Subject: Re: linux-next: manual merge of the tip tree with the asm-generic tree

From: Stephen Rothwell <[email-masked]>
Date: Wed, 1 Sep 2021 13:20:18 +1000

Hi all,

On Mon, 16 Aug 2021 11:47:40 +1000 Stephen Rothwell <[email-masked]> wrote:
>
> Today's linux-next merge of the tip tree got a conflict in:
> 
>   include/asm-generic/bitops/non-atomic.h
> 
> between commit:
> 
>   8f76f9c46952 ("bitops/non-atomic: make @nr unsigned to avoid any DIV")
> 
> from the asm-generic tree and commit:
> 
>   cf3ee3c8c29d ("locking/atomic: add generic arch_*() bitops")
> 
> from the tip tree.
> 
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
> 
> diff --cc include/asm-generic/bitops/non-atomic.h
> index c5a7d8eb9c2b,365377fb104b..000000000000
> --- a/include/asm-generic/bitops/non-atomic.h
> +++ b/include/asm-generic/bitops/non-atomic.h
> @@@ -13,15 -13,18 +13,18 @@@
>    * If it's called on the same region of memory simultaneously, the effect
>    * may be that only one operation succeeds.
>    */
> - static inline void __set_bit(unsigned int nr, volatile unsigned long *addr)
> + static __always_inline void
>  -arch___set_bit(int nr, volatile unsigned long *addr)
> ++arch___set_bit(unsigned int nr, volatile unsigned long *addr)
>   {
>   	unsigned long mask = BIT_MASK(nr);
>   	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
>   
>   	*p  |= mask;
>   }
> + #define __set_bit arch___set_bit
>   
> - static inline void __clear_bit(unsigned int nr, volatile unsigned long *addr)
> + static __always_inline void
>  -arch___clear_bit(int nr, volatile unsigned long *addr)
> ++arch___clear_bit(unsigned int nr, volatile unsigned long *addr)
>   {
>   	unsigned long mask = BIT_MASK(nr);
>   	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@@ -38,7 -42,8 +42,8 @@@
>    * If it's called on the same region of memory simultaneously, the effect
>    * may be that only one operation succeeds.
>    */
> - static inline void __change_bit(unsigned int nr, volatile unsigned long *addr)
> + static __always_inline
>  -void arch___change_bit(int nr, volatile unsigned long *addr)
> ++void arch___change_bit(unsigned int nr, volatile unsigned long *addr)
>   {
>   	unsigned long mask = BIT_MASK(nr);
>   	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@@ -55,7 -61,8 +61,8 @@@
>    * If two examples of this operation race, one can appear to succeed
>    * but actually fail.  You must protect multiple accesses with a lock.
>    */
> - static inline int __test_and_set_bit(unsigned int nr, volatile unsigned long *addr)
> + static __always_inline int
>  -arch___test_and_set_bit(int nr, volatile unsigned long *addr)
> ++arch___test_and_set_bit(unsigned int nr, volatile unsigned long *addr)
>   {
>   	unsigned long mask = BIT_MASK(nr);
>   	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@@ -74,7 -82,8 +82,8 @@@
>    * If two examples of this operation race, one can appear to succeed
>    * but actually fail.  You must protect multiple accesses with a lock.
>    */
> - static inline int __test_and_clear_bit(unsigned int nr, volatile unsigned long *addr)
> + static __always_inline int
>  -arch___test_and_clear_bit(int nr, volatile unsigned long *addr)
> ++arch___test_and_clear_bit(unsigned int nr, volatile unsigned long *addr)
>   {
>   	unsigned long mask = BIT_MASK(nr);
>   	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@@ -83,10 -92,11 +92,11 @@@
>   	*p = old & ~mask;
>   	return (old & mask) != 0;
>   }
> + #define __test_and_clear_bit arch___test_and_clear_bit
>   
>   /* WARNING: non atomic and it can be reordered! */
> - static inline int __test_and_change_bit(unsigned int nr,
> - 					    volatile unsigned long *addr)
> + static __always_inline int
>  -arch___test_and_change_bit(int nr, volatile unsigned long *addr)
> ++arch___test_and_change_bit(unsigned int nr, volatile unsigned long *addr)
>   {
>   	unsigned long mask = BIT_MASK(nr);
>   	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@@ -101,7 -112,8 +112,8 @@@
>    * @nr: bit number to test
>    * @addr: Address to start counting from
>    */
> - static inline int test_bit(unsigned int nr, const volatile unsigned long *addr)
> + static __always_inline int
>  -arch_test_bit(int nr, const volatile unsigned long *addr)
> ++arch_test_bit(unsigned int nr, const volatile unsigned long *addr)
>   {
>   	return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
>   }

This is now a conflict between the asm-generic tree and Linus' tree.

-- 
Cheers,
Stephen Rothwell