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SubjectRe: [PATCH] md: simplify free_params for kmalloc vs vmalloc fallback
Acked-by: Mikulas Patocka <mpatocka@redhat.com>

BTW. we could also use kvmalloc to complement kvfree, proposed here:
https://www.redhat.com/archives/dm-devel/2015-July/msg00046.html

Mikulas

On Thu, 28 Apr 2016, Michal Hocko wrote:

> From: Michal Hocko <mhocko@suse.com>
>
> Use kvfree rather than DM_PARAMS_[KV]MALLOC specific param flags.
>
> Cc: Shaohua Li <shli@kernel.org>
> Cc: Mikulas Patocka <mpatocka@redhat.com>
> Cc: dm-devel@redhat.com
> Signed-off-by: Michal Hocko <mhocko@suse.com>
> ---
> Hi,
> this is a rebase on top of dropped "dm: clean up GFP_NIO usage" which
> should be dropped as per the feedback from Mikulas.
>
> drivers/md/dm-ioctl.c | 16 +++-------------
> 1 file changed, 3 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
> index 2c7ca258c4e4..e66e5b43bc18 100644
> --- a/drivers/md/dm-ioctl.c
> +++ b/drivers/md/dm-ioctl.c
> @@ -1670,19 +1670,14 @@ static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
> return r;
> }
>
> -#define DM_PARAMS_KMALLOC 0x0001 /* Params alloced with kmalloc */
> -#define DM_PARAMS_VMALLOC 0x0002 /* Params alloced with vmalloc */
> -#define DM_WIPE_BUFFER 0x0010 /* Wipe input buffer before returning from ioctl */
> +#define DM_WIPE_BUFFER 0x0001 /* Wipe input buffer before returning from ioctl */
>
> static void free_params(struct dm_ioctl *param, size_t param_size, int param_flags)
> {
> if (param_flags & DM_WIPE_BUFFER)
> memset(param, 0, param_size);
>
> - if (param_flags & DM_PARAMS_KMALLOC)
> - kfree(param);
> - if (param_flags & DM_PARAMS_VMALLOC)
> - vfree(param);
> + kvfree(param);
> }
>
> static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kernel,
> @@ -1714,19 +1709,14 @@ 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) {
> + if (param_kernel->data_size <= KMALLOC_MAX_SIZE)
> dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
> - if (dmi)
> - *param_flags |= DM_PARAMS_KMALLOC;
> - }
>
> 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);
> - if (dmi)
> - *param_flags |= DM_PARAMS_VMALLOC;
> }
>
> if (!dmi) {
> --
> 2.8.0.rc3
>

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