From: Leon Romanovsky <leon@kernel.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-rdma@vger.kernel.org, Artemy Kovalyov <artemyko@mellanox.com>
Subject: Re: [PATCH 2/6] RDMA/mlx5: Fix a race with mlx5_ib_update_xlt on an implicit MR
Date: Wed, 2 Oct 2019 18:41:14 +0300 [thread overview]
Message-ID: <20191002154114.GF5855@unreal> (raw)
In-Reply-To: <20191002143928.GE17152@ziepe.ca>
On Wed, Oct 02, 2019 at 11:39:28AM -0300, Jason Gunthorpe wrote:
> On Wed, Oct 02, 2019 at 11:18:26AM +0300, Leon Romanovsky wrote:
> > > @@ -202,15 +225,22 @@ static void mr_leaf_free_action(struct work_struct *work)
> > > struct ib_umem_odp *odp = container_of(work, struct ib_umem_odp, work);
> > > int idx = ib_umem_start(odp) >> MLX5_IMR_MTT_SHIFT;
> > > struct mlx5_ib_mr *mr = odp->private, *imr = mr->parent;
> > > + struct ib_umem_odp *odp_imr = to_ib_umem_odp(imr->umem);
> > > + int srcu_key;
> > >
> > > mr->parent = NULL;
> > > synchronize_srcu(&mr->dev->mr_srcu);
> >
> > Are you sure that this line is still needed?
>
> Yes, in this case the mr->parent is the SRCU 'update' and it blocks
> seeing this MR in the pagefault handler.
>
> It is necessary before calling ib_umem_odp_release below that frees
> the memory
sorry for not being clear, I thought that synchronize_srcu() should be
moved after your read_lock/unlock additions to reuse grace period.
Thanks
>
> Jason
next prev parent reply other threads:[~2019-10-02 15:41 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-01 15:38 [PATCH -rc 0/6] Bug fixes for odp Jason Gunthorpe
2019-10-01 15:38 ` [PATCH 1/6] RDMA/mlx5: Do not allow rereg of a ODP MR Jason Gunthorpe
2019-10-01 15:38 ` [PATCH 2/6] RDMA/mlx5: Fix a race with mlx5_ib_update_xlt on an implicit MR Jason Gunthorpe
2019-10-02 8:18 ` Leon Romanovsky
2019-10-02 14:39 ` Jason Gunthorpe
2019-10-02 15:41 ` Leon Romanovsky [this message]
2019-10-03 12:48 ` Jason Gunthorpe
2019-10-01 15:38 ` [PATCH 3/6] RDMA/odp: Lift umem_mutex out of ib_umem_odp_unmap_dma_pages() Jason Gunthorpe
2019-10-01 15:38 ` [PATCH 4/6] RDMA/mlx5: Order num_pending_prefetch properly with synchronize_srcu Jason Gunthorpe
2019-10-01 15:38 ` [PATCH 5/6] RDMA/mlx5: Put live in the correct place for ODP MRs Jason Gunthorpe
2019-10-01 15:38 ` [PATCH 6/6] RDMA/mlx5: Add missing synchronize_srcu() for MW cases Jason Gunthorpe
2019-10-03 8:54 ` Leon Romanovsky
2019-10-03 12:33 ` Jason Gunthorpe
2019-10-04 18:55 ` [PATCH -rc 0/6] Bug fixes for odp Jason Gunthorpe
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