Messages in this thread | | | Subject | Re: [PATCH v5 5/9] IB/isert: Replace semaphore sem with completion | From | Sagi Grimberg <> | Date | Mon, 21 Nov 2016 14:33:02 +0200 |
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>>> diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c >>> index 6dd43f6..de80f56 100644 >>> --- a/drivers/infiniband/ulp/isert/ib_isert.c >>> +++ b/drivers/infiniband/ulp/isert/ib_isert.c >>> @@ -619,7 +619,7 @@ >>> mutex_unlock(&isert_np->mutex); >>> >>> isert_info("np %p: Allow accept_np to continue\n", isert_np); >>> - up(&isert_np->sem); >>> + complete(&isert_np->comp); >>> } >>> >>> static void >>> @@ -2311,7 +2311,7 @@ struct rdma_cm_id * >>> isert_err("Unable to allocate struct isert_np\n"); >>> return -ENOMEM; >>> } >>> - sema_init(&isert_np->sem, 0); >>> + init_completion(&isert_np->comp); >> >> This is still racy, a connect event can complete just before we >> init the completion and *will* get lost... >> >> This code started off with a waitqueue which exposes the same >> problem, see: >> 531b7bf4bd79 Target/iser: Fix iscsit_accept_np and rdma_cm racy flow >> >> So, still NAK from me... > > I don't see what you mean here. The code using a waitqueue had no > counter but the completion does.
The problem here is that init_completion sets the counter to zero and between this thread wakes up and until it initializes comp->done we might have another connect event completing it and I fail to see how this is handled correctly.
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