linux-kernel - [PATCH] checkpatch: Check for %L for all integer formats (was: Re: [PATCH] fix printk format compiler warnings)

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Date:	Tue, 30 Sep 2008 13:29:44 +0200 (CEST)
From:	Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com>
To:	Jan Beulich <jbeulich@...ell.com>,
	Andy Whitcroft <apw@...dowen.org>,
	Randy Dunlap <rdunlap@...otime.net>,
	Joel Schopp <jschopp@...tin.ibm.com>
cc:	Linux Kernel Development <linux-kernel@...r.kernel.org>
Subject: [PATCH] checkpatch: Check for %L for all integer formats (was: Re:
 [PATCH] fix printk format compiler warnings)

On Fri, 5 Sep 2008, Jan Beulich wrote:
> %llx and the like cannot be used on u64-derived data types - they must
> be cast to long long explicitly for arch-es where u64 is a typedef of
> unsigned long (ia64 is where I observed the problem).

> -		printk(KERN_INFO "PCI: bridge %s io port: [%llx, %llx]\n", pci_name(dev), res->start, res->end);
> +		printk(KERN_INFO "PCI: bridge %s io port: [%Lx, %Lx]\n",

> -		printk(KERN_INFO "PCI: bridge %s 32bit mmio: [%llx, %llx]\n", pci_name(dev), res->start, res->end);
> +		printk(KERN_INFO "PCI: bridge %s 32bit mmio: [%Lx, %Lx]\n",

> -		printk(KERN_INFO "PCI: bridge %s %sbit mmio pref: [%llx, %llx]\n", pci_name(dev), (res->flags & PCI_PREF_RANGE_TYPE_64)?"64":"32",res->start, res->end);
> +		printk(KERN_INFO "PCI: bridge %s %dbit mmio pref: [%Lx, %Lx]\n",

> -		printk(KERN_INFO "bus: %02x index %x %s: [%llx, %llx]\n", bus->number, i, (res->flags & IORESOURCE_IO)? "io port":"mmio", res->start, res->end);
> +		printk(KERN_INFO "bus: %02x index %x %s: [%Lx, %Lx]\n",

Why did you replace `%ll' by `%L'?

While `L' is used as an internal flag in Linux' vsnprintf() implementation and
is still supported because of historical (pre-C99) reasons, the `L' conversion
qualifier is meant for the `long double' floating point type, as per C99.
The recommended conversion qualifier for the `long long' integer type is `ll'.

Perhaps checkpatch should check for this? Ah, it already does for some of the
integer formats. The patch below adds checks for the missing ones.

Subject: [PATCH] checkpatch: Check for %L for all integer formats

Checkpatch checks for the use of the non-standard `L' conversion qualifier for
some (`u', `d', and `i') of the 6 integers formats.  Add the missing ones
(`o', `x', and `X'), and keep the list sorted.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index bc67793..92cbf5e 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2277,12 +2277,12 @@ sub process {
 			WARN("usage of NR_CPUS is often wrong - consider using cpu_possible(), num_possible_cpus(), for_each_possible_cpu(), etc\n" . $herecurr);
 		}
 
-# check for %L{u,d,i} in strings
+# check for %L{d,i,o,u,x,X} in strings
 		my $string;
 		while ($line =~ /(?:^|")([X\t]*)(?:"|$)/g) {
 			$string = substr($rawline, $-[1], $+[1] - $-[1]);
-			if ($string =~ /(?<!%)%L[udi]/) {
-				WARN("\%Ld/%Lu are not-standard C, use %lld/%llu\n" . $herecurr);
+			if ($string =~ /(?<!%)%L[diouxX]/) {
+				WARN("\%L[diouxX] are not-standard C, use %ll[diouxX]\n" . $herecurr);
 				last;
 			}
 		}


With kind regards,

Geert Uytterhoeven
Software Architect

Sony Techsoft Centre Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium

Phone:    +32 (0)2 700 8453
Fax:      +32 (0)2 700 8622
E-mail:   Geert.Uytterhoeven@...ycom.com
Internet: http://www.sony-europe.com/

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