On Friday 05 June 2009 20:50:48 John W. Linville wrote: > On Fri, Jun 05, 2009 at 07:29:07PM +0200, Michael Buesch wrote: > > On Friday 05 June 2009 14:25:03 John W. Linville wrote: > > > On Thu, Jun 04, 2009 at 11:18:33PM +0200, Michael Buesch wrote: > > > > From: Matthieu CASTET <[email protected]> > > > > > > > > Fix possible unaligned u32 access in b43_generate_plcp_hdr(). > > > > Unaligned data is read/write with a u32 pointer instead of using the > > > > packed structure. Some versions of gcc ignore the "packed" attribute, > > > > if the > > > > structure element is accessed through a local pointer. > > > > > > > > Signed-off-by: Matthieu CASTET <[email protected]> > > > > Signed-off-by: Michael Buesch <[email protected]> > > > > > > That seems pretty brain-dead...can you cite a source for this > > > information? The patch seems like a no-op... > > > > > > John > > > > struct foo { > > int data; > > } __attribute__((packed)); > > > > struct foo foo; > > int *d = &foo->data; > > foo->data = x; /* Works for unaligned */ > > *d = y; /* Does not work for unaligned */ > > Why not? >
Because some compilers don't carry the "packed" attribute of "data" though the "d" pointer. So foo->data is a "packed" access, while *d might not. -- Greetings, Michael. _______________________________________________ Bcm43xx-dev mailing list [email protected] https://lists.berlios.de/mailman/listinfo/bcm43xx-dev
