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authorChristian Borntraeger <borntraeger@de.ibm.com>2014-07-25 14:23:29 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2014-08-01 11:16:23 +0200
commit55e4283c3eb1d850893f645dd695c9c75d5fa1fc (patch)
tree73b921638494fa3923c94a3930b48bb4f3b20242 /arch/s390/mm
parenta94fa154291bb11b1537ac2ff1ae2fd28428e054 (diff)
downloadlinux-55e4283c3eb1d850893f645dd695c9c75d5fa1fc.tar.gz
KVM: s390/mm: Fix page table locking vs. split pmd lock
commit ec66ad66a0de87866be347b5ecc83bd46427f53b (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>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/pgtable.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 37b8241ec784..f90ad8592b36 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -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;