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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2013-04-19 17:10:27 -0400
committerSteven Rostedt <rostedt@goodmis.org>2013-04-19 17:10:27 -0400
commitd2802d0739dcc61af5e5ea00773ce7ddead4e9c2 (patch)
tree29d27970f8830dabeea7647479cc4bf9adda5929 /include/linux/ftrace_event.h
parentc192c8356cc878cfa98ebd3056478674786c0a4d (diff)
downloadop-kernel-dev-d2802d0739dcc61af5e5ea00773ce7ddead4e9c2.zip
op-kernel-dev-d2802d0739dcc61af5e5ea00773ce7ddead4e9c2.tar.gz
tracing: Compare to 1 instead of zero for is_signed_type()
The formats of the trace events show if the type of a event field is signed or not via a macro called is_signed_type(). This does a trick with the type and compares a -1 to zero after typecasting to the tested type. If it returns true, it's signed, otherwise its not. But this unfortunately triggers a warning by gcc: warning: comparison of unsigned expression < 0 is always false As we know it is always false (that's why we do it), this is a false warning. Luckily for us, the comparison works with a 1 as well, without giving the warning. Convert the check to compare (type)-1 < (type)0 to (type)-1 < (type)1 to determine if the type is signed or not. Link: http://lkml.kernel.org/r/CAErSpo4YXcY9fuOKWYGDkddJwk68kmZTohsmVB6QvrhjboOh1Q@mail.gmail.com Reported-by: Bjorn Helgaas <bhelgaas@google.com> Reported-by: Gary Hade <garyhade@us.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/ftrace_event.h')
-rw-r--r--include/linux/ftrace_event.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 4e28b01..34e00fb 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -333,7 +333,7 @@ extern int trace_define_field(struct ftrace_event_call *call, const char *type,
extern int trace_add_event_call(struct ftrace_event_call *call);
extern void trace_remove_event_call(struct ftrace_event_call *call);
-#define is_signed_type(type) (((type)(-1)) < (type)0)
+#define is_signed_type(type) (((type)(-1)) < (type)1)
int trace_set_clr_event(const char *system, const char *event, int set);
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