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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-19 02:34:01 +08:00
linux-next/arch/xtensa
Peter Zijlstra 726328d92a locking/spinlock, arch: Update and fix spin_unlock_wait() implementations
This patch updates/fixes all spin_unlock_wait() implementations.

The update is in semantics; where it previously was only a control
dependency, we now upgrade to a full load-acquire to match the
store-release from the spin_unlock() we waited on. This ensures that
when spin_unlock_wait() returns, we're guaranteed to observe the full
critical section we waited on.

This fixes a number of spin_unlock_wait() users that (not
unreasonably) rely on this.

I also fixed a number of ticket lock versions to only wait on the
current lock holder, instead of for a full unlock, as this is
sufficient.

Furthermore; again for ticket locks; I added an smp_rmb() in between
the initial ticket load and the spin loop testing the current value
because I could not convince myself the address dependency is
sufficient, esp. if the loads are of different sizes.

I'm more than happy to remove this smp_rmb() again if people are
certain the address dependency does indeed work as expected.

Note: PPC32 will be fixed independently

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: chris@zankel.net
Cc: cmetcalf@mellanox.com
Cc: davem@davemloft.net
Cc: dhowells@redhat.com
Cc: james.hogan@imgtec.com
Cc: jejb@parisc-linux.org
Cc: linux@armlinux.org.uk
Cc: mpe@ellerman.id.au
Cc: ralf@linux-mips.org
Cc: realmz6@gmail.com
Cc: rkuo@codeaurora.org
Cc: rth@twiddle.net
Cc: schwidefsky@de.ibm.com
Cc: tony.luck@intel.com
Cc: vgupta@synopsys.com
Cc: ysato@users.sourceforge.jp
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-14 11:55:15 +02:00
..
boot xtensa: xtfpga: fix earlycon endianness 2016-03-11 08:53:32 +00:00
configs arch/defconfig: remove CONFIG_RESOURCE_COUNTERS 2016-05-23 17:04:14 -07:00
include locking/spinlock, arch: Update and fix spin_unlock_wait() implementations 2016-06-14 11:55:15 +02:00
kernel Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-05-25 17:05:40 -07:00
lib xtensa: fixes for configs without loop option 2015-11-02 18:02:47 +03:00
mm Xtensa improvements for 4.6: 2016-03-20 12:22:07 -07:00
oprofile xtensa: move oprofile stack tracing to stacktrace.c 2015-08-17 07:32:49 +03:00
platforms treewide: replace dev->trans_start update with helper 2016-05-04 14:16:49 -04:00
variants xtensa: add test_kc705_hifi variant 2016-03-17 21:17:04 +00:00
Kconfig exit_thread: remove empty bodies 2016-05-20 17:58:30 -07:00
Kconfig.debug xtensa: disable link optimization 2014-12-15 23:47:24 -08:00
Makefile xtensa: define CONFIG_CPU_{BIG,LITTLE}_ENDIAN 2016-03-11 08:53:31 +00:00