16 files changed, 15 insertions, 24 deletions

diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 9d5904cc7712..9b504af2e966 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -5,7 +5,6 @@ config ALPHA
         select HAVE_IDE
         select HAVE_OPROFILE
         select HAVE_SYSCALL_WRAPPERS
-        select HAVE_IRQ_WORK
         select HAVE_PCSPKR_PLATFORM
         select HAVE_PERF_EVENTS
         select HAVE_DMA_ATTRS
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 67874b82a4ed..9bbe760f2352 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -36,7 +36,6 @@ config ARM
         select HAVE_GENERIC_HARDIRQS
         select HAVE_HW_BREAKPOINT if (PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7))
         select HAVE_IDE if PCI || ISA || PCMCIA
-        select HAVE_IRQ_WORK
         select HAVE_KERNEL_GZIP
         select HAVE_KERNEL_LZMA
         select HAVE_KERNEL_LZO
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index f8f362aafee9..75e915b72471 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -21,7 +21,6 @@ config ARM64
         select HAVE_GENERIC_DMA_COHERENT
         select HAVE_GENERIC_HARDIRQS
         select HAVE_HW_BREAKPOINT if PERF_EVENTS
-        select HAVE_IRQ_WORK
         select HAVE_MEMBLOCK
         select HAVE_PERF_EVENTS
         select IRQ_DOMAIN
diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index b6f3ad5441c5..86f891f0ae48 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -24,7 +24,6 @@ config BLACKFIN
         select HAVE_FUNCTION_TRACER
         select HAVE_FUNCTION_TRACE_MCOUNT_TEST
         select HAVE_IDE
-        select HAVE_IRQ_WORK
         select HAVE_KERNEL_GZIP if RAMKERNEL
         select HAVE_KERNEL_BZIP2 if RAMKERNEL
         select HAVE_KERNEL_LZMA if RAMKERNEL
diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index 9d262645f667..17df48fc8f44 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -3,7 +3,6 @@ config FRV
         default y
         select HAVE_IDE
         select HAVE_ARCH_TRACEHOOK
-        select HAVE_IRQ_WORK
         select HAVE_PERF_EVENTS
         select HAVE_UID16
         select HAVE_GENERIC_HARDIRQS
diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig
index 0744f7d7b1fd..40a318594ae7 100644
--- a/arch/hexagon/Kconfig
+++ b/arch/hexagon/Kconfig
@@ -14,7 +14,6 @@ config HEXAGON
         # select HAVE_CLK
         # select IRQ_PER_CPU
         # select GENERIC_PENDING_IRQ if SMP
-        select HAVE_IRQ_WORK
         select GENERIC_ATOMIC64
         select HAVE_PERF_EVENTS
         select HAVE_GENERIC_HARDIRQS
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 2ac626ab9d43..121ed51ac227 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -4,7 +4,6 @@ config MIPS
         select HAVE_GENERIC_DMA_COHERENT
         select HAVE_IDE
         select HAVE_OPROFILE
-        select HAVE_IRQ_WORK
         select HAVE_PERF_EVENTS
         select PERF_USE_VMALLOC
         select HAVE_ARCH_KGDB
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index b77feffbadea..9dd5c1888878 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -9,7 +9,6 @@ config PARISC
         select RTC_DRV_GENERIC
         select INIT_ALL_POSSIBLE
         select BUG
-        select HAVE_IRQ_WORK
         select HAVE_PERF_EVENTS
         select GENERIC_ATOMIC64 if !64BIT
         select HAVE_GENERIC_HARDIRQS
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 17903f1f356b..d45edca88b57 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -118,7 +118,6 @@ config PPC
         select HAVE_SYSCALL_WRAPPERS if PPC64
         select GENERIC_ATOMIC64 if PPC32
         select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
-        select HAVE_IRQ_WORK
         select HAVE_PERF_EVENTS
         select HAVE_REGS_AND_STACK_ACCESS_API
         select HAVE_HW_BREAKPOINT if PERF_EVENTS && PPC_BOOK3S_64
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index b5ea38c25647..c15ba7d1be64 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -78,7 +78,6 @@ config S390
         select HAVE_KVM if 64BIT
         select HAVE_ARCH_TRACEHOOK
         select INIT_ALL_POSSIBLE
-        select HAVE_IRQ_WORK
         select HAVE_PERF_EVENTS
         select ARCH_HAVE_NMI_SAFE_CMPXCHG
         select HAVE_DEBUG_KMEMLEAK
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index babc2b826c5c..996e008aaa3e 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -11,7 +11,6 @@ config SUPERH
         select HAVE_ARCH_TRACEHOOK
         select HAVE_DMA_API_DEBUG
         select HAVE_DMA_ATTRS
-        select HAVE_IRQ_WORK
         select HAVE_PERF_EVENTS
         select HAVE_DEBUG_BUGVERBOSE
         select ARCH_HAVE_CUSTOM_GPIO_H
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 9f2edb5c5551..ed937ae72df3 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -23,7 +23,6 @@ config SPARC
         select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
         select RTC_CLASS
         select RTC_DRV_M48T59
-        select HAVE_IRQ_WORK
         select HAVE_DMA_ATTRS
         select HAVE_DMA_API_DEBUG
         select HAVE_ARCH_JUMP_LABEL
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 79795af59810..5d3d61f40b31 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -28,7 +28,6 @@ config X86
         select HAVE_OPROFILE
         select HAVE_PCSPKR_PLATFORM
         select HAVE_PERF_EVENTS
-        select HAVE_IRQ_WORK
         select HAVE_IOREMAP_PROT
         select HAVE_KPROBES
         select HAVE_MEMBLOCK
diff --git a/drivers/staging/iio/trigger/Kconfig b/drivers/staging/iio/trigger/Kconfig
index 7d3207559265..d44d3ad26fa5 100644
--- a/drivers/staging/iio/trigger/Kconfig
+++ b/drivers/staging/iio/trigger/Kconfig
@@ -21,7 +21,6 @@ config IIO_GPIO_TRIGGER
 config IIO_SYSFS_TRIGGER
         tristate "SYSFS trigger"
         depends on SYSFS
-        depends on HAVE_IRQ_WORK
         select IRQ_WORK
         help
           Provides support for using SYSFS entry as IIO triggers.
diff --git a/init/Kconfig b/init/Kconfig
index be8b7f55312d..e3227d7ba35d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -20,12 +20,8 @@ config CONSTRUCTORS
         bool
         depends on !UML
 
-config HAVE_IRQ_WORK
-        bool
-
 config IRQ_WORK
         bool
-        depends on HAVE_IRQ_WORK
 
 config BUILDTIME_EXTABLE_SORT
         bool
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 1588e3b2871b..64eddd59ed83 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -34,15 +34,21 @@ static DEFINE_PER_CPU(struct llist_head, irq_work_list);
  */
 static bool irq_work_claim(struct irq_work *work)
 {
-        unsigned long flags, nflags;
+        unsigned long flags, oflags, nflags;
 
+        /*
+         * Start with our best wish as a premise but only trust any
+         * flag value after cmpxchg() result.
+         */
+        flags = work->flags & ~IRQ_WORK_PENDING;
         for (;;) {
-                flags = work->flags;
-                if (flags & IRQ_WORK_PENDING)
-                        return false;
                 nflags = flags | IRQ_WORK_FLAGS;
-                if (cmpxchg(&work->flags, flags, nflags) == flags)
+                oflags = cmpxchg(&work->flags, flags, nflags);
+                if (oflags == flags)
                         break;
+                if (oflags & IRQ_WORK_PENDING)
+                        return false;
+                flags = oflags;
                 cpu_relax();
         }
 
@@ -119,8 +125,11 @@ void irq_work_run(void)
                 /*
                  * Clear the PENDING bit, after this point the @work
                  * can be re-used.
+                 * Make it immediately visible so that other CPUs trying
+                 * to claim that work don't rely on us to handle their data
+                 * while we are in the middle of the func.
                  */
-                work->flags = IRQ_WORK_BUSY;
+                xchg(&work->flags, IRQ_WORK_BUSY);
                 work->func(work);
                 /*
                  * Clear the BUSY bit and return to the free state if