From 7b3256e331270c7de43ccf3879b7c289cdc3ff28 Mon Sep 17 00:00:00 2001 From: Dean Luick Date: Thu, 28 Jul 2016 15:21:18 -0400 Subject: [PATCH] IB/hfi1: Fix user SDMA racy user request claim The user SDMA in-use claim bit is in the structure that gets zeroed out once the claim is made. Move the request in-use flag into its own bit array and use that for atomic claims. This cleans up the claim code and removes any race possibility. Reviewed-by: Ira Weiny Signed-off-by: Dean Luick Signed-off-by: Doug Ledford --- drivers/infiniband/hw/hfi1/user_sdma.c | 32 +++++++++++++++----------- drivers/infiniband/hw/hfi1/user_sdma.h | 1 + 2 files changed, 20 insertions(+), 13 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c index 5c1322428065..e88d555389f4 100644 --- a/drivers/infiniband/hw/hfi1/user_sdma.c +++ b/drivers/infiniband/hw/hfi1/user_sdma.c @@ -145,7 +145,7 @@ MODULE_PARM_DESC(sdma_comp_size, "Size of User SDMA completion ring. Default: 12 /* Last packet in the request */ #define TXREQ_FLAGS_REQ_LAST_PKT BIT(0) -#define SDMA_REQ_IN_USE 0 +/* SDMA request flag bits */ #define SDMA_REQ_FOR_THREAD 1 #define SDMA_REQ_SEND_DONE 2 #define SDMA_REQ_HAVE_AHG 3 @@ -397,6 +397,11 @@ int hfi1_user_sdma_alloc_queues(struct hfi1_ctxtdata *uctxt, struct file *fp) if (!pq->reqs) goto pq_reqs_nomem; + memsize = BITS_TO_LONGS(hfi1_sdma_comp_ring_size) * sizeof(long); + pq->req_in_use = kzalloc(memsize, GFP_KERNEL); + if (!pq->req_in_use) + goto pq_reqs_no_in_use; + INIT_LIST_HEAD(&pq->list); pq->dd = dd; pq->ctxt = uctxt->ctxt; @@ -453,6 +458,8 @@ cq_comps_nomem: cq_nomem: kmem_cache_destroy(pq->txreq_cache); pq_txreq_nomem: + kfree(pq->req_in_use); +pq_reqs_no_in_use: kfree(pq->reqs); pq_reqs_nomem: kfree(pq); @@ -484,6 +491,7 @@ int hfi1_user_sdma_free_queues(struct hfi1_filedata *fd) pq->wait, (ACCESS_ONCE(pq->state) == SDMA_PKT_Q_INACTIVE)); kfree(pq->reqs); + kfree(pq->req_in_use); kmem_cache_destroy(pq->txreq_cache); kfree(pq); fd->pq = NULL; @@ -572,29 +580,27 @@ int hfi1_user_sdma_process_request(struct file *fp, struct iovec *iovec, return -EINVAL; } - if (cq->comps[info.comp_idx].status == QUEUED || - test_bit(SDMA_REQ_IN_USE, &pq->reqs[info.comp_idx].flags)) { - hfi1_cdbg(SDMA, "[%u:%u:%u] Entry %u is in QUEUED state", - dd->unit, uctxt->ctxt, fd->subctxt, - info.comp_idx); - return -EBADSLT; - } if (!info.fragsize) { hfi1_cdbg(SDMA, "[%u:%u:%u:%u] Request does not specify fragsize", dd->unit, uctxt->ctxt, fd->subctxt, info.comp_idx); return -EINVAL; } + + /* Try to claim the request. */ + if (test_and_set_bit(info.comp_idx, pq->req_in_use)) { + hfi1_cdbg(SDMA, "[%u:%u:%u] Entry %u is in use", + dd->unit, uctxt->ctxt, fd->subctxt, + info.comp_idx); + return -EBADSLT; + } /* - * We've done all the safety checks that we can up to this point, - * "allocate" the request entry. + * All safety checks have been done and this request has been claimed. */ hfi1_cdbg(SDMA, "[%u:%u:%u] Using req/comp entry %u\n", dd->unit, uctxt->ctxt, fd->subctxt, info.comp_idx); req = pq->reqs + info.comp_idx; memset(req, 0, sizeof(*req)); - /* Mark the request as IN_USE before we start filling it in. */ - set_bit(SDMA_REQ_IN_USE, &req->flags); req->data_iovs = req_iovcnt(info.ctrl) - 1; /* subtract header vector */ req->pq = pq; req->cq = cq; @@ -1612,7 +1618,7 @@ static void user_sdma_free_request(struct user_sdma_request *req, bool unpin) } } kfree(req->tids); - clear_bit(SDMA_REQ_IN_USE, &req->flags); + clear_bit(req->info.comp_idx, req->pq->req_in_use); } static inline void set_comp_state(struct hfi1_user_sdma_pkt_q *pq, diff --git a/drivers/infiniband/hw/hfi1/user_sdma.h b/drivers/infiniband/hw/hfi1/user_sdma.h index b9240e351161..20ff846f318b 100644 --- a/drivers/infiniband/hw/hfi1/user_sdma.h +++ b/drivers/infiniband/hw/hfi1/user_sdma.h @@ -63,6 +63,7 @@ struct hfi1_user_sdma_pkt_q { struct hfi1_devdata *dd; struct kmem_cache *txreq_cache; struct user_sdma_request *reqs; + unsigned long *req_in_use; struct iowait busy; unsigned state; wait_queue_head_t wait; -- 2.20.1