On Sat, 2013-10-12 at 19:05 +0100, Krzysztof Mazur wrote: > Before commit 026cee0086fe1df4cf74691cf273062cc769617d > ("params: <level>_initcall-like kernel parameters") the __setup > parameter parsing code could modify parameter in the > static_command_line buffer and such modifications were kept. After > that commit such modifications are destroyed during per-initcall level > parameter parsing because the same static_command_line buffer is used > and only parameters for appropriate initcall level are parsed. > > That change broke at least parsing "ubd" parameter in the ubd driver > when the COW file is used. > > Now the separate buffer is used for per-initcall parameter parsing, > like in parsing early params. > > Signed-off-by: Krzysztof Mazur <krzys...@podlesie.net> > --- > > init/main.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/init/main.c b/init/main.c > index 63d3e8f..e5b322a 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -742,12 +742,13 @@ static char *initcall_level_names[] __initdata = { > > static void __init do_initcall_level(int level) > { > + static __initdata char tmp_cmdline[COMMAND_LINE_SIZE]; > extern const struct kernel_param __start___param[], __stop___param[]; > initcall_t *fn; > > - strcpy(static_command_line, saved_command_line); > + strcpy(tmp_cmdline, saved_command_line); > parse_args(initcall_level_names[level], > - static_command_line, __start___param, > + tmp_cmdline, __start___param, > __stop___param - __start___param, > level, level, > &repair_env_string);
Hold on. static_command_line can be only accessed within init/main.c. As far as I can say, it is only used by unknown_bootoption() (so your __setup callbacks) and then in the do_initcall_level(). So, assuming that it is actually legal to modify static_command_line in __setup()-s (and I must say I have rather mixed feelings about it ;-), the only place that will be able to make use of this changes will be do_initcall_level(). But your change actually uses *saved*_command_line instead of *static*_command_line as the base for parse_args. Generally I agree that the commit in question changed the semantics in a subtle way - it makes the do_initcalls() use saved_command_line as a string to be parsed instead of static_command_line. I was convinced that at this stage of execution they must be identical (and the static_command_line is a de-facto scratch buffer). You're saying that is may not be the case, which can be true, but you're keeping the same behaviour :-) So either you have some extra changes in your kernel actually using static_command_line for some other reason, or your change makes no difference. The third option is me being brain dead today, which is not impossible ;-) Paweł -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/