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* locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns ↵Mark Rutland2017-10-251-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* misc: mic: Fix randconfig build error by including errno.hSudeep Dutt2015-06-121-0/+1
| | | | | | | | | This issue was reported @ https://lkml.org/lkml/2015/6/9/731 Reported-by: Jim Davis <jim.epost@gmail.com> Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* misc: mic: SCIF ring buffer infrastructureSudeep Dutt2015-05-241-0/+248
SCIF ring buffer is a single producer, single consumer byte stream ring buffer optimized for avoiding reads across the PCIe bus while adding the required barriers and hardware workarounds for the MIC Coprocessor. The ring buffer is used to implement a receive queue for SCIF driver messaging between two nodes and for byte stream messaging between SCIF endpoints. The existing in-kernel ring buffer was not reused since it has not been designed for our use across the PCIe bus where each node runs an independent OS. Each SCIF node has a receive queue for every other SCIF node, and each connected endpoint has a receive queue for messages from its peer. This pair of receive queues is referred to as a SCIF queue pair. Reviewed-by: Nikhil Rao <nikhil.rao@intel.com> Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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