kernel/linux.git/include/linux/atomic.h, branch v3.16.76

arch: Prepare for smp_mb__{before,after}_atomic()

2014-04-18T09:40:30+00:00

Since the smp_mb__{before,after}*() ops are fundamentally dependent on how an arch can implement atomics it doesn't make sense to have 3 variants of them. They must all be the same. Furthermore, the 3 variants suggest they're only valid for those 3 atomic ops, while we have many more where they could be applied. So move away from smp_mb__{before,after}_{atomic,clear}_{dec,inc,bit}() and reduce the interface to just the two: smp_mb__{before,after}_atomic(). This patch prepares the way by introducing default implementations in asm-generic/barrier.h that default to a full barrier and providing __deprecated inlines for the previous 6 barriers if they're not provided by the arch. This should allow for a mostly painless transition (lots of deprecated warns in the interim). Signed-off-by: Peter Zijlstra Acked-by: Paul E. McKenney Link: http://lkml.kernel.org/n/tip-wr59327qdyi9mbzn6x937s4e@git.kernel.org Cc: Arnd Bergmann Cc: "Chen, Gong" Cc: John Sullivan Cc: Linus Torvalds Cc: Mauro Carvalho Chehab Cc: Srinivas Pandruvada Cc: "Theodore Ts'o" Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

atomic: implement generic atomic_dec_if_positive()

2012-10-09T07:22:46+00:00

The x86 implementation of atomic_dec_if_positive is quite generic, so make it available to all architectures. This is needed for "swap: add a simple detector for inappropriate swapin readahead". [akpm@linux-foundation.org: do the "#define foo foo" trick in the conventional manner] Signed-off-by: Shaohua Li Cc: Stephen Rothwell Cc: "David S. Miller" Cc: Rik van Riel Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Benjamin Herrenschmidt Cc: Michal Simek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

atomic: Allow atomic_inc_not_zero to be overridden

2012-03-07T06:06:08+00:00

We want to implement a ppc64 specific version of atomic_inc_not_zero so wrap it in an ifdef to allow it to be overridden. Signed-off-by: Anton Blanchard Acked-by: Mike Frysinger Signed-off-by: Benjamin Herrenschmidt

atomic: Update comments in atomic.h

2011-07-26T23:49:47+00:00

This clarifies the differences between and Signed-off-by: Arun Sharma Suggested-by: Mike Frysinger Cc: Eric Dumazet Cc: Ingo Molnar Cc: David Miller Acked-by: Mike Frysinger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

atomic: cleanup asm-generic atomic*.h inclusion

2011-07-26T23:49:47+00:00

After changing all consumers of atomics to include , we ran into some compile time errors due to this dependency chain: linux/atomic.h -> asm/atomic.h -> asm-generic/atomic-long.h where atomic-long.h could use funcs defined later in linux/atomic.h without a prototype. This patches moves the code that includes asm-generic/atomic*.h to linux/atomic.h. Archs that need need to select CONFIG_GENERIC_ATOMIC64 from now on (some of them used to include it unconditionally). Compile tested on i386 and x86_64 with allnoconfig. Signed-off-by: Arun Sharma Cc: Eric Dumazet Cc: Ingo Molnar Cc: David Miller Acked-by: Mike Frysinger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

atomic: move atomic_add_unless to generic code

2011-07-26T23:49:47+00:00

This is in preparation for more generic atomic primitives based on __atomic_add_unless. Signed-off-by: Arun Sharma Signed-off-by: Hans-Christian Egtvedt Reviewed-by: Eric Dumazet Cc: Ingo Molnar Cc: David Miller Acked-by: Mike Frysinger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

atomic: use

2011-07-26T23:49:47+00:00

This allows us to move duplicated code in (atomic_inc_not_zero() for now) to Signed-off-by: Arun Sharma Reviewed-by: Eric Dumazet Cc: Ingo Molnar Cc: David Miller Cc: Eric Dumazet Acked-by: Mike Frysinger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lockless get_write_access/deny_write_access

2011-07-20T05:43:14+00:00

new helpers: atomic_inc_unless_negative()/atomic_dec_unless_positive() Signed-off-by: Al Viro

atomic: Add atomic_or()

2011-05-28T15:41:46+00:00

An atomic_or() function is needed by TREE_RCU to avoid deadlock, so add a generic version. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Signed-off-by: Ingo Molnar

atomic: add atomic_inc_not_zero_hint()

2010-11-12T15:55:30+00:00

Followup of perf tools session in Netfilter WorkShop 2010 In the network stack we make high usage of atomic_inc_not_zero() in contexts we know the probable value of atomic before increment (2 for udp sockets for example) Using a special version of atomic_inc_not_zero() giving this hint can help processor to use less bus transactions. On x86 (MESI protocol) for example, this avoids entering Shared state, because "lock cmpxchg" issues an RFO (Read For Ownership) akpm: Adds a new include/linux/atomic.h. This means that new code should henceforth include linux/atomic.h and not asm/atomic.h. The presence of include/linux/atomic.h will in fact cause checkpatch.pl to warn about use of asm/atomic.h. The new include/linux/atomic.h becomes the place where arch-neutral atomic_t code should be placed. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Eric Dumazet Cc: Christoph Lameter Cc: Ingo Molnar Cc: Andi Kleen Cc: Arnaldo Carvalho de Melo Cc: David Miller Cc: "Paul E. McKenney" Cc: Nick Piggin Reviewed-by: "Paul E. McKenney" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds