From 8f5cd76c185a4c8aeb5fe1e560e3612bfc050c35 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Sat, 29 Oct 2005 18:16:38 -0700 Subject: [PATCH] [PATCH] mm: uml pte atomicity There's usually a good reason when a pte is examined without the lock; but it makes me nervous when the pointer is dereferenced more than once. Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/kernel/process_kern.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/um/kernel/process_kern.c b/arch/um/kernel/process_kern.c index 0d73ceeece7..34b54a3e213 100644 --- a/arch/um/kernel/process_kern.c +++ b/arch/um/kernel/process_kern.c @@ -222,6 +222,7 @@ void *um_virt_to_phys(struct task_struct *task, unsigned long addr, pud_t *pud; pmd_t *pmd; pte_t *pte; + pte_t ptent; if(task->mm == NULL) return(ERR_PTR(-EINVAL)); @@ -238,12 +239,13 @@ void *um_virt_to_phys(struct task_struct *task, unsigned long addr, return(ERR_PTR(-EINVAL)); pte = pte_offset_kernel(pmd, addr); - if(!pte_present(*pte)) + ptent = *pte; + if(!pte_present(ptent)) return(ERR_PTR(-EINVAL)); if(pte_out != NULL) - *pte_out = *pte; - return((void *) (pte_val(*pte) & PAGE_MASK) + (addr & ~PAGE_MASK)); + *pte_out = ptent; + return((void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK)); } char *current_cmd(void) -- 2.20.1