Re: [PATCH rdma-next] IB/mlx5: Symmetric ib_alloc/dealloc_device

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sun, Dec 09, 2018 at 11:11:20AM -0700, Jason Gunthorpe wrote:
> On Sun, Dec 09, 2018 at 08:07:15PM +0200, Leon Romanovsky wrote:
> > On Sun, Dec 09, 2018 at 07:01:15PM +0200, Leon Romanovsky wrote:
> > > On Sun, Dec 09, 2018 at 09:45:46AM -0700, Jason Gunthorpe wrote:
> > > > On Sun, Dec 09, 2018 at 10:56:46AM +0200, Leon Romanovsky wrote:
> > > > > On Thu, Dec 06, 2018 at 08:46:42PM -0700, Jason Gunthorpe wrote:
> > > > > > On Wed, Dec 05, 2018 at 04:06:12PM +0200, Leon Romanovsky wrote:
> > > > > > > From: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
> > > > > > >
> > > > > > > __mlx5_ib_add didn't allocate ib_device, this means __mlx5_ib_remove
> > > > > > > shouldn't free it, hence make the alloc/dealloc symmetric.
> > > > > > >
> > > > > > > Put dealloc_device outside __mlx5_ib_remove and convert __mlx5_ib_add
> > > > > > > to return int value rather than dev pointer on success and null on failure.
> > > > > > >
> > > > > > > Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
> > > > > > > Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
> > > > > > >  drivers/infiniband/hw/mlx5/ib_rep.c  |  9 +++++++--
> > > > > > >  drivers/infiniband/hw/mlx5/main.c    | 23 +++++++++++++++--------
> > > > > > >  drivers/infiniband/hw/mlx5/mlx5_ib.h |  4 ++--
> > > > > > >  3 files changed, 24 insertions(+), 12 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/infiniband/hw/mlx5/ib_rep.c b/drivers/infiniband/hw/mlx5/ib_rep.c
> > > > > > > index 8a682d86d634..5ee383b0fc32 100644
> > > > > > > +++ b/drivers/infiniband/hw/mlx5/ib_rep.c
> > > > > > > @@ -61,6 +61,7 @@ static int
> > > > > > >  mlx5_ib_vport_rep_load(struct mlx5_core_dev *dev, struct mlx5_eswitch_rep *rep)
> > > > > > >  {
> > > > > > >  	struct mlx5_ib_dev *ibdev;
> > > > > > > +	int err;
> > > > > > >
> > > > > > >  	ibdev = (struct mlx5_ib_dev *)ib_alloc_device(sizeof(*ibdev));
> > > > > >
> > > > > > This should be container_of not a cast.
> > > > >
> > > > > I'm preparing v1 now and not sure how to handle this comment.
> > > > > First, it wasn't part of this patch, second (more important),
> > > > > ibdev is declared as pointer of mlx5_ib_dev, so unclear how
> > > > > do you see container_of be used here with uninitialized ibdev.
> > > >
> > > > ibdev = container_of(ib_alloc_device(sizeof(*ibdev)), struct
> > > >                      mlx6_ib_dev, ib_dev);
> > > >
> > > > And this whole pattern really should be a standard macro:
> > >
> > > Interesting, I worked on something similar right now, except the fact
> > > that ib_alloc_device() can return NULL.
>
> The build_bug_on takes care of the NULL issue.

I doubt about that. NULL will be returned at the runtime if kmalloc fails,
but build_bug_on is checked in compilation phase.

>
> > I actually think that the cleanest solution will be to move kzalloc to
> > the drivers and change ib_alloc_device (need to rename too). It will
> > allow us to get rid of IB wrapper and make device allocation scheme
> > be similar to other part of kernel.
>
> No, this is a kref'd structure with the core code calling kfree, so it
> is saner for the core code to control the allocation.
>
> In both cases the ibdev must be at offset 0, and really, it still
> needs the macro to enforce that..

I saw it, but disliked the aesthetic side of your proposal.

>
> Jason

Attachment: signature.asc
Description: PGP signature


[Index of Archives]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Photo]     [Yosemite News]     [Yosemite Photos]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux