| Message ID | 1464984122-16381-1-git-send-email-nm@ti.com |
|---|---|
| State | New |
| Headers | show |
On 06/03/2016 03:42 PM, Joe Perches wrote: > On Fri, 2016-06-03 at 15:02 -0500, Nishanth Menon wrote: >> In some functions, returning a -ve decimal value is actually a valid >> return condition when the function is returning a value, however, it >> can also be misused for returning an error value that should ideally >> be a valid error code defined in include/uapi/asm-generic/errno-base.h >> or include/uapi/asm-generic/errno.h. The notable exception is "-1" >> which has quiet a history of usage as pointed out by Joe Perches. >> >> Considering typical error of doing the following: >> int fn(void) >> { >> /* ... error condition ... */ >> return -2; >> } >> >> void fn1(void) >> { >> /* some code */ >> if (fn() < 0) { >> pr_err("Error occurred\n"); >> return; >> } >> /* other cases... */ >> } >> >> Flag this as a check case for developer verification. >> >> The check is done for negative values less than 1 and tools >> directory is exempt from this requirement based on Joe Perches' >> suggestion. >> >> Suggested-by: Joe Perches <joe@perches.com> > > No, I didn't suggest this. Sorry, I had hoped to give you credit for the recommended regex optimization and recommendations you gave. > I'm not at all sure it's even a good idea. OK. I can drop this if we'd not want to go down this road. we can catch stuff in review as much as possible, I was hoping we can catch the easy ones by forcing a relook by developers. > >> Signed-off-by: Nishanth Menon <nm@ti.com> >> --- >> Changes in V2: >> - change in regex for check for check for less than 1 >> - Update in commit message to the effect >> - Added Suggested-by for Joe's recommendation on regex. >> >> V1: https://patchwork.kernel.org/patch/9153345/ >> >> scripts/checkpatch.pl | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl >> index 4904ced676d4..a2e677b5fd78 100755 >> --- a/scripts/checkpatch.pl >> +++ b/scripts/checkpatch.pl >> @@ -4351,6 +4351,12 @@ sub process { >> } >> } >> >> +# return with a value is not usually a good sign, unless the function is supposed to return a value >> + if ($realfile !~ /^tools/ && defined($stat) && $stat =~ /^.\s*return\s*-\s*(?!1\b)\d+\s*;/s) { > > I think > if ($realfile != /^tools/ && $line =~ /\breturn\s*-\s*(?!1\b)\d+\s*;/ > would be better as it would catch return -2 in a macro or a > multi-line statement like > if (<foo>) return -2; > Nice. >> + CHK("RETURN_NUMBER", >> + "Suspect error return with a value, If this is error value, refer to include/uapi/asm-generic/errno-base.h and include/uapi/asm-generic/errno.h\n" . $herecurr); > > That's an awfully long message. > > Maybe something like: > "Perhaps better to use standard ERRNO system error symbols" > Fair enough. Will hold off a respin based on direction we would like to take. -- Regards, Nishanth Menon
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 4904ced676d4..a2e677b5fd78 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -4351,6 +4351,12 @@ sub process { } } +# return with a value is not usually a good sign, unless the function is supposed to return a value + if ($realfile !~ /^tools/ && defined($stat) && $stat =~ /^.\s*return\s*-\s*(?!1\b)\d+\s*;/s) { + CHK("RETURN_NUMBER", + "Suspect error return with a value, If this is error value, refer to include/uapi/asm-generic/errno-base.h and include/uapi/asm-generic/errno.h\n" . $herecurr); + } + # unnecessary return in a void function # at end-of-function, with the previous line a single leading tab, then return; # and the line before that not a goto label target like "out:"
In some functions, returning a -ve decimal value is actually a valid return condition when the function is returning a value, however, it can also be misused for returning an error value that should ideally be a valid error code defined in include/uapi/asm-generic/errno-base.h or include/uapi/asm-generic/errno.h. The notable exception is "-1" which has quiet a history of usage as pointed out by Joe Perches. Considering typical error of doing the following: int fn(void) { /* ... error condition ... */ return -2; } void fn1(void) { /* some code */ if (fn() < 0) { pr_err("Error occurred\n"); return; } /* other cases... */ } Flag this as a check case for developer verification. The check is done for negative values less than 1 and tools directory is exempt from this requirement based on Joe Perches' suggestion. Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Nishanth Menon <nm@ti.com> --- Changes in V2: - change in regex for check for check for less than 1 - Update in commit message to the effect - Added Suggested-by for Joe's recommendation on regex. V1: https://patchwork.kernel.org/patch/9153345/ scripts/checkpatch.pl | 6 ++++++ 1 file changed, 6 insertions(+) -- 2.8.0