Re: [Crash-utility] [PATCH] Remove the VOID_PTR facilitator macro

Dne čtvrtek 27 Leden 2011 19:47:41 Dave Anderson napsal(a): > ----- Original Message ----- > > > Hi Dave, > > > > > BTW, was there a reason that you changed this?: > > > if (si->c_flags & SLAB_CFLGS_BUFCTL) > > > > > > - obj = si->s_mem + ((next - si->s_index) * si->c_offset); > > > + obj = si->s_mem + (next - si->s_index) * si->c_offset; > > > > It wasn't my patch so I'm only offering my ACK for the original change > > and my reason is that multiply has higher operator precedence than add > > (and subtract) in normal arithmetic so the outer parentheses were > > never necessary anyway. They didn't create an error but they weren't > > needed either. The inner parentheses are required. > > > > -- > > David Mair. > > Right I understand that, but the sources are full of such > "extra" parentheses, some to prevent compiler warnings, but > mostly just for ease of maintainability/understanding. > > I just was wondering why that line was explicitly changed. No reason, except I removed them for some reason while developing the patch and forgot to put them back afterwards. I can leave it as-is. Oh, I've just realized that this actually changed the expression, because originally both variables were pointers to ulong, so (next - si->s_index) should become ((next - si->s_index)/sizeof(ulong)) I wonder whether this was originally intended. Let me have one more look at this.