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authorDean Luick <dean.luick@intel.com>2016-07-28 15:21:18 -0400
committerDoug Ledford <dledford@redhat.com>2016-08-02 22:46:21 -0400
commit7b3256e331270c7de43ccf3879b7c289cdc3ff28 (patch)
treed25b92680b6edc3572e4bffd046049c685846c8f /drivers/infiniband
parent9da7e9a711e6fbecd111b9873682480c77c64192 (diff)
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 <ira.weiny@intel.com> Signed-off-by: Dean Luick <dean.luick@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/hw/hfi1/user_sdma.c32
-rw-r--r--drivers/infiniband/hw/hfi1/user_sdma.h1
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;