Commit de3f186f authored Sep 25, 2019 by Denis Efremov Committed by Linus Torvalds Sep 25, 2019

checkpatch: check for nested (un)?likely() calls

IS_ERR(), IS_ERR_OR_NULL(), IS_ERR_VALUE() and WARN*() already contain
unlikely() optimization internally.  Thus, there is no point in calling
these functions and defines under likely()/unlikely().

This check is based on the coccinelle rule developed by Enrico Weigelt
https://lore.kernel.org/lkml/1559767582-11081-1-git-send-email-info@metux.net/

Link: http://lkml.kernel.org/r/20190829165025.15750-1-efremov@linux.com


Signed-off-by: Denis Efremov <efremov@linux.com>
Cc: Joe Perches <joe@perches.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Anton Altaparmakov <anton@tuxera.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Boris Pismenny <borisp@mellanox.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Denis Efremov <efremov@linux.com>
Cc: Dennis Dalessandro <dennis.dalessandro@intel.com>
Cc: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Mike Marciniszyn <mike.marciniszyn@intel.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Sean Paul <sean@poorly.run>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent c7cc8d77

scripts/checkpatch.pl

+6 −0

Original line number	Diff line number	Diff line
		@@ -6507,6 +6507,12 @@ sub process {
		"Using $1 should generally have parentheses around the comparison\n" . $herecurr);
		}

		# nested likely/unlikely calls
		if ($line =~ /\b(?:(?:un)?likely)\s\(\s!?\s*(IS_ERR(?:_OR_NULL\|_VALUE)?\|WARN)/) {
		WARN("LIKELY_MISUSE",
		"nested (un)?likely() calls, $1 already uses unlikely() internally\n" . $herecurr);
		}

		# whine mightly about in_atomic
		if ($line =~ /\bin_atomic\s*\(/) {
		if ($realfile =~ m@^drivers/@) {

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