kernel.git/arch/parisc/include/asm/spinlock.h, branch linux-4.9.y

parisc: Remove unnecessary barriers from spinlock.h

2018-08-24T11:12:41Z

commit 3b885ac1dc35b87a39ee176a6c7e2af9c789d8b8 upstream. Now that mb() is an instruction barrier, it will slow performance if we issue unnecessary barriers. The spinlock defines have a number of unnecessary barriers. The __ldcw() define is both a hardware and compiler barrier. The mb() barriers in the routines using __ldcw() serve no purpose. The only barrier needed is the one in arch_spin_unlock(). We need to ensure all accesses are complete prior to releasing the lock. Signed-off-by: John David Anglin Cc: stable@vger.kernel.org # 4.0+ Signed-off-by: Helge Deller Signed-off-by: Greg Kroah-Hartman

locking/spinlock, arch: Update and fix spin_unlock_wait() implementations

2016-06-14T09:55:15Z

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) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner 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

parisc: locks: remove redundant arch_*_relax operations

2014-03-23T16:01:23Z

Now that the arch_{spin,read,write}_relax macros default to cpu_relax(), remove the redundant definitions for parisc. Cc: Helge Deller Signed-off-by: Will Deacon Signed-off-by: Helge Deller

parisc: add missing includes in asm/spinlock.h

2012-05-10T22:12:08Z

This leads to this errors: In file included from arch/parisc/include/asm/atomic.h:20:0, from include/linux/atomic.h:4, from arch/parisc/include/asm/bitops.h:56, from include/linux/bitops.h:22, from include/linux/kernel.h:19, from include/linux/sched.h:55, from arch/parisc/kernel/asm-offsets.c:31: arch/parisc/include/asm/spinlock.h: In function ‘arch_spin_is_locked’: arch/parisc/include/asm/spinlock.h:9:2: error: implicit declaration of function ‘__ldcw_align’ [-Werror=implicit-function-declaration] arch/parisc/include/asm/spinlock.h:9:29: warning: initialization makes pointer from integer without a cast [enabled by default] arch/parisc/include/asm/spinlock.h: In function ‘arch_spin_lock_flags’: arch/parisc/include/asm/spinlock.h:22:2: error: implicit declaration of function ‘mb’ [-Werror=implicit-function-declaration] arch/parisc/include/asm/spinlock.h:23:4: warning: assignment makes pointer from integer without a cast [enabled by default] arch/parisc/include/asm/spinlock.h:24:2: error: implicit declaration of function ‘__ldcw’ [-Werror=implicit-function-declaration] Signed-off-by: Rolf Eike Beer Signed-off-by: Linus Torvalds

Disintegrate asm/system.h for PA-RISC

2012-03-28T17:30:02Z

Disintegrate asm/system.h for PA-RISC. Signed-off-by: David Howells cc: linux-parisc@vger.kernel.org

locking: Convert raw_rwlock functions to arch_rwlock

2009-12-14T22:55:32Z

Name space cleanup for rwlock functions. No functional change. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Acked-by: David S. Miller Acked-by: Ingo Molnar Cc: linux-arch@vger.kernel.org

locking: Convert raw_rwlock to arch_rwlock

2009-12-14T22:55:32Z

Not strictly necessary for -rt as -rt does not have non sleeping rwlocks, but it's odd to not have a consistent naming convention. No functional change. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Acked-by: David S. Miller Acked-by: Ingo Molnar Cc: linux-arch@vger.kernel.org

locking: Convert __raw_spin* functions to arch_spin*

2009-12-14T22:55:32Z

Name space cleanup. No functional change. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Acked-by: David S. Miller Acked-by: Ingo Molnar Cc: linux-arch@vger.kernel.org

locking: Convert raw_spinlock to arch_spinlock

2009-12-14T22:55:32Z

The raw_spin* namespace was taken by lockdep for the architecture specific implementations. raw_spin_* would be the ideal name space for the spinlocks which are not converted to sleeping locks in preempt-rt. Linus suggested to convert the raw_ to arch_ locks and cleanup the name space instead of using an artifical name like core_spin, atomic_spin or whatever No functional change. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Acked-by: David S. Miller Acked-by: Ingo Molnar Cc: linux-arch@vger.kernel.org

Allow rwlocks to re-enable interrupts

2009-04-03T02:05:11Z

Pass the original flags to rwlock arch-code, so that it can re-enable interrupts if implemented for that architecture. Initially, make __raw_read_lock_flags and __raw_write_lock_flags stubs which just do the same thing as non-flags variants. Signed-off-by: Petr Tesarik Signed-off-by: Robin Holt Acked-by: Peter Zijlstra Cc: Acked-by: Ingo Molnar Cc: "Luck, Tony" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds