On Sun, Oct 13, 2024 3:16 PM Zhu Yanjun wrote:
> 在 2024/10/9 9:59, Daisuke Matsuda 写道:
> > 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
> > sets 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@xxxxxxxxxxx>
> > ---
> > drivers/infiniband/sw/rxe/Makefile | 2 +
> > drivers/infiniband/sw/rxe/rxe_odp.c | 57 +++++++++++++++++++++++++++++
> > 2 files changed, 59 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..ea55b79be0c6
> > --- /dev/null
> > +++ b/drivers/infiniband/sw/rxe/rxe_odp.c
> > @@ -0,0 +1,57 @@
> > +// 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 upper = rxe_mr_iova_to_index(mr, end - 1);
> > + unsigned long lower = rxe_mr_iova_to_index(mr, start);
> > + void *entry;
> > +
> > + XA_STATE(xas, &mr->page_list, lower);
> > +
> > + /* make elements in xarray NULL */
> > + xas_lock(&xas);
> > + xas_for_each(&xas, entry, upper)
> > + xas_store(&xas, NULL);
> > + xas_unlock(&xas);
> > +}
> > +
> > +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);
>
> guard(mutex)(&umem_odp->umem_mutex);
>
> It seems that the above is more popular.
Thanks for the comment.
I have no objection to your suggestion since the increasing number of
kernel components use "guard(mutex)" syntax these days, but I would rather
suggest making the change to the whole infiniband subsystem at once because
there are multiple mutex lock/unlock pairs to be converted.
Regards,
Daisuke Matsuda
>
> Zhu Yanjun
> > + 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,
> > +};
