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Message-ID: <8b8ed0fa-1fdb-3cb5-4800-1d9defe9553f@gmail.com>
Date:   Fri, 19 May 2023 12:08:09 -0500
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Subject: Re: [PATCH for-next v5 4/7] RDMA/rxe: Add page invalidation support
Content-Language: en-US
To:     Daisuke Matsuda <matsuda-daisuke@fujitsu.com>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        Leon Romanovsky <leonro@nvidia.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Zhu Yanjun <zyjzyj2000@gmail.com>
References: <cover.1684397037.git.matsuda-daisuke@fujitsu.com>
 <6e9d5e2d1b2a63385d1e4fc2a74c3b11d4909842.1684397037.git.matsuda-daisuke@fujitsu.com>
Cc:     LKML <linux-kernel@vger.kernel.org>, rpearsonhpe@gmail.com,
        Xiao Yang <yangx.jy@fujitsu.com>,
        "lizhijian@fujitsu.com" <lizhijian@fujitsu.com>,
        "y-goto@fujitsu.com" <y-goto@fujitsu.com>
From:   Bob Pearson <rpearsonhpe@gmail.com>
In-Reply-To: <6e9d5e2d1b2a63385d1e4fc2a74c3b11d4909842.1684397037.git.matsuda-daisuke@fujitsu.com>
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Precedence: bulk

On 5/18/23 23:07, Daisuke Matsuda wrote:
> On page invalidation, an MMU notifier callback is invoked to unmap DMA
> addresses and update the driver page table(umem_odp->dma_list). It also
> set the corresponding entries in MR xarray to NULL to prevent any access.
> The callback is registered when an ODP-enabled MR is created.
> 
> Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
> ---
>  drivers/infiniband/sw/rxe/Makefile  |  2 ++
>  drivers/infiniband/sw/rxe/rxe_odp.c | 56 +++++++++++++++++++++++++++++
>  2 files changed, 58 insertions(+)
>  create mode 100644 drivers/infiniband/sw/rxe/rxe_odp.c
> 
> diff --git a/drivers/infiniband/sw/rxe/Makefile b/drivers/infiniband/sw/rxe/Makefile
> index 5395a581f4bb..93134f1d1d0c 100644
> --- a/drivers/infiniband/sw/rxe/Makefile
> +++ b/drivers/infiniband/sw/rxe/Makefile
> @@ -23,3 +23,5 @@ rdma_rxe-y := \
>  	rxe_task.o \
>  	rxe_net.o \
>  	rxe_hw_counters.o
> +
> +rdma_rxe-$(CONFIG_INFINIBAND_ON_DEMAND_PAGING) += rxe_odp.o
> diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/infiniband/sw/rxe/rxe_odp.c
> new file mode 100644
> index 000000000000..b69b25e0fef6
> --- /dev/null
> +++ b/drivers/infiniband/sw/rxe/rxe_odp.c
> @@ -0,0 +1,56 @@
> +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> +/*
> + * Copyright (c) 2022-2023 Fujitsu Ltd. All rights reserved.
> + */
> +
> +#include <linux/hmm.h>
> +
> +#include <rdma/ib_umem_odp.h>
> +
> +#include "rxe.h"
> +
> +static void rxe_mr_unset_xarray(struct rxe_mr *mr, unsigned long start,
> +				unsigned long end)
> +{
> +	unsigned long lower, upper, idx;
> +
> +	lower = rxe_mr_iova_to_index(mr, start);
> +	upper = rxe_mr_iova_to_index(mr, end);
> +
> +	/* make elements in xarray NULL */
> +	spin_lock(&mr->page_list.xa_lock);
> +	for (idx = lower; idx <= upper; idx++)
> +		__xa_erase(&mr->page_list, idx);
> +	spin_unlock(&mr->page_list.xa_lock);
> +}
> +
> +static bool rxe_ib_invalidate_range(struct mmu_interval_notifier *mni,
> +				    const struct mmu_notifier_range *range,
> +				    unsigned long cur_seq)
> +{
> +	struct ib_umem_odp *umem_odp =
> +		container_of(mni, struct ib_umem_odp, notifier);
> +	struct rxe_mr *mr = umem_odp->private;
> +	unsigned long start, end;
> +
> +	if (!mmu_notifier_range_blockable(range))
> +		return false;
> +
> +	mutex_lock(&umem_odp->umem_mutex);
> +	mmu_interval_set_seq(mni, cur_seq);
> +
> +	start = max_t(u64, ib_umem_start(umem_odp), range->start);
> +	end = min_t(u64, ib_umem_end(umem_odp), range->end);
> +
> +	rxe_mr_unset_xarray(mr, start, end);
> +
> +	/* update umem_odp->dma_list */
> +	ib_umem_odp_unmap_dma_pages(umem_odp, start, end);
> +
> +	mutex_unlock(&umem_odp->umem_mutex);
> +	return true;
> +}
> +
> +const struct mmu_interval_notifier_ops rxe_mn_ops = {
> +	.invalidate = rxe_ib_invalidate_range,
> +};

Looks good.

Reviewed-by: Bob Pearson <rpearsonhpe@gmail.com>