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KVM: s390/mm: Fix page table locking vs. split pmd lock

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commit ec66ad66a0 (s390/mm: enable
split page table lock for PMD level) activated the split pmd lock
for s390. Turns out that we missed one place: We also have to take
the pmd lock instead of the page table lock when we reallocate the
page tables (==> changing entries in the PMD) during sie enablement.

Cc: stable@vger.kernel.org # 3.15+
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Christian Borntraeger 2014-07-25 14:23:29 +02:00 committed by Martin Schwidefsky
parent a94fa15429
commit 55e4283c3e
1 changed files with 3 additions and 2 deletions
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5
arch/s390/mm/pgtable.c
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@ -1279,6 +1279,7 @@ static unsigned long page_table_realloc_pmd(struct mmu_gather *tlb,
{
unsigned long next, *table, *new;
struct page *page;
spinlock_t *ptl;
pmd_t *pmd;
pmd = pmd_offset(pud, addr);
@ -1296,7 +1297,7 @@ again:
if (!new)
return -ENOMEM;
spin_lock(&mm->page_table_lock);
ptl = pmd_lock(mm, pmd);
if (likely((unsigned long *) pmd_deref(*pmd) == table)) {
/* Nuke pmd entry pointing to the "short" page table */
pmdp_flush_lazy(mm, addr, pmd);
@ -1310,7 +1311,7 @@ again:
page_table_free_rcu(tlb, table);
new = NULL;
}
spin_unlock(&mm->page_table_lock);
spin_unlock(ptl);
if (new) {
page_table_free_pgste(new);
goto again;