Hi Rusty,
On Thu, 28 May 2015 17:25:07 +1000 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> Today's linux-next merge of the rcu tree got a conflict in
> include/linux/rcupdate.h between commits 0a04b0166929 ("rcu: Move
> lockless_dereference() out of rcupdate.h") from the modules tree and
> c1ad348b452a ("tick: Nohz: Rework next timer evaluation") from the tip
> tree and commits 7d0ae8086b82 ("rcu: Convert ACCESS_ONCE() to
> READ_ONCE() and WRITE_ONCE()") and 3382adbc1bb8 ("rcu: Eliminate a few
> CONFIG_RCU_NOCB_CPU_ALL #ifdefs") from the rcu tree.
>
> I fixed it up (see below) and can carry the fix as necessary (no action
> is required).
>
> I also had to add this merge fix patch:
>
> From: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Date: Thu, 28 May 2015 17:20:58 +1000
> Subject: [PATCH] rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and
> WRITE_ONCE()
>
> Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> ---
> include/linux/compiler.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index ba91e5c88a32..f7e7235f3a91 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -483,7 +483,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
> */
> #define lockless_dereference(p) \
> ({ \
> - typeof(p) _________p1 = ACCESS_ONCE(p); \
> + typeof(p) _________p1 = READ_ONCE(p); \
> smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
> (_________p1); \
> })
> --
> 2.1.4
>
> --
> Cheers,
> Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
>
> diff --cc include/linux/rcupdate.h
> index ed5f66464ab3,3a4d1bf430b1..000000000000
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@@ -1140,13 -1063,13 +1050,13 @@@ static inline notrace void rcu_read_unl
> #define kfree_rcu(ptr, rcu_head) \
> __kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head))
>
> - #if defined(CONFIG_TINY_RCU) || defined(CONFIG_RCU_NOCB_CPU_ALL)
> + #ifdef CONFIG_TINY_RCU
> -static inline int rcu_needs_cpu(unsigned long *delta_jiffies)
> +static inline int rcu_needs_cpu(u64 basemono, u64 *nextevt)
> {
> - *delta_jiffies = ULONG_MAX;
> + *nextevt = KTIME_MAX;
> return 0;
> }
> - #endif /* #if defined(CONFIG_TINY_RCU) || defined(CONFIG_RCU_NOCB_CPU_ALL) */
> + #endif /* #ifdef CONFIG_TINY_RCU */
>
> #if defined(CONFIG_RCU_NOCB_CPU_ALL)
> static inline bool rcu_is_nocb_cpu(int cpu) { return true; }
The above resolutions are now needed when the modules tree is merged
into Linus' tree (as the tip and rcu parts have already been merged).
--
Cheers,
Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
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