Message ID | c88fafb4-47d9-49b6-aeb6-5a83c9778791@paulmck-laptop |
---|---|
State | New |
Headers | show |
Series | ARC: Use __force to suppress per-CPU cmpxchg complaints | expand |
On 10/9/24 10:55, Paul E. McKenney wrote: > Currently, the cast of the first argument to cmpxchg_emu_u8() drops the > __percpu address-space designator, which results in sparse complaints > when applying cmpxchg() to per-CPU variables in ARC. Therefore, use > __force to suppress these complaints, given that this does not pertain > to cmpxchg() semantics, which are plently well-defined on variables in > general, whether per-CPU or otherwise. > > Reported-by: kernel test robot <lkp@intel.com> > Closes: https://lore.kernel.org/oe-kbuild-all/202409251336.ToC0TvWB-lkp@intel.com/ > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > Cc: Vineet Gupta <vgupta@kernel.org> > Cc: <linux-snps-arc@lists.infradead.org> > > diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h > index 58045c8983404..76f43db0890fc 100644 > --- a/arch/arc/include/asm/cmpxchg.h > +++ b/arch/arc/include/asm/cmpxchg.h > @@ -48,7 +48,7 @@ > \ > switch(sizeof((_p_))) { \ > case 1: \ > - _prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)_p_, (uintptr_t)_o_, (uintptr_t)_n_); \ > + _prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *__force)_p_, (uintptr_t)_o_, (uintptr_t)_n_); \ > break; \ > case 4: \ > _prev_ = __cmpxchg(_p_, _o_, _n_); \ Added to for-curr. Thx, -Vineet
On Tue, Oct 15, 2024 at 10:33:14PM -0700, Vineet Gupta wrote: > On 10/9/24 10:55, Paul E. McKenney wrote: > > Currently, the cast of the first argument to cmpxchg_emu_u8() drops the > > __percpu address-space designator, which results in sparse complaints > > when applying cmpxchg() to per-CPU variables in ARC. Therefore, use > > __force to suppress these complaints, given that this does not pertain > > to cmpxchg() semantics, which are plently well-defined on variables in > > general, whether per-CPU or otherwise. > > > > Reported-by: kernel test robot <lkp@intel.com> > > Closes: https://lore.kernel.org/oe-kbuild-all/202409251336.ToC0TvWB-lkp@intel.com/ > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > Cc: Vineet Gupta <vgupta@kernel.org> > > Cc: <linux-snps-arc@lists.infradead.org> > > > > diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h > > index 58045c8983404..76f43db0890fc 100644 > > --- a/arch/arc/include/asm/cmpxchg.h > > +++ b/arch/arc/include/asm/cmpxchg.h > > @@ -48,7 +48,7 @@ > > \ > > switch(sizeof((_p_))) { \ > > case 1: \ > > - _prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)_p_, (uintptr_t)_o_, (uintptr_t)_n_); \ > > + _prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *__force)_p_, (uintptr_t)_o_, (uintptr_t)_n_); \ > > break; \ > > case 4: \ > > _prev_ = __cmpxchg(_p_, _o_, _n_); \ > > > Added to for-curr. Thank you! As soon as it shows up in -next, I will drop it from my tree. Thanx, Paul
diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h index 58045c8983404..76f43db0890fc 100644 --- a/arch/arc/include/asm/cmpxchg.h +++ b/arch/arc/include/asm/cmpxchg.h @@ -48,7 +48,7 @@ \ switch(sizeof((_p_))) { \ case 1: \ - _prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)_p_, (uintptr_t)_o_, (uintptr_t)_n_); \ + _prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *__force)_p_, (uintptr_t)_o_, (uintptr_t)_n_); \ break; \ case 4: \ _prev_ = __cmpxchg(_p_, _o_, _n_); \
Currently, the cast of the first argument to cmpxchg_emu_u8() drops the __percpu address-space designator, which results in sparse complaints when applying cmpxchg() to per-CPU variables in ARC. Therefore, use __force to suppress these complaints, given that this does not pertain to cmpxchg() semantics, which are plently well-defined on variables in general, whether per-CPU or otherwise. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202409251336.ToC0TvWB-lkp@intel.com/ Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Vineet Gupta <vgupta@kernel.org> Cc: <linux-snps-arc@lists.infradead.org>