xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[S390] fix tlb flushing vs. concurrent /proc accesses

Browse Source 
The tlb flushing code uses the mm_users field of the mm_struct to
decide if each page table entry needs to be flushed individually with
IPTE or if a global flush for the mm_struct is sufficient after all page
table updates have been done. The comment for mm_users says "How many
users with user space?" but the /proc code increases mm_users after it
found the process structure by pid without creating a new user process.
Which makes mm_users useless for the decision between the two tlb
flusing methods. The current code can be confused to not flush tlb
entries by a concurrent access to /proc files if e.g. a fork is in
progres. The solution for this problem is to make the tlb flushing
logic independent from the mm_users field.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
2010-08-24 09:26:21 +02:00
committed by Martin Schwidefsky
parent 7af048dc76
commit 050eef364a
8 changed files with 28 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
arch/s390/include/asm/tlbflush.h
View File

@@ -94,8 +94,12 @@ static inline void __tlb_flush_mm(struct mm_struct * mm)
static inline void __tlb_flush_mm_cond(struct mm_struct * mm)
{
if (atomic_read(&mm->mm_users) <= 1 && mm == current->active_mm)
spin_lock(&mm->page_table_lock);
if (mm->context.flush_mm) {
__tlb_flush_mm(mm);
mm->context.flush_mm = 0;
}
spin_unlock(&mm->page_table_lock);
}
/*