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?
Jason
