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... 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.