[PATCH] mm: arm ready for split ptlock

[~andy/linux] / arch / arm / kernel / traps.c

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index baa09601a64ee5c908ad356b51bc8109ff574cdc..66e5a0516f23b31c61280dd9823b8837e217bbff 100644 (file)
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -483,29 +483,33 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
                unsigned long addr = regs->ARM_r2;
                struct mm_struct *mm = current->mm;
                pgd_t *pgd; pmd_t *pmd; pte_t *pte;
+               spinlock_t *ptl;
 
                regs->ARM_cpsr &= ~PSR_C_BIT;
-               spin_lock(&mm->page_table_lock);
+               down_read(&mm->mmap_sem);
                pgd = pgd_offset(mm, addr);
                if (!pgd_present(*pgd))
                        goto bad_access;
                pmd = pmd_offset(pgd, addr);
                if (!pmd_present(*pmd))
                        goto bad_access;
-               pte = pte_offset_map(pmd, addr);
-               if (!pte_present(*pte) || !pte_write(*pte))
+               pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+               if (!pte_present(*pte) || !pte_write(*pte)) {
+                       pte_unmap_unlock(pte, ptl);
                        goto bad_access;
+               }
                val = *(unsigned long *)addr;
                val -= regs->ARM_r0;
                if (val == 0) {
                        *(unsigned long *)addr = regs->ARM_r1;
                        regs->ARM_cpsr |= PSR_C_BIT;
                }
-               spin_unlock(&mm->page_table_lock);
+               pte_unmap_unlock(pte, ptl);
+               up_read(&mm->mmap_sem);
                return val;
 
                bad_access:
-               spin_unlock(&mm->page_table_lock);
+               up_read(&mm->mmap_sem);
                /* simulate a write access fault */
                do_DataAbort(addr, 15 + (1 << 11), regs);
                return -1;