| From 82fa0a214489e3c8817db5d118d187eb06fd6a9c Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 4 May 2020 09:09:17 -0400 |
| Subject: IB/hfi1: Fix another case where pq is left on waitlist |
| |
| From: Mike Marciniszyn <mike.marciniszyn@intel.com> |
| |
| [ Upstream commit fa8dac3968635dec8518a13ac78d662f2aa88e4d ] |
| |
| The commit noted below fixed a case where a pq is left on the sdma wait |
| list. |
| |
| It however missed another case. |
| |
| user_sdma_send_pkts() has two calls from hfi1_user_sdma_process_request(). |
| |
| If the first one fails as indicated by -EBUSY, the pq will be placed on |
| the waitlist as by design. |
| |
| If the second call then succeeds, the pq is still on the waitlist setting |
| up a race with the interrupt handler if a subsequent request uses a |
| different SDMA engine |
| |
| Fix by deleting the first call. |
| |
| The use of pcount and the intent to send a short burst of packets followed |
| by the larger balance of packets was never correctly implemented, because |
| the two calls always send pcount packets no matter what. A subsequent |
| patch will correct that issue. |
| |
| Fixes: 9a293d1e21a6 ("IB/hfi1: Ensure pq is not left on waitlist") |
| Link: https://lore.kernel.org/r/20200504130917.175613.43231.stgit@awfm-01.aw.intel.com |
| Cc: <stable@vger.kernel.org> |
| Reviewed-by: Kaike Wan <kaike.wan@intel.com> |
| Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com> |
| Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/infiniband/hw/hfi1/user_sdma.c | 4 ---- |
| 1 file changed, 4 deletions(-) |
| |
| diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c |
| index 13e4203497b33..a92346e88628b 100644 |
| --- a/drivers/infiniband/hw/hfi1/user_sdma.c |
| +++ b/drivers/infiniband/hw/hfi1/user_sdma.c |
| @@ -589,10 +589,6 @@ int hfi1_user_sdma_process_request(struct hfi1_filedata *fd, |
| |
| set_comp_state(pq, cq, info.comp_idx, QUEUED, 0); |
| pq->state = SDMA_PKT_Q_ACTIVE; |
| - /* Send the first N packets in the request to buy us some time */ |
| - ret = user_sdma_send_pkts(req, pcount); |
| - if (unlikely(ret < 0 && ret != -EBUSY)) |
| - goto free_req; |
| |
| /* |
| * This is a somewhat blocking send implementation. |
| -- |
| 2.20.1 |
| |
