In kernel/params.c::module_attr_show and kernel/params.c::module_attr_store we call to_module_kobject() and save the result in a local variable right before a conditional statement that does not depend on the call to to_module_kobject() and may cause the function to return. If the function returns before we use the result of to_module_kobject() then the call is just a waste of time. The patch moves the call to to_module_kobject() down just before it is actually used, thus we save a call to the function in a few cases. I doubt this is in any way measurable, but I see no reason to not move the call - it should be an infinitesimal improvement with no ill sideeffects.
Please consider applying.
Signed-off-by: Jesper Juhl <[EMAIL PROTECTED]>
diff -up linux-2.6.11-rc2-bk7-orig/kernel/params.c linux-2.6.11-rc2-bk7/kernel/params.c
--- linux-2.6.11-rc2-bk7-orig/kernel/params.c 2005-01-29 23:54:53.000000000 +0100
+++ linux-2.6.11-rc2-bk7/kernel/params.c 2005-01-30 00:27:08.000000000 +0100
@@ -625,11 +625,12 @@ static ssize_t module_attr_show(struct k
int ret;
attribute = to_module_attr(attr);
- mk = to_module_kobject(kobj);
if (!attribute->show)
return -EPERM;
+ mk = to_module_kobject(kobj);
+
if (!try_module_get(mk->mod))
return -ENODEV;
@@ -649,11 +650,12 @@ static ssize_t module_attr_store(struct int ret;
attribute = to_module_attr(attr);
- mk = to_module_kobject(kobj);
if (!attribute->store)
return -EPERM;
+ mk = to_module_kobject(kobj);
+
if (!try_module_get(mk->mod))
return -ENODEV;
I'd bet that the compiler already reorders the assignment since there is no side effect to to_module_kobject(). Even with a patch like this you can't control exactly when the assignment is done. There may not even be an assignment, since mk is a constant offset of kobj.
--
Brian Gerst
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