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Code Issues Releases Wiki Activity

vsprintf: uninline simple_strntoull(), reorder arguments 

* uninline simple_strntoull(),
  gcc overinlines and this function is not performance critical

* reorder arguments, so that appending INT_MAX as 4th argument
  generates very efficient tail call

Space savings:

	add/remove: 1/0 grow/shrink: 0/3 up/down: 27/-179 (-152)
	Function                            old     new   delta
	simple_strntoll                       -      27     +27
	simple_strtoull                      15      10      -5
	simple_strtoll                       41       7     -34
	vsscanf                            1930    1790    -140

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/all/82a2af6e-9b6c-4a09-89d7-ca90cc1cdad1@p183/
This commit is contained in:
Alexey Dobriyan 2023-10-27 17:13:58 +03:00 committed by Petr Mladek
parent 3f6074cf46
commit 72fcce70fa
1 changed files with 12 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
lib/vsprintf.c
View File

@ -60,7 +60,8 @@
bool no_hash_pointers __ro_after_init;
EXPORT_SYMBOL_GPL(no_hash_pointers);
static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base)
noinline
static unsigned long long simple_strntoull(const char *startp, char **endp, unsigned int base, size_t max_chars)
{
const char *cp;
unsigned long long result = 0ULL;
@ -95,7 +96,7 @@ static noinline unsigned long long simple_strntoull(const char *startp, size_t m
noinline
unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
{
return simple_strntoull(cp, INT_MAX, endp, base);
return simple_strntoull(cp, endp, base, INT_MAX);
}
EXPORT_SYMBOL(simple_strtoull);
@ -130,8 +131,8 @@ long simple_strtol(const char *cp, char **endp, unsigned int base)
}
EXPORT_SYMBOL(simple_strtol);
static long long simple_strntoll(const char *cp, size_t max_chars, char **endp,
unsigned int base)
noinline
static long long simple_strntoll(const char *cp, char **endp, unsigned int base, size_t max_chars)
{
/*
* simple_strntoull() safely handles receiving max_chars==0 in the
@ -140,9 +141,9 @@ static long long simple_strntoll(const char *cp, size_t max_chars, char **endp,
* and the content of *cp is irrelevant.
*/
if (*cp == '-' && max_chars > 0)
return -simple_strntoull(cp + 1, max_chars - 1, endp, base);
return -simple_strntoull(cp + 1, endp, base, max_chars - 1);
return simple_strntoull(cp, max_chars, endp, base);
return simple_strntoull(cp, endp, base, max_chars);
}
/**
@ -155,7 +156,7 @@ static long long simple_strntoll(const char *cp, size_t max_chars, char **endp,
*/
long long simple_strtoll(const char *cp, char **endp, unsigned int base)
{
return simple_strntoll(cp, INT_MAX, endp, base);
return simple_strntoll(cp, endp, base, INT_MAX);
}
EXPORT_SYMBOL(simple_strtoll);
@ -3648,13 +3649,11 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
break;
if (is_sign)
val.s = simple_strntoll(str,
field_width >= 0 ? field_width : INT_MAX,
&next, base);
val.s = simple_strntoll(str, &next, base,
field_width >= 0 ? field_width : INT_MAX);
else
val.u = simple_strntoull(str,
field_width >= 0 ? field_width : INT_MAX,
&next, base);
val.u = simple_strntoull(str, &next, base,
field_width >= 0 ? field_width : INT_MAX);
switch (qualifier) {
case 'H': /* that's 'hh' in format */