Re: [PATCH v2] IB/umem: ib_ucontext already have tgid, remove pid from ib_umem structure

[Jason Gunthorpe <jgg@ziepe.ca>]

On Tue, May 08, 2018 at 04:50:16PM +0800, Lidong Chen wrote:
> The userspace may invoke ibv_reg_mr and ibv_dereg_mr by different threads.
> If when ibv_dereg_mr invoke and the thread which invoked ibv_reg_mr has
> exited, get_pid_task will return NULL, ib_umem_release does not decrease
> mm->pinned_vm. This patch fixes it by use tgid in ib_ucontext struct.
> 
> Signed-off-by: Lidong Chen <lidongchen@tencent.com>
> ---
>  [v2]
>  - use ib_ucontext tgid instread of tgid in ib_umem structure
>  
>  drivers/infiniband/core/umem.c | 7 +------
>  include/rdma/ib_umem.h         | 1 -
>  2 files changed, 1 insertion(+), 7 deletions(-)

Applied to for-rc, thanks.

It would be nice to send a cleanup to have all the users of tgid doing
this pattern

	task = get_pid_task(umem->context->tgid, PIDTYPE_PID);
  	if (!task)
  		goto out;
  	mm = get_task_mm(task);

To call some kind of common function like ib_get_mr_mm(), just to make
it really clear what is happening. 

Jason