Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 1 Apr 2024 00:06:26 +0800 | From | Yujie Liu <> | Subject | Re: [paulmck-rcu:dev.2024.03.27b 61/69] lib/cmpxchg-emu.c:24:11: warning: no previous prototype for 'cmpxchg_emu_u8' |
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On Fri, Mar 29, 2024 at 04:08:10PM -0700, Paul E. McKenney wrote: > On Sat, Mar 30, 2024 at 05:26:12AM +0800, kernel test robot wrote: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2024.03.27b > > head: 786fab3085d764055a78edb54023420920344333 > > commit: b48ffed4c636b96d2be7a93806870772ce34961f [61/69] csky: Emulate one-byte and two-byte cmpxchg > > config: csky-allnoconfig (https://download.01.org/0day-ci/archive/20240330/202403300508.Xz7XNp71-lkp@intel.com/config) > > compiler: csky-linux-gcc (GCC) 13.2.0 > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240330/202403300508.Xz7XNp71-lkp@intel.com/reproduce) > > > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > > the same patch/commit), kindly add following tags > > | Reported-by: kernel test robot <lkp@intel.com> > > | Closes: https://lore.kernel.org/oe-kbuild-all/202403300508.Xz7XNp71-lkp@intel.com/ > > > > All warnings (new ones prefixed by >>): > > > > >> lib/cmpxchg-emu.c:24:11: warning: no previous prototype for 'cmpxchg_emu_u8' [-Wmissing-prototypes] > > 24 | uintptr_t cmpxchg_emu_u8(volatile u8 *p, uintptr_t old, uintptr_t new) > > | ^~~~~~~~~~~~~~ > > >> lib/cmpxchg-emu.c:51:11: warning: no previous prototype for 'cmpxchg_emu_u16' [-Wmissing-prototypes] > > 51 | uintptr_t cmpxchg_emu_u16(volatile u16 *p, uintptr_t old, uintptr_t new) > > | ^~~~~~~~~~~~~~~ > > Again, good catch, and thank you for the testing! Does the patch at the > end of this email fix things for you?
The warning is fixed by the patch at the end of the mail.
Tested-by: Yujie Liu <yujie.liu@intel.com>
> > Thanx, Paul > > > vim +/cmpxchg_emu_u8 +24 lib/cmpxchg-emu.c > > > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 22 > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 23 /* Emulate one-byte cmpxchg() in terms of 4-byte cmpxchg. */ > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 @24 uintptr_t cmpxchg_emu_u8(volatile u8 *p, uintptr_t old, uintptr_t new) > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 25 { > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 26 u32 *p32 = (u32 *)(((uintptr_t)p) & ~0x3); > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 27 int i = ((uintptr_t)p) & 0x3; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 28 union u8_32 old32; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 29 union u8_32 new32; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 30 u32 ret; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 31 > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 32 old32.w = READ_ONCE(*p32); > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 33 do { > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 34 if (old32.b[i] != old) > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 35 return old32.b[i]; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 36 new32.w = old32.w; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 37 new32.b[i] = new; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 38 instrument_atomic_read_write(p, 1); > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 39 ret = data_race(cmpxchg(p32, old32.w, new32.w)); > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 40 } while (ret != old32.w); > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 41 return old; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 42 } > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 43 EXPORT_SYMBOL_GPL(cmpxchg_emu_u8); > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 44 > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 45 union u16_32 { > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 46 u16 h[2]; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 47 u32 w; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 48 }; > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 49 > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 50 /* Emulate two-byte cmpxchg() in terms of 4-byte cmpxchg. */ > > 0bbce967f3ecfc Paul E. McKenney 2024-03-17 @51 uintptr_t cmpxchg_emu_u16(volatile u16 *p, uintptr_t old, uintptr_t new) > > > > :::::: The code at line 24 was first introduced by commit > > :::::: 0bbce967f3ecfc6da1e7e8756b0d398e791b8dee lib: Add one-byte and two-byte cmpxchg() emulation functions > > > > :::::: TO: Paul E. McKenney <paulmck@kernel.org> > > :::::: CC: Paul E. McKenney <paulmck@kernel.org> > > > > -- > > 0-DAY CI Kernel Test Service > > https://github.com/intel/lkp-tests/wiki > > commit a326496eb88936b291adea830c2e59e74ca1d373 > Author: Paul E. McKenney <paulmck@kernel.org> > Date: Fri Mar 29 16:06:45 2024 -0700 > > squash! lib: Add one-byte and two-byte cmpxchg() emulation functions > > [ paulmck: Apply kernel test robot feedback. ] > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > diff --git a/lib/cmpxchg-emu.c b/lib/cmpxchg-emu.c > index abdd451767220..a88c4f3c88430 100644 > --- a/lib/cmpxchg-emu.c > +++ b/lib/cmpxchg-emu.c > @@ -14,6 +14,7 @@ > #include <linux/panic.h> > #include <linux/bug.h> > #include <asm-generic/rwonce.h> > +#include <linux/cmpxchg-emu.h> > > union u8_32 { > u8 b[4]; >
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