010@nowhere>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-10 13:15:06 +01:00
Frederic Weisbecker
fef20d9c13 vsprintf: unify the format decoding layer for its 3 users
An new optimization is making its way to ftrace. Its purpose is to
make trace_printk() consuming less memory and be faster.

Written by Lai Jiangshan, the approach is to delay the formatting
job from tracing time to output time.

Currently, a call to trace_printk() will format the whole string and
insert it into the ring buffer. Then you can read it on /debug/tracing/trace
file.

The new implementation stores the address of the format string and
the binary parameters into the ring buffer, making the packet more compact
and faster to insert.
Later, when the user exports the traces, the format string is retrieved
with the binary parameters and the formatting job is eventually done.

The new implementation rewrites a lot of format decoding bits from
vsnprintf() function, making now 3 differents functions to maintain
in their duplicated parts of printf format decoding bits.

Suggested by Ingo Molnar, this patch tries to factorize the most
possible common bits from these functions.
The real common part between them is the format decoding. Although
they do somewhat similar jobs, their way to export or import the parameters
is very different. Thus, only the decoding layer is extracted, unless you see
other parts that could be worth factorized.

Changes in V2:

- Address a suggestion from Linus to group the format_decode() parameters inside
  a structure.

Changes in v3:

- Address other cleanups suggested by Ingo and Linus such as passing the
  printf_spec struct to the format helpers: pointer()/number()/string()
  Note that this struct is passed by copy and not by address. This is to
  avoid side effects because these functions often change these values and the
  changes shoudn't be persistant when a callee helper returns.
  It would be too risky.

- Various cleanups (code alignement, switch/case instead of if/else fountains).

- Fix a bug that printed the first format specifier following a %p

Changes in v4:

- drop unapropriate const qualifier loss while casting fmt to a char *
  (thanks to Vegard Nossum for having pointed this out).

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:44:27 +01:00
Lai Jiangshan
4370aa4aa7 vsprintf: add binary printf
Impact: add new APIs for binary trace printk infrastructure

vbin_printf(): write args to binary buffer, string is copied
when "%s" is occurred.

bstr_printf(): read from binary buffer for args and format a string

[fweisbec@gmail.com: rebase]

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1236356510-8381-2-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-06 17:39:04 +01:00
Pavel Machek
e899aa823a strict_strto* is not strict enough
It decodes "\n" as 0, which is bad, because stray echo into backlight
will turn your backlight off, etc...

Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: Yi Yang <yi.y.yang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:12 -08:00
Linus Torvalds
d97106ab53 Make %p print '(null)' for NULL pointers
Before, when we only ever printed out the pointer value itself, a NULL
pointer would never cause issues and might as well be printed out as
just its numeric value.

However, with the extended %p formats, especially %pR, we might validly
want to print out resources for debugging.  And sometimes they don't
even exist, and the resource pointer is just NULL.  Print it out as
such, rather than oopsing.

This is a more generic version of a patch done by Trent Piepho (catching
all %p cases rather than just %pR, and using "(null)" instead of
"[NULL]" to match glibc).

Requested-by: Trent Piepho <xyzzy@speakeasy.org>
Acked-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-03 11:46:17 -08:00
Harvey Harrison
411c41eea5 aoe: remove private mac address format function
Add %pm to omit the colons when printing a mac address.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25 00:40:37 -08:00
Harvey Harrison
b9ac99855d printk: ipv4 address digits printed in reverse order
put_dec_trunc prints the digits in reverse order and is reversed
inside number(). Continue using put_dec_trunc, but reverse each quad
in ip4_addr_string.

[Noticed by Julius Volz]

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-03 17:09:55 -08:00
Harvey Harrison
6b9a1066f8 printk: remove %p6 format specifier, fix up comments
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-29 12:53:10 -07:00
Harvey Harrison
4aa996066f printk: add %I4, %I6, %i4, %i6 format specifiers
For use in printing IPv4, or IPv6 addresses in the usual way:

%i4 and %I4 are currently equivalent and print the address in
dot-separated decimal x.x.x.x

%I6 prints 16-bit network order hex with colon separators:
xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx

%i6 omits the colons.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-29 12:49:58 -07:00
Harvey Harrison
689afa7da1 printk: add %p6 format specifier for IPv6 addresses
Takes a pointer to a IPv6 address and formats it in the usual
colon-separated hex format:
xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx

Each 16 bit word is printed in network-endian byteorder.

%#p6 is also supported and will omit the colons.

%p6 is a replacement for NIP6_FMT and NIP6()
%#p6 is a replacement for NIP6_SEQFMT and NIP6()

Note that NIP6() took a struct in6_addr whereas this takes a pointer
to a struct in6_addr.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-28 16:04:44 -07:00
Harvey Harrison
dd45c9cf68 printk: add %pM format specifier for MAC addresses
Add format specifiers for printing out six colon-separated bytes:

MAC addresses (%pM):
xx:xx:xx:xx:xx:xx

%#pM is also supported and omits the colon separators.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-27 17:06:15 -07:00
Linus Torvalds
332d2e7834 Implement %pR to print struct resource content
Add a %pR option to the kernel vsnprintf that prints the range of
addresses inside a struct resource passed by pointer.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 09:12:32 -07:00
Harvey Harrison
9d85db2244 lib: remove defining macros for strict_strto??
Open-code them rather than using defining macros.  The function bodies are now
next to their kerneldoc comments as a bonus.

Add casts to the signed cases as they call into the unsigned versions.

Avoids the sparse warnings:
lib/vsprintf.c:249:1: warning: incorrect type in argument 3 (different signedness)
lib/vsprintf.c:249:1:    expected unsigned long *res
lib/vsprintf.c:249:1:    got long *res
lib/vsprintf.c:249:1: warning: incorrect type in argument 3 (different signedness)
lib/vsprintf.c:249:1:    expected unsigned long *res
lib/vsprintf.c:249:1:    got long *res
lib/vsprintf.c:251:1: warning: incorrect type in argument 3 (different signedness)
lib/vsprintf.c:251:1:    expected unsigned long long *res
lib/vsprintf.c:251:1:    got long long *res
lib/vsprintf.c:251:1: warning: incorrect type in argument 3 (different signedness)
lib/vsprintf.c:251:1:    expected unsigned long long *res
lib/vsprintf.c:251:1:    got long long *res

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 14:58:08 -07:00
Harvey Harrison
22d27051b4 lib: trivial whitespace tidy
Remove extra lines before the EXPORT_SYMBOL()s

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 14:58:07 -07:00
Harvey Harrison
aa46a63efc lib: pull base-guessing logic to helper function
The default base is 10 unless there is a leading zero, in which
case the base will be guessed as 8.

The base will only be guesed as 16 when the string starts with '0x'
the third character is a valid hex digit.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 14:58:07 -07:00
Andi Kleen
20036fdcaf Add kerneldoc documentation for new printk format extensions
Add documentation in kerneldoc for new printk format extensions

This patch documents the new %pS/%pF options in printk in kernel doc.

Hope I didn't miss any other extension.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 11:21:32 -07:00
James Bottomley
deac93df26 lib: Correct printk %pF to work on all architectures
It was introduced by "vsprintf: add support for '%pS' and '%pF' pointer
formats" in commit 0fe1ef24f7.  However,
the current way its coded doesn't work on parisc64.  For two reasons: 1)
parisc isn't in the #ifdef and 2) parisc has a different format for
function descriptors

Make dereference_function_descriptor() more accommodating by allowing
architecture overrides.  I put the three overrides (for parisc64, ppc64
and ia64) in arch/kernel/module.c because that's where the kernel
internal linker which knows how to deal with function descriptors sits.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-09 11:51:15 -07:00
Yi Yang
29a6d39bf3 lib/vsprintf.c: wrong conversion function used
Fix wrong conversion function used by strict_strtou*

Signed-off-by: Yi Yang <yi.y.yang@intel.com>
Reported-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-12 16:07:29 -07:00
Linus Torvalds
0fe1ef24f7 vsprintf: add support for '%pS' and '%pF' pointer formats
They print out a pointer in symbolic format, if possible (ie using
symbolic KALLSYMS information).  The '%pS' format is for regular direct
pointers (which can point to data or code and that you find on the stack
during backtraces etc), while '%pF' is for C function pointer types.

On most architectures, the two mean exactly the same thing, but some
architectures use an indirect pointer for C function pointers, where the
function pointer points to a function descriptor (which in turn contains
the actual pointer to the code).  The '%pF' code automatically does the
appropriate function descriptor dereference on such architectures.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-06 16:55:51 -07:00
Linus Torvalds
4d8a743cdd vsprintf: add infrastructure support for extended '%p' specifiers
This expands the kernel '%p' handling with an arbitrary alphanumberic
specifier extension string immediately following the '%p'.  Right now
it's just being ignored, but the next commit will start adding some
specific pointer type extensions.

NOTE! The reason the extension is appended to the '%p' is to allow
minimal gcc type checking: gcc will still see the '%p' and will check
that the argument passed in is indeed a pointer, and yet will not
complain about the extended information that gcc doesn't understand
about (on the other hand, it also won't actually check that the pointer
type and the extension are compatible).

Alphanumeric characters were chosen because there is no sane existing
use for a string format with a hex pointer representation immediately
followed by alphanumerics (which is what such a format string would have
traditionally resulted in).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-06 16:24:57 -07:00
Linus Torvalds
78a8bf69b3 vsprintf: split out '%p' handling logic
The actual code is the same, just split out into a helper function.
This makes it easier to read, and allows for simple future extension
of %p handling.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-06 16:16:15 -07:00
Linus Torvalds
0f9bfa569d vsprintf: split out '%s' handling logic
The actual code is the same, just split out into a helper function.
This makes it easier to read, and allows for future sharing of the
string code.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-06 16:06:25 -07:00
Hoang-Nam Nguyen
4f9d5f4a35 lib/vsprintf.c: fix bug omitting minus sign of numbers (module_param)
lib/vsprintf.c: Fix bug omitting minus sign of numbers (module_param)

Signed-off-by: Hoang-Nam Nguyen <hnguyen@de.ibm.com>
Cc: Yi Yang <yi.y.yang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-23 17:12:14 -08:00
Denys Vlasenko
9b706aee7d x86: trivial printk optimizations
In arch/x86/boot/printf.c gets rid of unused tail of digits: const char
*digits = "0123456789abcdefghijklmnopqrstuvwxyz"; (we are using 0-9a-f
only)

Uses smaller/faster lowercasing (by ORing with 0x20)
if we know that we work on numbers/digits. Makes
strtoul smaller, and also we are getting rid of

  static const char small_digits[] = "0123456789abcdefx";
  static const char large_digits[] = "0123456789ABCDEFX";

since this works equally well:

  static const char digits[16] = "0123456789ABCDEF";

Size savings:

$ size vmlinux.org vmlinux
   text    data     bss     dec     hex filename
 877320  112252   90112 1079684  107984 vmlinux.org
 877048  112252   90112 1079412  107874 vmlinux

It may be also a tiny bit faster because code has less
branches now, but I doubt it is measurable.

[ hugh@veritas.com: uppercase pointers fix ]

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-09 23:24:09 +01:00
Yi Yang
06b2a76d25 Add new string functions strict_strto* and convert kernel params to use them
Currently, for every sysfs node, the callers will be responsible for
implementing store operation, so many many callers are doing duplicate
things to validate input, they have the same mistakes because they are
calling simple_strtol/ul/ll/uul, especially for module params, they are
just numeric, but you can echo such values as 0x1234xxx, 07777888 and
1234aaa, for these cases, module params store operation just ignores
succesive invalid char and converts prefix part to a numeric although input
is acctually invalid.

This patch tries to fix the aforementioned issues and implements
strict_strtox serial functions, kernel/params.c uses them to strictly
validate input, so module params will reject such values as 0x1234xxxx and
returns an error:

write error: Invalid argument

Any modules which export numeric sysfs node can use strict_strtox instead of
simple_strtox to reject any invalid input.

Here are some test results:

Before applying this patch:

[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000g > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000gggggggg > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 010000 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0100008 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 010000aaaaa > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]#

After applying this patch:

[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000g > /sys/module/e1000/parameters/copybreak
-bash: echo: write error: Invalid argument
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo 0x1000gggggggg > /sys/module/e1000/parameters/copybreak
-bash: echo: write error: Invalid argument
[root@yangyi-dev /]# echo 010000 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# echo 0100008 > /sys/module/e1000/parameters/copybreak
-bash: echo: write error: Invalid argument
[root@yangyi-dev /]# echo 010000aaaaa > /sys/module/e1000/parameters/copybreak
-bash: echo: write error: Invalid argument
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]# echo -n 4096 > /sys/module/e1000/parameters/copybreak
[root@yangyi-dev /]# cat /sys/module/e1000/parameters/copybreak
4096
[root@yangyi-dev /]#

[akpm@linux-foundation.org: fix compiler warnings]
[akpm@linux-foundation.org: fix off-by-one found by tiwai@suse.de]
Signed-off-by: Yi Yang <yi.y.yang@intel.com>
Cc: Greg KH <greg@kroah.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:41 -08:00
Sam Ravnborg
96e3e18eed lib: move kasprintf to a separate file
kasprintf pulls in kmalloc which proved to be fatal for at least
bootimage target on alpha.
Move it to a separate file so only users of kasprintf are exposed
to the dependency on kmalloc.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Meelis Roos <mroos@linux.ee>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jay Estabrook <jay.estabrook@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-31 15:39:39 -07:00
Denis Vlasenko
4277eedd79 vsprintf.c: optimizing, part 2: base 10 conversion speedup, v2
Optimize integer-to-string conversion in vsprintf.c for base 10.  This is
by far the most used conversion, and in some use cases it impacts
performance.  For example, top reads /proc/$PID/stat for every process, and
with 4000 processes decimal conversion alone takes noticeable time.

Using code from

http://www.cs.uiowa.edu/~jones/bcd/decimal.html
(with permission from the author, Douglas W. Jones)

binary-to-decimal-string conversion is done in groups of five digits at
once, using only additions/subtractions/shifts (with -O2; -Os throws in
some multiply instructions).

On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code.

This patch is run tested. Userspace benchmark/test is also attached.
I tested it on PIII and AMD64 and new code is generally ~2.5 times
faster. On AMD64:

# ./vsprintf_verify-O2
Original decimal conv: .......... 151 ns per iteration
Patched decimal conv:  .......... 62 ns per iteration
Testing correctness
12895992590592 ok...        [Ctrl-C]
# ./vsprintf_verify-O2
Original decimal conv: .......... 151 ns per iteration
Patched decimal conv:  .......... 62 ns per iteration
Testing correctness
26025406464 ok...        [Ctrl-C]

More realistic test: top from busybox project was modified to
report how many us it took to scan /proc (this does not account
any processing done after that, like sorting process list),
and then I test it with 4000 processes:

#!/bin/sh
i=4000
while test $i != 0; do
    sleep 30 &
    let i--
done
busybox top -b -n3 >/dev/null

on unpatched kernel:

top: 4120 processes took 102864 microseconds to scan
top: 4120 processes took 91757 microseconds to scan
top: 4120 processes took 92517 microseconds to scan
top: 4120 processes took 92581 microseconds to scan

on patched kernel:

top: 4120 processes took 75460 microseconds to scan
top: 4120 processes took 66451 microseconds to scan
top: 4120 processes took 67267 microseconds to scan
top: 4120 processes took 67618 microseconds to scan

The speedup comes from much faster generation of /proc/PID/stat
by sprintf() calls inside the kernel.

Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:52 -07:00
Denis Vlasenko
b39a734097 vsprintf.c: optimizing, part 1 (easy and obvious stuff)
* There is no point in having full "0...9a...z" constant vector,
  if we use only "0...9a...f" (and "x" for "0x").

* Post-decrement usually needs a few more instructions, so use
  pre decrement instead where makes sense:
-       while (i < precision--) {
+       while (i <= --precision) {

* if base != 10 (=> base 8 or 16), we can avoid using division
  in a loop and use mask/shift, obtaining much faster conversion.
  (More complex optimization for base 10 case is in the second patch).

Overall, size vsprintf.o shows ~80 bytes smaller text section
with this patch applied.

Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:52 -07:00
Johannes Berg
c6b40d16d1 fix sscanf %n match at end of input string
I was playing with some code that sometimes got a string where a %n
match should have been done where the input string ended, for example
like this:

  sscanf("abc123", "abc%d%n", &a, &n);  /* doesn't work */
  sscanf("abc123a", "abc%d%n", &a, &n); /* works */

However, the scanf function in the kernel doesn't convert the %n in that
case because it has already matched the complete input after %d and just
completely stops matching then. This patch fixes that.

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:05 -07:00
Jeremy Fitzhardinge
11443ec7d9 Add kvasprintf()
Add a kvasprintf() function to complement kasprintf().

No in-tree users yet, but I have some coming up.

[akpm@linux-foundation.org: EXPORT it]
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Keir Fraser <keir@xensource.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-04-30 16:40:40 -07:00
Martin Peschke
ea6f3281a1 [PATCH] scnprintf(): fix a comment
The return value of scnprintf() never exceeds @size.

Signed-off-by: Martin Peschke <mp3@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:28 -08:00
Robert P. J. Day
72fd4a35a8 [PATCH] Numerous fixes to kernel-doc info in source files.
A variety of (mostly) innocuous fixes to the embedded kernel-doc content in
source files, including:

  * make multi-line initial descriptions single line
  * denote some function names, constants and structs as such
  * change erroneous opening '/*' to '/**' in a few places
  * reword some text for clarity

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:32 -08:00
Linus Torvalds
0a6047eef1 Fix vsnprintf off-by-one bug
The recent vsnprintf() fix introduced an off-by-one, and it's now
possible to overrun the target buffer by one byte.

The "end" pointer points to past the end of the buffer, so if we
have to truncate the result, it needs to be done though "end[-1]".

[ This is just an alternate and simpler patch to one proposed by Andrew
  and Jeremy, who actually noticed the problem ]

Acked-by: Andrew Morton <akpm@osdl.org>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-28 17:09:34 -07:00
Jeremy Fitzhardinge
e905914f96 [PATCH] Implement kasprintf
Implement kasprintf, a kernel version of asprintf.  This allocates the
memory required for the formatted string, including the trailing '\0'.
Returns NULL on allocation failure.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-25 10:01:23 -07:00
Jeremy Fitzhardinge
f796937a06 [PATCH] Fix bounds check in vsnprintf, to allow for a 0 size and NULL buffer
This change allows callers to use a 0-byte buffer and a NULL buffer pointer
with vsnprintf, so it can be used to determine how large the resulting
formatted string will be.

Previously the code effectively treated a size of 0 as a size of 4G (on
32-bit systems), with other checks preventing it from actually trying to
emit the string - but the terminal \0 would still be written, which would
crash if the buffer is NULL.

This change changes the boundary check so that 'end' points to the putative
location of the terminal '\0', which is only written if size > 0.

vsnprintf still allows the buffer size to be set very large, to allow
unbounded buffer sizes (to implement sprintf, etc).

[akpm@osdl.org: fix long-vs-longlong confusion]
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-25 10:01:23 -07:00
Tim Schmielau
4e57b68178 [PATCH] fix missing includes
I recently picked up my older work to remove unnecessary #includes of
sched.h, starting from a patch by Dave Jones to not include sched.h
from module.h. This reduces the number of indirect includes of sched.h
by ~300. Another ~400 pointless direct includes can be removed after
this disentangling (patch to follow later).
However, quite a few indirect includes need to be fixed up for this.

In order to feed the patches through -mm with as little disturbance as
possible, I've split out the fixes I accumulated up to now (complete for
i386 and x86_64, more archs to follow later) and post them before the real
patch.  This way this large part of the patch is kept simple with only
adding #includes, and all hunks are independent of each other.  So if any
hunk rejects or gets in the way of other patches, just drop it.  My scripts
will pick it up again in the next round.

Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:32 -08:00
Al Viro
8032230694 [PATCH] %t... in vsnprintf
handling of %t... (ptrdiff_t) in vsnprintf

Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-23 18:43:46 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00