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checkpatch: add test for long udelay

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Holger reported:

: The macro udelay cannot handle large values because of loss-of-precision.
:
: IMHO udelay on ARM is broken, because it also cannot work with fast
: ARM processors (where bogomips >= 3355, which is in sight now). It's
: just not broken enough that someone did something against it ...   so
: the current kludge is good enough.

Until then, warn on long udelay uses.

Also fix uses of $line that should have been $herecurr.

Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Holger Schurig <holgerschurig@gmail.com>
Cc: Sujith Manoharan <sujith@msujith.org>
Cc: John Linville <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joe Perches 2014-04-03 14:49:11 -07:00 • committed by Linus Torvalds
parent af661e8360
commit 43c1d77c39
1 changed files with 8 additions and 3 deletions
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11
scripts/checkpatch.pl
View file

@ -3912,10 +3912,15 @@ sub process {
# prefer usleep_range over udelay # prefer usleep_range over udelay
if ($line =~ /\budelay\s*\(\s*(\d+)\s*\)/) { if ($line =~ /\budelay\s*\(\s*(\d+)\s*\)/) {
my $delay = $1;
# ignore udelay's < 10, however # ignore udelay's < 10, however
if (! ($1 < 10) ) { if (! ($delay < 10) ) {
CHK("USLEEP_RANGE", CHK("USLEEP_RANGE",
"usleep_range is preferred over udelay; see Documentation/timers/timers-howto.txt\n" . $line); "usleep_range is preferred over udelay; see Documentation/timers/timers-howto.txt\n" . $herecurr);
}
if ($delay > 2000) {
WARN("LONG_UDELAY",
"long udelay - prefer mdelay; see arch/arm/include/asm/delay.h\n" . $herecurr);
} }
} }
@ -3923,7 +3928,7 @@ sub process {
if ($line =~ /\bmsleep\s*\((\d+)\);/) { if ($line =~ /\bmsleep\s*\((\d+)\);/) {
if ($1 < 20) { if ($1 < 20) {
WARN("MSLEEP", WARN("MSLEEP",
"msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt\n" . $line); "msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt\n" . $herecurr);
} }
} }