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checkpatch: fix multi-statement macro checks for while blocks.

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Checkpatch.pl doesn't have a check for excluding while (...) {...} blocks
from MULTISTATEMENT_MACRO_USE_DO_WHILE error.

For example, running checkpatch.pl on the file mm/maccess.c in the kernel
generates the following error:

ERROR: Macros with complex values should be enclosed in parentheses
+#define copy_from_kernel_nofault_loop(dst, src, len, type, err_label)  \
+       while (len >= sizeof(type)) {                                   \
+               __get_kernel_nofault(dst, src, type, err_label);        \
+               dst += sizeof(type);                                    \
+               src += sizeof(type);                                    \
+               len -= sizeof(type);                                    \
+       }

The error is misleading for this case.  Enclosing it in parentheses
doesn't make any sense.

Checkpatch already has an exception list for such common macro types.
Added a new exception for while (...) {...} style blocks to the same.

In addition, the brace flatten logic was modified by changing the
substitution characters from "1" to "1u".  This was done to ensure that
macros in the form "#define foo(bar) while(bar){bar--;}" were also
correctly procecssed.

Link: https://lore.kernel.org/linux-kernel-mentees/dc985938aa3986702815a0bd68dfca8a03c85447.camel@perches.com/

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20201001171903.312021-1-dwaipayanray1@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dwaipayan Ray 2020-10-15 20:12:22 -07:00 committed by Linus Torvalds
parent a0154cdbd3
commit 2e44e8033a
1 changed files with 4 additions and 3 deletions
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7
scripts/checkpatch.pl
View file

@ -5351,9 +5351,9 @@ sub process {
$dstat =~ s/\s*$//s;
# Flatten any parentheses and braces
while ($dstat =~ s/\([^\(\)]*\)/1/ ||
$dstat =~ s/\{[^\{\}]*\}/1/ ||
$dstat =~ s/.\[[^\[\]]*\]/1/)
while ($dstat =~ s/\([^\(\)]*\)/1u/ ||
$dstat =~ s/\{[^\{\}]*\}/1u/ ||
$dstat =~ s/.\[[^\[\]]*\]/1u/)
{
}
@ -5394,6 +5394,7 @@ sub process {
$dstat !~ /^\.$Ident\s*=/ && # .foo =
$dstat !~ /^(?:\#\s*$Ident|\#\s*$Constant)\s*$/ && # stringification #foo
$dstat !~ /^do\s*$Constant\s*while\s*$Constant;?$/ && # do {...} while (...); // do {...} while (...)
$dstat !~ /^while\s*$Constant\s*$Constant\s*$/ && # while (...) {...}
$dstat !~ /^for\s*$Constant$/ && # for (...)
$dstat !~ /^for\s*$Constant\s+(?:$Ident|-?$Constant)$/ && # for (...) bar()
$dstat !~ /^do\s*{/ && # do {...