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authorHugh Dickins <hugh@veritas.com>2005-10-29 21:16:38 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2005-10-30 00:40:42 -0400
commit8f5cd76c185a4c8aeb5fe1e560e3612bfc050c35 (patch)
tree42f9fc842005eda8d898998850a20c6afb5ce7e6 /arch/um/kernel
parenta7e4705b24e611574e5c23105005ffdff694fd58 (diff)
[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 <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/um/kernel')
-rw-r--r--arch/um/kernel/process_kern.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/um/kernel/process_kern.c b/arch/um/kernel/process_kern.c
index 0d73ceeece72..34b54a3e2132 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,
222 pud_t *pud; 222 pud_t *pud;
223 pmd_t *pmd; 223 pmd_t *pmd;
224 pte_t *pte; 224 pte_t *pte;
225 pte_t ptent;
225 226
226 if(task->mm == NULL) 227 if(task->mm == NULL)
227 return(ERR_PTR(-EINVAL)); 228 return(ERR_PTR(-EINVAL));
@@ -238,12 +239,13 @@ void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
238 return(ERR_PTR(-EINVAL)); 239 return(ERR_PTR(-EINVAL));
239 240
240 pte = pte_offset_kernel(pmd, addr); 241 pte = pte_offset_kernel(pmd, addr);
241 if(!pte_present(*pte)) 242 ptent = *pte;
243 if(!pte_present(ptent))
242 return(ERR_PTR(-EINVAL)); 244 return(ERR_PTR(-EINVAL));
243 245
244 if(pte_out != NULL) 246 if(pte_out != NULL)
245 *pte_out = *pte; 247 *pte_out = ptent;
246 return((void *) (pte_val(*pte) & PAGE_MASK) + (addr & ~PAGE_MASK)); 248 return((void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK));
247} 249}
248 250
249char *current_cmd(void) 251char *current_cmd(void)