| Message ID | 20200801090825.5597-1-haowenchao22@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm, mempolicy: Check parameters first in kernel_get_mempolicy | expand |
On Sat, 1 Aug 2020 17:08:26 +0800 Wenchao Hao <haowenchao22@gmail.com> wrote: > Previous implement called untagged_addr before error check, while > if the error check failed and return EINVAL, the untagged_addr is > just useless work. > > ... > > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -1632,11 +1632,11 @@ static int kernel_get_mempolicy(int __user *policy, > int uninitialized_var(pval); > nodemask_t nodes; > > - addr = untagged_addr(addr); > - > if (nmask != NULL && maxnode < nr_node_ids) > return -EINVAL; > > + addr = untagged_addr(addr); > + > err = do_get_mempolicy(&pval, &nodes, addr, flags); > > if (err) Well, the compiler will surely avoid that useless work. But the code is better this way.
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 381320671677..dac0cd0df3e1 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1632,11 +1632,11 @@ static int kernel_get_mempolicy(int __user *policy, int uninitialized_var(pval); nodemask_t nodes; - addr = untagged_addr(addr); - if (nmask != NULL && maxnode < nr_node_ids) return -EINVAL; + addr = untagged_addr(addr); + err = do_get_mempolicy(&pval, &nodes, addr, flags); if (err)
Previous implement called untagged_addr before error check, while if the error check failed and return EINVAL, the untagged_addr is just useless work. Signed-off-by: Wenchao Hao <haowenchao22@gmail.com> --- mm/mempolicy.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)