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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-10-03 10:05:12 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-10-03 10:05:12 -0700 |
| commit | ff93026d51935b671b4ac131886f0914f8b6189a (patch) | |
| tree | 03bbcdb1eb122fbe830e0517e570112aaf2e5412 /include | |
| parent | c1de1591d927bc1e55095d642b3c3cc2e54fc1cd (diff) | |
| parent | 1fa4df3e688902d033dfda796eb83ae6ad8d0488 (diff) | |
Merge branch 'for-4.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull percpu fixes from Tejun Heo:
"Rather important fixes this time.
- The new percpu area allocator had a subtle bug in how it iterates
the memory regions and could skip viable areas, which led to
allocation failures for module static percpu variables. Dennis
fixed the bug and another non-critical one in stat calculation.
- Mark noticed that the generic implementations of percpu local
atomic reads aren't properly protected against irqs and there's a
(slim) chance for split reads on some 32bit systems. Generic
implementations are updated to disable irq when read size is larger
than ulong size. This may have made some 32bit archs which can do
atomic local 64bit accesses generate sub-optimal code. We need to
find them out and implement arch-specific overrides"
* 'for-4.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: fix iteration to prevent skipping over block
percpu: fix starting offset for chunk statistics traversal
percpu: make this_cpu_generic_read() atomic w.r.t. interrupts
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-generic/percpu.h | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h index 0504ef8f3aa3..976f8ac26665 100644 --- a/include/asm-generic/percpu.h +++ b/include/asm-generic/percpu.h @@ -115,15 +115,35 @@ do { \ (__ret); \ }) -#define this_cpu_generic_read(pcp) \ +#define __this_cpu_generic_read_nopreempt(pcp) \ ({ \ typeof(pcp) __ret; \ preempt_disable_notrace(); \ - __ret = raw_cpu_generic_read(pcp); \ + __ret = READ_ONCE(*raw_cpu_ptr(&(pcp))); \ preempt_enable_notrace(); \ __ret; \ }) +#define __this_cpu_generic_read_noirq(pcp) \ +({ \ + typeof(pcp) __ret; \ + unsigned long __flags; \ + raw_local_irq_save(__flags); \ + __ret = raw_cpu_generic_read(pcp); \ + raw_local_irq_restore(__flags); \ + __ret; \ +}) + +#define this_cpu_generic_read(pcp) \ +({ \ + typeof(pcp) __ret; \ + if (__native_word(pcp)) \ + __ret = __this_cpu_generic_read_nopreempt(pcp); \ + else \ + __ret = __this_cpu_generic_read_noirq(pcp); \ + __ret; \ +}) + #define this_cpu_generic_to_op(pcp, val, op) \ do { \ unsigned long __flags; \ |