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authorHeiko Carstens <heiko.carstens@de.ibm.com>2012-10-22 15:58:26 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2012-11-13 11:02:28 +0100
commit516bad44b9f3bdcb0be6be0252b7557bf7a149e4 (patch)
treea74b68861b98a51bc7a9197159bd96d51b2cc7d8
parentd55c4c613fc4d4ad2ba0fc6fa2b57176d420f7e4 (diff)
downloadop-kernel-dev-516bad44b9f3bdcb0be6be0252b7557bf7a149e4.zip
op-kernel-dev-516bad44b9f3bdcb0be6be0252b7557bf7a149e4.tar.gz
s390/gup: fix access_ok() usage in __get_user_pages_fast()
access_ok() returns always "true" on s390. Therefore all access_ok() invocations are rather pointless. However when walking page tables we need to make sure that everything is within bounds of the ASCE limit of the task's address space. So remove the access_ok() call and add the same check we have in get_user_pages_fast(). Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/mm/gup.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index 16fb3c1..1f5315d1 100644
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -180,8 +180,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
addr = start;
len = (unsigned long) nr_pages << PAGE_SHIFT;
end = start + len;
- if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ,
- (void __user *)start, len)))
+ if ((end < start) || (end > TASK_SIZE))
return 0;
local_irq_save(flags);
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