> -----Original Message-----
> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Monday, 30 January 2023 14:29
> To: Bernard Metzler <BMT@xxxxxxxxxxxxxx>
> Cc: linux-rdma@xxxxxxxxxxxxxxx; leonro@xxxxxxxxxx; apopple@xxxxxxxxxx
> Subject: [EXTERNAL] Re: [PATCH] RDMA/siw: Fix user page pinning accounting
>
> On Mon, Jan 30, 2023 at 02:28:04PM +0100, Bernard Metzler wrote:
> > To avoid racing with other user memory reservations, immediately
> > account full amount of pages to be pinned.
> >
> > Fixes: 2251334dcac9 ("rdma/siw: application buffer management")
> > Reported-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> > Suggested-by: Alistair Popple <apopple@xxxxxxxxxx>
> > Signed-off-by: Bernard Metzler <bmt@xxxxxxxxxxxxxx>
> > ---
> > drivers/infiniband/sw/siw/siw_mem.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/infiniband/sw/siw/siw_mem.c
> b/drivers/infiniband/sw/siw/siw_mem.c
> > index b2b33dd3b4fa..7cf4d927bbab 100644
> > --- a/drivers/infiniband/sw/siw/siw_mem.c
> > +++ b/drivers/infiniband/sw/siw/siw_mem.c
> > @@ -398,7 +398,8 @@ struct siw_umem *siw_umem_get(u64 start, u64 len,
> bool writable)
> >
> > mlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
> >
> > - if (num_pages + atomic64_read(&mm_s->pinned_vm) > mlock_limit) {
> > + if (num_pages + atomic64_add_return(num_pages, &mm_s->pinned_vm) >
> > + mlock_limit) {
>
> ???
>
> Doesn't atomic_add_return return the result of adding num_pages and
> pinned_vm? Then you add it again?
>
Stupid me. Thanks. Let me re-send
> Jason
