diff options
| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2007-07-21 17:11:35 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-21 18:37:14 -0700 |
| commit | 9585116ba09f1d8c52d0a1346e20bb9d443e9c02 (patch) | |
| tree | c3380b477754d3d2d77fa8dbd08f0b0d08fdcadf | |
| parent | a2900975ef3f1df33c83e750cc1e490de3374ca8 (diff) | |
i386: fix iounmap's use of vm_struct's size field
get_vm_area always returns an area with an adjacent guard page. That guard
page is included in vm_struct.size. iounmap uses vm_struct.size to
determine how much address space needs to have change_page_attr applied to
it, which will BUG if applied to the guard page.
This patch adds a helper function - get_vm_area_size() in linux/vmalloc.h -
to return the actual size of a vm area, and uses it to make iounmap do the
right thing. There are probably other places which should be using
get_vm_area_size().
Thanks to Dave Young <hidave.darkstar@gmail.com> for debugging the
problem.
[ Andi, it wasn't clear to me whether x86_64 needs the same fix. ]
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Dave Young <hidave.darkstar@gmail.com>
Cc: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/i386/mm/ioremap.c | 2 | ||||
| -rw-r--r-- | include/linux/vmalloc.h | 7 |
2 files changed, 8 insertions, 1 deletions
diff --git a/arch/i386/mm/ioremap.c b/arch/i386/mm/ioremap.c index fff08ae7b5e..0b278315d73 100644 --- a/arch/i386/mm/ioremap.c +++ b/arch/i386/mm/ioremap.c @@ -196,7 +196,7 @@ void iounmap(volatile void __iomem *addr) /* Reset the direct mapping. Can block */ if ((p->flags >> 20) && p->phys_addr < virt_to_phys(high_memory) - 1) { change_page_attr(virt_to_page(__va(p->phys_addr)), - p->size >> PAGE_SHIFT, + get_vm_area_size(p) >> PAGE_SHIFT, PAGE_KERNEL); global_flush_tlb(); } diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index c2b10cae5da..89338b468d0 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -58,6 +58,13 @@ void vmalloc_sync_all(void); /* * Lowlevel-APIs (not for driver use!) */ + +static inline size_t get_vm_area_size(const struct vm_struct *area) +{ + /* return actual size without guard page */ + return area->size - PAGE_SIZE; +} + extern struct vm_struct *get_vm_area(unsigned long size, unsigned long flags); extern struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags, unsigned long start, unsigned long end); |