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 <tglx@linutronix.de>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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 <mingo@kernel.org>
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
index b98895d..ee8dfa7 100644
--- a/arch/arm/mm/highmem.c
+++ b/arch/arm/mm/highmem.c
@@ -59,6 +59,7 @@
void *kmap;
int type;
+ preempt_disable();
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
@@ -121,6 +122,7 @@
kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
}
pagefault_enable();
+ preempt_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);
@@ -130,6 +132,7 @@
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 bed9a9b..785344b 100644
--- a/arch/frv/mm/highmem.c
+++ b/arch/frv/mm/highmem.c
@@ -42,6 +42,7 @@
unsigned long paddr;
int type;
+ preempt_disable();
pagefault_disable();
type = kmap_atomic_idx_push();
paddr = page_to_phys(page);
@@ -85,5 +86,6 @@
}
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 d71f621..807f1b1 100644
--- a/arch/metag/mm/highmem.c
+++ b/arch/metag/mm/highmem.c
@@ -43,7 +43,7 @@
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 @@
}
pagefault_enable();
+ preempt_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);
@@ -95,6 +96,7 @@
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 5a92576..2fcc5a5 100644
--- a/arch/microblaze/mm/highmem.c
+++ b/arch/microblaze/mm/highmem.c
@@ -37,7 +37,7 @@
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 @@
if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
pagefault_enable();
+ preempt_enable();
return;
}
@@ -84,5 +85,6 @@
#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 da815d2..11661cb 100644
--- a/arch/mips/mm/highmem.c
+++ b/arch/mips/mm/highmem.c
@@ -47,7 +47,7 @@
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 @@
if (vaddr < FIXADDR_START) { // FIXME
pagefault_enable();
+ preempt_enable();
return;
}
@@ -92,6 +93,7 @@
#endif
kmap_atomic_idx_pop();
pagefault_enable();
+ preempt_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);
@@ -104,6 +106,7 @@
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 2fbbe4d..1ddea5a 100644
--- a/arch/mn10300/include/asm/highmem.h
+++ b/arch/mn10300/include/asm/highmem.h
@@ -75,6 +75,7 @@
unsigned long vaddr;
int idx, type;
+ preempt_disable();
pagefault_disable();
if (page < highmem_start_page)
return page_address(page);
@@ -98,6 +99,7 @@
if (vaddr < FIXADDR_START) { /* FIXME */
pagefault_enable();
+ preempt_enable();
return;
}
@@ -122,6 +124,7 @@
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 de65f66..ec2df4b 100644
--- a/arch/parisc/include/asm/cacheflush.h
+++ b/arch/parisc/include/asm/cacheflush.h
@@ -142,6 +142,7 @@
static inline void *kmap_atomic(struct page *page)
{
+ preempt_disable();
pagefault_disable();
return page_address(page);
}
@@ -150,6 +151,7 @@
{
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 e7450bd..e292c8a 100644
--- a/arch/powerpc/mm/highmem.c
+++ b/arch/powerpc/mm/highmem.c
@@ -34,7 +34,7 @@
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 @@
if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
pagefault_enable();
+ preempt_enable();
return;
}
@@ -82,5 +83,6 @@
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 449f864..a454ec5 100644
--- a/arch/sparc/mm/highmem.c
+++ b/arch/sparc/mm/highmem.c
@@ -53,7 +53,7 @@
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 @@
if (vaddr < FIXADDR_START) { // FIXME
pagefault_enable();
+ preempt_enable();
return;
}
@@ -126,5 +127,6 @@
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 6aa2f26..fcd5450 100644
--- a/arch/tile/mm/highmem.c
+++ b/arch/tile/mm/highmem.c
@@ -201,7 +201,7 @@
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 @@
}
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 4500142..eecb207a 100644
--- a/arch/x86/mm/highmem_32.c
+++ b/arch/x86/mm/highmem_32.c
@@ -35,7 +35,7 @@
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 @@
#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 9ca35fc..2b7ece0 100644
--- a/arch/x86/mm/iomap_32.c
+++ b/arch/x86/mm/iomap_32.c
@@ -59,6 +59,7 @@
unsigned long vaddr;
int idx, type;
+ preempt_disable();
pagefault_disable();
type = kmap_atomic_idx_push();
@@ -117,5 +118,6 @@
}
pagefault_enable();
+ preempt_enable();
}
EXPORT_SYMBOL_GPL(iounmap_atomic);
diff --git a/arch/xtensa/mm/highmem.c b/arch/xtensa/mm/highmem.c
index 8cfb71e..184cead 100644
--- a/arch/xtensa/mm/highmem.c
+++ b/arch/xtensa/mm/highmem.c
@@ -42,6 +42,7 @@
enum fixed_addresses idx;
unsigned long vaddr;
+ preempt_disable();
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
@@ -79,6 +80,7 @@
}
pagefault_enable();
+ preempt_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 9286a46..6aefcd0 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -65,6 +65,7 @@
static inline void *kmap_atomic(struct page *page)
{
+ preempt_disable();
pagefault_disable();
return page_address(page);
}
@@ -73,6 +74,7 @@
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 657fab4..c27dde7 100644
--- a/include/linux/io-mapping.h
+++ b/include/linux/io-mapping.h
@@ -141,6 +141,7 @@
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 @@
io_mapping_unmap_atomic(void __iomem *vaddr)
{
pagefault_enable();
+ preempt_enable();
}
/* Non-atomic map/unmap */