[PATCH 7/9] md: use kvmalloc rather than opencoded variant

From: Michal Hocko
Date: Mon Jan 30 2017 - 04:53:03 EST


From: Michal Hocko <mhocko@xxxxxxxx>

copy_params uses kmalloc with vmalloc fallback. We already have a helper
for that - kvmalloc. This caller requires GFP_NOIO semantic so it hasn't
been converted with many others by previous patches. All we need to
achieve this semantic is to use the scope memalloc_noio_{save,restore}
around kvmalloc.

Cc: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
---
drivers/md/dm-ioctl.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index a5a9b17f0f7f..dbf5b981f7d7 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1698,6 +1698,7 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
struct dm_ioctl *dmi;
int secure_data;
const size_t minimum_data_size = offsetof(struct dm_ioctl, data);
+ unsigned noio_flag;

if (copy_from_user(param_kernel, user, minimum_data_size))
return -EFAULT;
@@ -1720,15 +1721,9 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
* Use kmalloc() rather than vmalloc() when we can.
*/
dmi = NULL;
- if (param_kernel->data_size <= KMALLOC_MAX_SIZE)
- dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
-
- if (!dmi) {
- unsigned noio_flag;
- noio_flag = memalloc_noio_save();
- dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_HIGH | __GFP_HIGHMEM, PAGE_KERNEL);
- memalloc_noio_restore(noio_flag);
- }
+ noio_flag = memalloc_noio_save();
+ dmi = kvmalloc(param_kernel->data_size, GFP_KERNEL);
+ memalloc_noio_restore(noio_flag);

if (!dmi) {
if (secure_data && clear_user(user, param_kernel->data_size))
--
2.11.0