Re: [PATCH 06/17] Update the infiniband uverbs driver to use idr helper functions.

From: Doug Ledford
Date: Wed Sep 16 2015 - 14:40:24 EST


On 09/16/2015 01:50 PM, Lee Duncan wrote:
> Signed-off-by: Lee Duncan <lduncan@xxxxxxxx>

Looks OK to me. The setting of uobj->id is no longer under the lock,
but we won't succeed at an idr lookup until it is set, which means it
won't be found and can't be used in idr_remove_uobj() until after the
uobj->id is set regardless of the lock.

Acked-by: Doug Ledford <dledford@xxxxxxxxxx>

> ---
> drivers/infiniband/core/uverbs_cmd.c | 12 ++----------
> 1 file changed, 2 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
> index bbb02ffe87df..1e5b2a66a501 100644
> --- a/drivers/infiniband/core/uverbs_cmd.c
> +++ b/drivers/infiniband/core/uverbs_cmd.c
> @@ -120,24 +120,16 @@ static int idr_add_uobj(struct idr *idr, struct ib_uobject *uobj)
> {
> int ret;
>
> - idr_preload(GFP_KERNEL);
> - spin_lock(&ib_uverbs_idr_lock);
> -
> - ret = idr_alloc(idr, uobj, 0, 0, GFP_NOWAIT);
> + ret = idr_get_index(idr, &ib_uverbs_idr_lock, uobj);
> if (ret >= 0)
> uobj->id = ret;
>
> - spin_unlock(&ib_uverbs_idr_lock);
> - idr_preload_end();
> -
> return ret < 0 ? ret : 0;
> }
>
> void idr_remove_uobj(struct idr *idr, struct ib_uobject *uobj)
> {
> - spin_lock(&ib_uverbs_idr_lock);
> - idr_remove(idr, uobj->id);
> - spin_unlock(&ib_uverbs_idr_lock);
> + idr_put_index(idr, &ib_uverbs_idr_lock, uobj->id);
> }
>
> static struct ib_uobject *__idr_get_uobj(struct idr *idr, int id,
>


--
Doug Ledford <dledford@xxxxxxxxxx>
GPG KeyID: 0E572FDD


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