Re: [PATCH for-next v3 4/9] RDMA/rxe: Add ib_alloc_mw and ib_dealloc_mw verbs

[Leon Romanovsky <leon@kernel.org>]

On Wed, Apr 21, 2021 at 01:54:49PM +0800, Zhu Yanjun wrote:
> On Wed, Apr 21, 2021 at 1:20 PM Bob Pearson <rpearsonhpe@gmail.com> wrote:
> >
> > Add ib_alloc_mw and ib_dealloc_mw verbs APIs.
> >
> > Added new file rxe_mw.c focused on MWs.
> > Changed the 8 bit random key generator.
> > Added a cleanup routine for MWs.
> > Added verbs routines to ib_device_ops.
> >
> > Signed-off-by: Bob Pearson <rpearson@hpe.com>
> > ---
> >  drivers/infiniband/sw/rxe/Makefile    |  1 +
> >  drivers/infiniband/sw/rxe/rxe_loc.h   |  6 +++
> >  drivers/infiniband/sw/rxe/rxe_mr.c    | 20 +++++-----
> >  drivers/infiniband/sw/rxe/rxe_mw.c    | 53 +++++++++++++++++++++++++++
> >  drivers/infiniband/sw/rxe/rxe_pool.c  |  1 +
> >  drivers/infiniband/sw/rxe/rxe_verbs.c |  3 ++
> >  drivers/infiniband/sw/rxe/rxe_verbs.h |  2 +
> >  7 files changed, 75 insertions(+), 11 deletions(-)
> >  create mode 100644 drivers/infiniband/sw/rxe/rxe_mw.c
> >
> > diff --git a/drivers/infiniband/sw/rxe/Makefile b/drivers/infiniband/sw/rxe/Makefile
> > index 66af72dca759..1e24673e9318 100644
> > --- a/drivers/infiniband/sw/rxe/Makefile
> > +++ b/drivers/infiniband/sw/rxe/Makefile
> > @@ -15,6 +15,7 @@ rdma_rxe-y := \
> >         rxe_qp.o \
> >         rxe_cq.o \
> >         rxe_mr.o \
> > +       rxe_mw.o \
> >         rxe_opcode.o \
> >         rxe_mmap.o \
> >         rxe_icrc.o \
> > diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
> > index ef8061d2fbe0..edf575930a98 100644
> > --- a/drivers/infiniband/sw/rxe/rxe_loc.h
> > +++ b/drivers/infiniband/sw/rxe/rxe_loc.h
> > @@ -76,6 +76,7 @@ enum copy_direction {
> >         from_mr_obj,
> >  };
> >
> > +u8 rxe_get_next_key(u32 last_key);
> >  void rxe_mr_init_dma(struct rxe_pd *pd, int access, struct rxe_mr *mr);
> >
> >  int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
> > @@ -106,6 +107,11 @@ void rxe_mr_cleanup(struct rxe_pool_entry *arg);
> >
> >  int advance_dma_data(struct rxe_dma_info *dma, unsigned int length);
> >
> > +/* rxe_mw.c */
> > +int rxe_alloc_mw(struct ib_mw *ibmw, struct ib_udata *udata);
> > +int rxe_dealloc_mw(struct ib_mw *ibmw);
> > +void rxe_mw_cleanup(struct rxe_pool_entry *arg);
> > +
> >  /* rxe_net.c */
> >  void rxe_loopback(struct sk_buff *skb);
> >  int rxe_send(struct rxe_pkt_info *pkt, struct sk_buff *skb);
> > diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
> > index 9f63947bab12..7f2cfc1ce659 100644
> > --- a/drivers/infiniband/sw/rxe/rxe_mr.c
> > +++ b/drivers/infiniband/sw/rxe/rxe_mr.c
> > @@ -7,19 +7,17 @@
> >  #include "rxe.h"
> >  #include "rxe_loc.h"
> >
> > -/*
> > - * lfsr (linear feedback shift register) with period 255
> > +/* Return a random 8 bit key value that is
> > + * different than the last_key. Set last_key to -1
> > + * if this is the first key for an MR or MW
> >   */
> > -static u8 rxe_get_key(void)
> > +u8 rxe_get_next_key(u32 last_key)
> >  {
> > -       static u32 key = 1;
> > -
> > -       key = key << 1;
> > -
> > -       key |= (0 != (key & 0x100)) ^ (0 != (key & 0x10))
> > -               ^ (0 != (key & 0x80)) ^ (0 != (key & 0x40));
> > +       u8 key;
> >
> > -       key &= 0xff;
> > +       do {
> > +               get_random_bytes(&key, 1);
> > +       } while (key == last_key);
> >
> >         return key;
> >  }
> > @@ -47,7 +45,7 @@ int mr_check_range(struct rxe_mr *mr, u64 iova, size_t length)
> >
> >  static void rxe_mr_init(int access, struct rxe_mr *mr)
> >  {
> > -       u32 lkey = mr->pelem.index << 8 | rxe_get_key();
> > +       u32 lkey = mr->pelem.index << 8 | rxe_get_next_key(-1);
> >         u32 rkey = (access & IB_ACCESS_REMOTE) ? lkey : 0;
> >
> >         mr->ibmr.lkey = lkey;
> > diff --git a/drivers/infiniband/sw/rxe/rxe_mw.c b/drivers/infiniband/sw/rxe/rxe_mw.c
> > new file mode 100644
> > index 000000000000..69128e298d44
> > --- /dev/null
> > +++ b/drivers/infiniband/sw/rxe/rxe_mw.c
> > @@ -0,0 +1,53 @@
> > +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> > +/*
> > + * Copyright (c) 2020 Hewlett Packard Enterprise, Inc. All rights reserved.
> > + */
> 
> The above is different with the following:
> "
> // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> /*
>  * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
>  * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
>  */
> "
> 
> One is Hewlett Packard Enterprise, Inc, the other is Mellanox Technologies Ltd.
> 
> I am not sure whether it is a legal problem.
>

It is not an issue, because Bob created new file together with adding
enough new code in it.

Thanks