There appears to be no reason for the tmp_cmdline array to be
qualified as "static __initdata" since its value is apparently gone
once this routine ends.
Compile- and boot-time tested on i386.
Signed-off-by: Robert P. J. Day <rpjday@xxxxxxxxxxxxxx>
---
(i'm willing to be corrected on this one.)
there's a bit of a story behind this. as i was following the logic
for defining and processing kernel boot-time parameters, i was baffled
as to why that array was declared with "static __initdata", as if it
needed to retain its contents after the function returned.
since parse_early_param() defines a static "done" variable that
guarantees that it can only ever be run once, there seemed to be no
point in retaining that copy of the command line once the command-line
parameters were processed.
if you follow the logic, you eventually work your way down to the
routine do_early_param() which, given a parameter name and its value
(both strings), simply invokes:
...
if (p->setup_func(val) != 0)
printk(KERN_WARNING "Malformed early option '%s'\n", param);
...
which inspires the obvious question -- when a kernel parameter setup
routine is called, is it allowed to assume that the data at the value
address it's passed will remain *even after it returns*? if not, then
it would seem that there is no reason for that "static __initdata".
on the other hand, if any one of those setup routines *is* making
that assumption, then dropping that qualifier will definitely cause
bad things to happen somewhere down the road at some point in the boot
process.
it seems like a trivial patch until you appreciate the possible
implications for all of those kernel parm setup routines defined in
all those calls to __setup() and early_param(). in essence, by
applying that patch, you'll find out who's cheating.
thoughts?
p.s. also, if it's not required, declaring it as "static __initdata"
is seriously confusing, since it gives the obvious impression that the
contents *need* to be retained, which just makes following the logic
that much harder if you're working under that misimpression.
diff --git a/init/main.c b/init/main.c
index 9def935..86d2ffc 100644
--- a/init/main.c
+++ b/init/main.c
@@ -482,7 +482,7 @@ static int __init do_early_param(char *param, char *val)
void __init parse_early_param(void)
{
static __initdata int done = 0;
- static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
+ char tmp_cmdline[COMMAND_LINE_SIZE];
if (done)
return;
--
========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry
Waterloo, Ontario, CANADA
http://crashcourse.ca
========================================================================
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