On Tue, 13 Nov 2007, Joe Perches wrote:
>
> Remove defconfig ptr comparison to 0
>
> The memcpy from memory location 0 sure looks odd.
Btw, this is also very compiler-bug-prone.
And sadly, the cast to "(void *)" doesn't help. This could easily be a
case where a compiler decides to play lawyer games, knowing that "NULL
pointers cannot be dereferenced", deciding that it's all totally undefined
behavior, and then just "optimizing" it all away.
> - memcpy(&header, 0, sizeof(struct acpi_table_header));
> + memcpy(&header, (void *)0, sizeof(struct acpi_table_header));
So to be safe from bogus compilers who care more about standards than the
obvious intention of the programmer, it might actually be better in the
long run to do something like
static inline void *create_pointer(unsigned long val)
{
void *result;
asm("":"=r" (result):"0" (val));
return result;
}
and then use "create_pointer(0)" here.
On that note: I'm not going to apply this series, because it's simply not
really appropriate any more. But when re-sending for 2.6.25-rc1, can you
make the subject lines have a slightly higher signal-to-noise ratio, ie
dropt he unnecessary stuff that doesn't add any value as a commit message
(eg "defconfig"? Is it really relevant?), and make it properly formatted?
My scripts by default remove the stuff in between []'s, so the end result
for the commit message header from this subject line would be
"- remove defconfig ptr comparisons to 0 - include/asm-x86"
which is strange and not very useful. It would read better as
Subject: [PATCH 1/15] include/asm-x86: remove ptr comparisons to 0
which would create a commit message header that is more readable.
Linus
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