From 2cb7c9cb426660b5ed58b643d9e7dd5d50ba901f Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 11 May 2015 17:52:09 +0200 Subject: [PATCH] sched/preempt, mm/kmap: Explicitly disable/enable preemption in kmap_atomic_* The existing code relies on pagefault_disable() implicitly disabling preemption, so that no schedule will happen between kmap_atomic() and kunmap_atomic(). Let's make this explicit, to prepare for pagefault_disable() not touching preemption anymore. Reviewed-and-tested-by: Thomas Gleixner Signed-off-by: David Hildenbrand Signed-off-by: Peter Zijlstra (Intel) Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-5-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- arch/arm/mm/highmem.c | 3 +++ arch/frv/mm/highmem.c | 2 ++ arch/metag/mm/highmem.c | 4 +++- arch/microblaze/mm/highmem.c | 4 +++- arch/mips/mm/highmem.c | 5 ++++- arch/mn10300/include/asm/highmem.h | 3 +++ arch/parisc/include/asm/cacheflush.h | 2 ++ arch/powerpc/mm/highmem.c | 4 +++- arch/sparc/mm/highmem.c | 4 +++- arch/tile/mm/highmem.c | 3 ++- arch/x86/mm/highmem_32.c | 3 ++- arch/x86/mm/iomap_32.c | 2 ++ arch/xtensa/mm/highmem.c | 2 ++ include/linux/highmem.h | 2 ++ include/linux/io-mapping.h | 2 ++ 15 files changed, 38 insertions(+), 7 deletions(-) diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c index b98895d9fe57..ee8dfa793989 100644 --- a/arch/arm/mm/highmem.c +++ b/arch/arm/mm/highmem.c @@ -59,6 +59,7 @@ void *kmap_atomic(struct page *page) void *kmap; int type; + preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) return page_address(page); @@ -121,6 +122,7 @@ void __kunmap_atomic(void *kvaddr) kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)])); } pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); @@ -130,6 +132,7 @@ void *kmap_atomic_pfn(unsigned long pfn) int idx, type; struct page *page = pfn_to_page(pfn); + preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) return page_address(page); diff --git a/arch/frv/mm/highmem.c b/arch/frv/mm/highmem.c index bed9a9bd3c10..785344bbdc07 100644 --- a/arch/frv/mm/highmem.c +++ b/arch/frv/mm/highmem.c @@ -42,6 +42,7 @@ void *kmap_atomic(struct page *page) unsigned long paddr; int type; + preempt_disable(); pagefault_disable(); type = kmap_atomic_idx_push(); paddr = page_to_phys(page); @@ -85,5 +86,6 @@ void __kunmap_atomic(void *kvaddr) } kmap_atomic_idx_pop(); pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); diff --git a/arch/metag/mm/highmem.c b/arch/metag/mm/highmem.c index d71f621a2c0b..807f1b1c4e65 100644 --- a/arch/metag/mm/highmem.c +++ b/arch/metag/mm/highmem.c @@ -43,7 +43,7 @@ void *kmap_atomic(struct page *page) unsigned long vaddr; int type; - /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ + preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) return page_address(page); @@ -82,6 +82,7 @@ void __kunmap_atomic(void *kvaddr) } pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); @@ -95,6 +96,7 @@ void *kmap_atomic_pfn(unsigned long pfn) unsigned long vaddr; int type; + preempt_disable(); pagefault_disable(); type = kmap_atomic_idx_push(); diff --git a/arch/microblaze/mm/highmem.c b/arch/microblaze/mm/highmem.c index 5a92576fad92..2fcc5a52d84d 100644 --- a/arch/microblaze/mm/highmem.c +++ b/arch/microblaze/mm/highmem.c @@ -37,7 +37,7 @@ void *kmap_atomic_prot(struct page *page, pgprot_t prot) unsigned long vaddr; int idx, type; - /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ + preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) return page_address(page); @@ -63,6 +63,7 @@ void __kunmap_atomic(void *kvaddr) if (vaddr < __fix_to_virt(FIX_KMAP_END)) { pagefault_enable(); + preempt_enable(); return; } @@ -84,5 +85,6 @@ void __kunmap_atomic(void *kvaddr) #endif kmap_atomic_idx_pop(); pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); diff --git a/arch/mips/mm/highmem.c b/arch/mips/mm/highmem.c index da815d295239..11661cbc11a8 100644 --- a/arch/mips/mm/highmem.c +++ b/arch/mips/mm/highmem.c @@ -47,7 +47,7 @@ void *kmap_atomic(struct page *page) unsigned long vaddr; int idx, type; - /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ + preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) return page_address(page); @@ -72,6 +72,7 @@ void __kunmap_atomic(void *kvaddr) if (vaddr < FIXADDR_START) { // FIXME pagefault_enable(); + preempt_enable(); return; } @@ -92,6 +93,7 @@ void __kunmap_atomic(void *kvaddr) #endif kmap_atomic_idx_pop(); pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); @@ -104,6 +106,7 @@ void *kmap_atomic_pfn(unsigned long pfn) unsigned long vaddr; int idx, type; + preempt_disable(); pagefault_disable(); type = kmap_atomic_idx_push(); diff --git a/arch/mn10300/include/asm/highmem.h b/arch/mn10300/include/asm/highmem.h index 2fbbe4d920aa..1ddea5afba09 100644 --- a/arch/mn10300/include/asm/highmem.h +++ b/arch/mn10300/include/asm/highmem.h @@ -75,6 +75,7 @@ static inline void *kmap_atomic(struct page *page) unsigned long vaddr; int idx, type; + preempt_disable(); pagefault_disable(); if (page < highmem_start_page) return page_address(page); @@ -98,6 +99,7 @@ static inline void __kunmap_atomic(unsigned long vaddr) if (vaddr < FIXADDR_START) { /* FIXME */ pagefault_enable(); + preempt_enable(); return; } @@ -122,6 +124,7 @@ static inline void __kunmap_atomic(unsigned long vaddr) kmap_atomic_idx_pop(); pagefault_enable(); + preempt_enable(); } #endif /* __KERNEL__ */ diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h index de65f66ea64e..ec2df4bab302 100644 --- a/arch/parisc/include/asm/cacheflush.h +++ b/arch/parisc/include/asm/cacheflush.h @@ -142,6 +142,7 @@ static inline void kunmap(struct page *page) static inline void *kmap_atomic(struct page *page) { + preempt_disable(); pagefault_disable(); return page_address(page); } @@ -150,6 +151,7 @@ static inline void __kunmap_atomic(void *addr) { flush_kernel_dcache_page_addr(addr); pagefault_enable(); + preempt_enable(); } #define kmap_atomic_prot(page, prot) kmap_atomic(page) diff --git a/arch/powerpc/mm/highmem.c b/arch/powerpc/mm/highmem.c index e7450bdbe83a..e292c8a60952 100644 --- a/arch/powerpc/mm/highmem.c +++ b/arch/powerpc/mm/highmem.c @@ -34,7 +34,7 @@ void *kmap_atomic_prot(struct page *page, pgprot_t prot) unsigned long vaddr; int idx, type; - /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ + preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) return page_address(page); @@ -59,6 +59,7 @@ void __kunmap_atomic(void *kvaddr) if (vaddr < __fix_to_virt(FIX_KMAP_END)) { pagefault_enable(); + preempt_enable(); return; } @@ -82,5 +83,6 @@ void __kunmap_atomic(void *kvaddr) kmap_atomic_idx_pop(); pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); diff --git a/arch/sparc/mm/highmem.c b/arch/sparc/mm/highmem.c index 449f864f0cef..a454ec5ff07a 100644 --- a/arch/sparc/mm/highmem.c +++ b/arch/sparc/mm/highmem.c @@ -53,7 +53,7 @@ void *kmap_atomic(struct page *page) unsigned long vaddr; long idx, type; - /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ + preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) return page_address(page); @@ -91,6 +91,7 @@ void __kunmap_atomic(void *kvaddr) if (vaddr < FIXADDR_START) { // FIXME pagefault_enable(); + preempt_enable(); return; } @@ -126,5 +127,6 @@ void __kunmap_atomic(void *kvaddr) kmap_atomic_idx_pop(); pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); diff --git a/arch/tile/mm/highmem.c b/arch/tile/mm/highmem.c index 6aa2f2625447..fcd545014e79 100644 --- a/arch/tile/mm/highmem.c +++ b/arch/tile/mm/highmem.c @@ -201,7 +201,7 @@ void *kmap_atomic_prot(struct page *page, pgprot_t prot) int idx, type; pte_t *pte; - /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ + preempt_disable(); pagefault_disable(); /* Avoid icache flushes by disallowing atomic executable mappings. */ @@ -259,6 +259,7 @@ void __kunmap_atomic(void *kvaddr) } pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c index 4500142bc4aa..eecb207a2037 100644 --- a/arch/x86/mm/highmem_32.c +++ b/arch/x86/mm/highmem_32.c @@ -35,7 +35,7 @@ void *kmap_atomic_prot(struct page *page, pgprot_t prot) unsigned long vaddr; int idx, type; - /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ + preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) @@ -100,6 +100,7 @@ void __kunmap_atomic(void *kvaddr) #endif pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c index 9ca35fc60cfe..2b7ece0e103a 100644 --- a/arch/x86/mm/iomap_32.c +++ b/arch/x86/mm/iomap_32.c @@ -59,6 +59,7 @@ void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot) unsigned long vaddr; int idx, type; + preempt_disable(); pagefault_disable(); type = kmap_atomic_idx_push(); @@ -117,5 +118,6 @@ iounmap_atomic(void __iomem *kvaddr) } pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL_GPL(iounmap_atomic); diff --git a/arch/xtensa/mm/highmem.c b/arch/xtensa/mm/highmem.c index 8cfb71ec0937..184ceadccc1a 100644 --- a/arch/xtensa/mm/highmem.c +++ b/arch/xtensa/mm/highmem.c @@ -42,6 +42,7 @@ void *kmap_atomic(struct page *page) enum fixed_addresses idx; unsigned long vaddr; + preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) return page_address(page); @@ -79,6 +80,7 @@ void __kunmap_atomic(void *kvaddr) } pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 9286a46b7d69..6aefcd0031a6 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -65,6 +65,7 @@ static inline void kunmap(struct page *page) static inline void *kmap_atomic(struct page *page) { + preempt_disable(); pagefault_disable(); return page_address(page); } @@ -73,6 +74,7 @@ static inline void *kmap_atomic(struct page *page) static inline void __kunmap_atomic(void *addr) { pagefault_enable(); + preempt_enable(); } #define kmap_atomic_pfn(pfn) kmap_atomic(pfn_to_page(pfn)) diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h index 657fab4efab3..c27dde7215b5 100644 --- a/include/linux/io-mapping.h +++ b/include/linux/io-mapping.h @@ -141,6 +141,7 @@ static inline void __iomem * io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) { + preempt_disable(); pagefault_disable(); return ((char __force __iomem *) mapping) + offset; } @@ -149,6 +150,7 @@ static inline void io_mapping_unmap_atomic(void __iomem *vaddr) { pagefault_enable(); + preempt_enable(); } /* Non-atomic map/unmap */