On Mon, Jul 9, 2018 at 7:49 AM Greg KH greg@kroah.com wrote:
On Mon, Jul 09, 2018 at 07:44:44AM +0300, Alexey Brodkin wrote:
Depending on ABI "long long" type of a particular 32-bit CPU might be aligned by either word (32-bits) or double word (64-bits).
Or even 16-bit (on e.g. m68k).
--- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -24,8 +24,12 @@ struct devres_node {
struct devres { struct devres_node node;
/* -- 3 pointers */unsigned long long data[]; /* guarantee ull alignment */
/** Depending on ABI "long long" type of a particular 32-bit CPU* might be aligned by either word (32-bits) or double word (64-bits).
or even 16-bit (on e.g. m68k).
* Make sure "data" is really 64-bit aligned for any 32-bit CPU.*/unsigned long long data[] __aligned(sizeof(unsigned long long));};
Does this change the padding today for any other arches? If so, does the increased memory usage cause any noticable issues?
Yes it does. struct devres_node contains an odd number of pointers, so there will be a hole between node and data on all 32-bit architectures.
Gr{oetje,eeting}s,
Geert