On Thu, May 22 2025, Tom Rini <[email protected]> wrote: > On Wed, May 07, 2025 at 02:12:42PM +0200, Rasmus Villemoes wrote: > >> While looking through list.h, I saw that the regular list_* helpers >> (and one of the hlist_* ones) still contain the prefetch() that was >> removed in linux 14 years ago. It doesn't do anything, but makes the >> macros harder to read, so get rid of it, and the fallback, no-op >> definition that they relied on. That requires removing a few uses >> outside list.h as well. >> >> checkpatch warns about some whitespace issues in list.h, but as I've >> copied whole kerneldoc+#define blocks directly from the linux kernel, >> I think it's better to just accept that so that we don't introduce >> needless diffs. The "macro argument reuse" arguments should also be >> ignored, as e.g. the "member" arguments are obviously always just bare >> identifiers, and the "pos" arguments must be assigned to multiple >> times. >> >> Rasmus Villemoes (4): >> linux/list.h: drop use of prefetch() >> treewide: drop no-op prefetch() calls >> mips: drop unused prefetch code and logic >> linux/list.h: drop fallback definition of prefetch() >> >> arch/mips/include/asm/processor.h | 16 ----- >> drivers/net/mvpp2.c | 1 - >> drivers/net/octeontx/nicvf_main.c | 2 - >> drivers/usb/gadget/at91_udc.c | 1 - >> drivers/usb/musb-new/musb_core.c | 2 - >> include/linux/list.h | 104 +++++++++++++++++------------- >> 6 files changed, 59 insertions(+), 67 deletions(-) > > Unfortunately this leads to build problems on lots of platforms: > https://source.denx.de/u-boot/u-boot/-/jobs/1141951
:( so we've been relying on that prefetch() laundering away the volatile. Which really begs the question: Why, exactly, is it that gd even has that volatile qualifier in the first place? I'm 98% certain that we could drop that and get better code generation and avoid a ton of places where we cast away that volatile which shouldn't really be there anyway. Rasmus
