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Commit 43c1d77c authored by Joe Perches's avatar Joe Perches Committed by Linus Torvalds
Browse files

checkpatch: add test for long udelay 



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: default avatarJoe Perches <joe@perches.com>
Reported-by: default avatarHolger Schurig <holgerschurig@gmail.com>
Cc: Sujith Manoharan <sujith@msujith.org>
Cc: John Linville <linville@tuxdriver.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent af661e83

scripts/checkpatch.pl

+8 −3
Original line number Diff line number Diff line
@@ -3912,10 +3912,15 @@ sub process { 


# prefer usleep_range over udelay

		if ($line =~ /\budelay\s*\(\s*(\d+)\s*\)/) {

			my $delay = $1;

			# ignore udelay's < 10, however

			if (! ($1 < 10) ) {

			if (! ($delay < 10) ) {

				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 ($1 < 20) {

				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);

			}

		}