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[PATCH] mm: pagefault_{disable,enable}()

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Introduce pagefault_{disable,enable}() and use these where previously we did
manual preempt increments/decrements to make the pagefault handler do the
atomic thing.

Currently they still rely on the increased preempt count, but do not rely on
the disabled preemption, this might go away in the future.

(NOTE: the extra barrier() in pagefault_disable might fix some holes on
       machines which have too many registers for their own good)

[heiko.carstens@de.ibm.com: s390 fix]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Nick Piggin <npiggin@suse.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Peter Zijlstra
2006-12-06 20:32:20 -08:00
committed by Linus Torvalds
parent 6edaf68a87
commit a866374aec
17 changed files with 88 additions and 62 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/asm-frv/highmem.h
+2 -3
View File
@@ -115,7 +115,7 @@ static inline void *kmap_atomic(struct page *page, enum km_type type)
{
unsigned long paddr;
inc_preempt_count();
pagefault_disable();
paddr = page_to_phys(page);
switch (type) {
@@ -170,8 +170,7 @@ static inline void kunmap_atomic(void *kvaddr, enum km_type type)
default:
BUG();
}
dec_preempt_count();
preempt_check_resched();
pagefault_enable();
}
#endif /* !__ASSEMBLY__ */
include/asm-generic/futex.h
+2 -2
View File
@@ -21,7 +21,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
inc_preempt_count();
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
@@ -33,7 +33,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
ret = -ENOSYS;
}
dec_preempt_count();
pagefault_enable();
if (!ret) {
switch (cmp) {
include/asm-i386/futex.h
+2 -2
View File
@@ -56,7 +56,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
inc_preempt_count();
pagefault_disable();
if (op == FUTEX_OP_SET)
__futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
@@ -88,7 +88,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
}
}
dec_preempt_count();
pagefault_enable();
if (!ret) {
switch (cmp) {
include/asm-ia64/futex.h
+2 -2
View File
@@ -59,7 +59,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
inc_preempt_count();
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
@@ -83,7 +83,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
ret = -ENOSYS;
}
dec_preempt_count();
pagefault_enable();
if (!ret) {
switch (cmp) {
include/asm-mips/futex.h
+2 -2
View File
@@ -88,7 +88,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
inc_preempt_count();
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
@@ -115,7 +115,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
ret = -ENOSYS;
}
dec_preempt_count();
pagefault_enable();
if (!ret) {
switch (cmp) {
include/asm-parisc/futex.h
+2 -2
View File
@@ -21,7 +21,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
inc_preempt_count();
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
@@ -33,7 +33,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
ret = -ENOSYS;
}
dec_preempt_count();
pagefault_enable();
if (!ret) {
switch (cmp) {
include/asm-powerpc/futex.h
+2 -2
View File
@@ -43,7 +43,7 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
inc_preempt_count();
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
@@ -65,7 +65,7 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
ret = -ENOSYS;
}
dec_preempt_count();
pagefault_enable();
if (!ret) {
switch (cmp) {
include/asm-ppc/highmem.h
+3 -5
View File
@@ -79,7 +79,7 @@ static inline void *kmap_atomic(struct page *page, enum km_type type)
unsigned long vaddr;
/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
inc_preempt_count();
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
@@ -101,8 +101,7 @@ static inline void kunmap_atomic(void *kvaddr, enum km_type type)
unsigned int idx = type + KM_TYPE_NR*smp_processor_id();
if (vaddr < KMAP_FIX_BEGIN) { // FIXME
dec_preempt_count();
preempt_check_resched();
pagefault_enable();
return;
}
@@ -115,8 +114,7 @@ static inline void kunmap_atomic(void *kvaddr, enum km_type type)
pte_clear(&init_mm, vaddr, kmap_pte+idx);
flush_tlb_page(NULL, vaddr);
#endif
dec_preempt_count();
preempt_check_resched();
pagefault_enable();
}
static inline struct page *kmap_atomic_to_page(void *ptr)
include/asm-sparc64/futex.h
+2 -2
View File
@@ -45,7 +45,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
oparg = 1 << oparg;
inc_preempt_count();
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
@@ -67,7 +67,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
ret = -ENOSYS;
}
dec_preempt_count();
pagefault_enable();
if (!ret) {
switch (cmp) {
include/asm-x86_64/futex.h
+2 -2
View File
@@ -55,7 +55,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
inc_preempt_count();
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
@@ -78,7 +78,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
ret = -ENOSYS;
}
dec_preempt_count();
pagefault_enable();
if (!ret) {
switch (cmp) {
include/linux/uaccess.h
+37 -2
View File
@@ -1,8 +1,43 @@
#ifndef __LINUX_UACCESS_H__
#define __LINUX_UACCESS_H__
#include <linux/preempt.h>
#include <asm/uaccess.h>
/*
* These routines enable/disable the pagefault handler in that
* it will not take any locks and go straight to the fixup table.
*
* They have great resemblance to the preempt_disable/enable calls
* and in fact they are identical; this is because currently there is
* no other way to make the pagefault handlers do this. So we do
* disable preemption but we don't necessarily care about that.
*/
static inline void pagefault_disable(void)
{
inc_preempt_count();
/*
* make sure to have issued the store before a pagefault
* can hit.
*/
barrier();
}
static inline void pagefault_enable(void)
{
/*
* make sure to issue those last loads/stores before enabling
* the pagefault handler again.
*/
barrier();
dec_preempt_count();
/*
* make sure we do..
*/
barrier();
preempt_check_resched();
}
#ifndef ARCH_HAS_NOCACHE_UACCESS
static inline unsigned long __copy_from_user_inatomic_nocache(void *to,
@@ -35,9 +70,9 @@ static inline unsigned long __copy_from_user_nocache(void *to,
({ \
long ret; \
\
inc_preempt_count(); \
pagefault_disable(); \
ret = __get_user(retval, addr); \
dec_preempt_count(); \
pagefault_enable(); \
ret; \
})