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authorDominik Dingel <dingel@linux.vnet.ibm.com>2013-10-31 13:01:16 +0400
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2013-10-31 19:52:58 +0400
commitbe39f1968e33ca641af120a2d659421ad2225dea (patch)
treea650e4ff8561174693a8ed19ccc97932b1883d60 /arch/s390
parent1db9e0513d7478f6c80ca0bc4f58f53fe49e27f8 (diff)
downloadlinux-be39f1968e33ca641af120a2d659421ad2225dea.tar.xz
s390/mm: page_table_realloc returns failure
There is a possible race between setting has_pgste and reallocation of the page_table, change the order to fix this. Also page_table_alloc_pgste can fail, in that case we need to backpropagte this as -ENOMEM to the caller of page_table_realloc. Based on a patch by Christian Borntraeger <borntraeger@de.ibm.com>. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/mm/pgtable.c21
1 files changed, 13 insertions, 8 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 94f37a9fb1e5..a9be08899b0c 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -1087,10 +1087,9 @@ again:
continue;
/* Allocate new page table with pgstes */
new = page_table_alloc_pgste(mm, addr);
- if (!new) {
- mm->context.has_pgste = 0;
- continue;
- }
+ if (!new)
+ return -ENOMEM;
+
spin_lock(&mm->page_table_lock);
if (likely((unsigned long *) pmd_deref(*pmd) == table)) {
/* Nuke pmd entry pointing to the "short" page table */
@@ -1128,13 +1127,15 @@ static unsigned long page_table_realloc_pud(struct mmu_gather *tlb,
if (pud_none_or_clear_bad(pud))
continue;
next = page_table_realloc_pmd(tlb, mm, pud, addr, next);
+ if (unlikely(IS_ERR_VALUE(next)))
+ return next;
} while (pud++, addr = next, addr != end);
return addr;
}
-static void page_table_realloc(struct mmu_gather *tlb, struct mm_struct *mm,
- unsigned long addr, unsigned long end)
+static unsigned long page_table_realloc(struct mmu_gather *tlb, struct mm_struct *mm,
+ unsigned long addr, unsigned long end)
{
unsigned long next;
pgd_t *pgd;
@@ -1145,7 +1146,11 @@ static void page_table_realloc(struct mmu_gather *tlb, struct mm_struct *mm,
if (pgd_none_or_clear_bad(pgd))
continue;
next = page_table_realloc_pud(tlb, mm, pgd, addr, next);
+ if (unlikely(IS_ERR_VALUE(next)))
+ return next;
} while (pgd++, addr = next, addr != end);
+
+ return 0;
}
/*
@@ -1165,9 +1170,9 @@ int s390_enable_sie(void)
/* split thp mappings and disable thp for future mappings */
thp_split_mm(mm);
/* Reallocate the page tables with pgstes */
- mm->context.has_pgste = 1;
tlb_gather_mmu(&tlb, mm, 0, TASK_SIZE);
- page_table_realloc(&tlb, mm, 0, TASK_SIZE);
+ if (!page_table_realloc(&tlb, mm, 0, TASK_SIZE))
+ mm->context.has_pgste = 1;
tlb_finish_mmu(&tlb, 0, TASK_SIZE);
up_write(&mm->mmap_sem);
return mm->context.has_pgste ? 0 : -ENOMEM;