From cb7e125e03274cffa97d74433c876765efffaf6a Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 9 Oct 2017 09:26:25 -0700 Subject: drivers/net/ethernet/qlogic/qed: Fix __qed_spq_block() ordering The __qed_spq_block() function expects an smp_read_barrier_depends() to order a prior READ_ONCE() against a later load that does not depend on the prior READ_ONCE(), an expectation that can fail to be met. This commit therefore replaces the READ_ONCE() with smp_load_acquire() and removes the smp_read_barrier_depends(). Signed-off-by: Paul E. McKenney Cc: Ariel Elior Cc: Cc: --- drivers/net/ethernet/qlogic/qed/qed_spq.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'drivers') diff --git a/drivers/net/ethernet/qlogic/qed/qed_spq.c b/drivers/net/ethernet/qlogic/qed/qed_spq.c index be48d9abd001..c1237ec58b6c 100644 --- a/drivers/net/ethernet/qlogic/qed/qed_spq.c +++ b/drivers/net/ethernet/qlogic/qed/qed_spq.c @@ -97,9 +97,7 @@ static int __qed_spq_block(struct qed_hwfn *p_hwfn, while (iter_cnt--) { /* Validate we receive completion update */ - if (READ_ONCE(comp_done->done) == 1) { - /* Read updated FW return value */ - smp_read_barrier_depends(); + if (smp_load_acquire(&comp_done->done) == 1) { /* ^^^ */ if (p_fw_ret) *p_fw_ret = comp_done->fw_return_code; return 0; -- cgit v1.2.3 From adf90eb49055636fc35aede54174456ac3520f27 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 27 Nov 2017 09:04:22 -0800 Subject: drivers/infiniband: Remove now-redundant smp_read_barrier_depends() The smp_read_barrier_depends() does nothing at all except on DEC Alpha, and no current DEC Alpha systems use Infiniband: lkml.kernel.org/r/20171023085921.jwbntptn6ictbnvj@tower This commit therefore makes Infiniband depend on !ALPHA and removes the now-ineffective invocations of smp_read_barrier_depends() from the InfiniBand driver. Please note that this patch should not be construed as my saying that InfiniBand's memory ordering is correct, but rather that this patch does not in any way affect InfiniBand's correctness. In other words, the result of applying this patch is bug-for-bug compatible with the original. Signed-off-by: Paul E. McKenney Cc: Doug Ledford Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Michael Cree Cc: Andrea Parri Cc: Cc: [ paulmck: Removed drivers/dma/ioat/dma.c per Jason Gunthorpe's feedback. ] Acked-by: Jason Gunthorpe --- drivers/infiniband/Kconfig | 1 + drivers/infiniband/hw/hfi1/rc.c | 4 ---- drivers/infiniband/hw/hfi1/ruc.c | 1 - drivers/infiniband/hw/hfi1/sdma.c | 1 - drivers/infiniband/hw/hfi1/uc.c | 2 -- drivers/infiniband/hw/hfi1/ud.c | 2 -- drivers/infiniband/hw/qib/qib_rc.c | 3 --- drivers/infiniband/hw/qib/qib_ruc.c | 1 - drivers/infiniband/hw/qib/qib_uc.c | 2 -- drivers/infiniband/hw/qib/qib_ud.c | 2 -- drivers/infiniband/sw/rdmavt/qp.c | 1 - 11 files changed, 1 insertion(+), 19 deletions(-) (limited to 'drivers') diff --git a/drivers/infiniband/Kconfig b/drivers/infiniband/Kconfig index 98ac46ed7214..3bb6e35b0bbf 100644 --- a/drivers/infiniband/Kconfig +++ b/drivers/infiniband/Kconfig @@ -4,6 +4,7 @@ menuconfig INFINIBAND depends on NET depends on INET depends on m || IPV6 != m + depends on !ALPHA select IRQ_POLL ---help--- Core support for InfiniBand (IB). Make sure to also select diff --git a/drivers/infiniband/hw/hfi1/rc.c b/drivers/infiniband/hw/hfi1/rc.c index fd01a760259f..f527bcda4650 100644 --- a/drivers/infiniband/hw/hfi1/rc.c +++ b/drivers/infiniband/hw/hfi1/rc.c @@ -302,7 +302,6 @@ int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps) if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND)) goto bail; /* We are in the error state, flush the work request. */ - smp_read_barrier_depends(); /* see post_one_send() */ if (qp->s_last == READ_ONCE(qp->s_head)) goto bail; /* If DMAs are in progress, we can't flush immediately. */ @@ -346,7 +345,6 @@ int hfi1_make_rc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps) newreq = 0; if (qp->s_cur == qp->s_tail) { /* Check if send work queue is empty. */ - smp_read_barrier_depends(); /* see post_one_send() */ if (qp->s_tail == READ_ONCE(qp->s_head)) { clear_ahg(qp); goto bail; @@ -900,7 +898,6 @@ void hfi1_send_rc_ack(struct hfi1_ctxtdata *rcd, } /* Ensure s_rdma_ack_cnt changes are committed */ - smp_read_barrier_depends(); if (qp->s_rdma_ack_cnt) { hfi1_queue_rc_ack(qp, is_fecn); return; @@ -1562,7 +1559,6 @@ static void rc_rcv_resp(struct hfi1_packet *packet) trace_hfi1_ack(qp, psn); /* Ignore invalid responses. */ - smp_read_barrier_depends(); /* see post_one_send */ if (cmp_psn(psn, READ_ONCE(qp->s_next_psn)) >= 0) goto ack_done; diff --git a/drivers/infiniband/hw/hfi1/ruc.c b/drivers/infiniband/hw/hfi1/ruc.c index 2c7fc6e331ea..13b994738f41 100644 --- a/drivers/infiniband/hw/hfi1/ruc.c +++ b/drivers/infiniband/hw/hfi1/ruc.c @@ -362,7 +362,6 @@ static void ruc_loopback(struct rvt_qp *sqp) sqp->s_flags |= RVT_S_BUSY; again: - smp_read_barrier_depends(); /* see post_one_send() */ if (sqp->s_last == READ_ONCE(sqp->s_head)) goto clr_busy; wqe = rvt_get_swqe_ptr(sqp, sqp->s_last); diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c index 31c8f89b5fc8..61c130dbed10 100644 --- a/drivers/infiniband/hw/hfi1/sdma.c +++ b/drivers/infiniband/hw/hfi1/sdma.c @@ -553,7 +553,6 @@ static void sdma_hw_clean_up_task(unsigned long opaque) static inline struct sdma_txreq *get_txhead(struct sdma_engine *sde) { - smp_read_barrier_depends(); /* see sdma_update_tail() */ return sde->tx_ring[sde->tx_head & sde->sdma_mask]; } diff --git a/drivers/infiniband/hw/hfi1/uc.c b/drivers/infiniband/hw/hfi1/uc.c index 991bbee04821..132b63e787d1 100644 --- a/drivers/infiniband/hw/hfi1/uc.c +++ b/drivers/infiniband/hw/hfi1/uc.c @@ -79,7 +79,6 @@ int hfi1_make_uc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps) if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND)) goto bail; /* We are in the error state, flush the work request. */ - smp_read_barrier_depends(); /* see post_one_send() */ if (qp->s_last == READ_ONCE(qp->s_head)) goto bail; /* If DMAs are in progress, we can't flush immediately. */ @@ -119,7 +118,6 @@ int hfi1_make_uc_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps) RVT_PROCESS_NEXT_SEND_OK)) goto bail; /* Check if send work queue is empty. */ - smp_read_barrier_depends(); /* see post_one_send() */ if (qp->s_cur == READ_ONCE(qp->s_head)) { clear_ahg(qp); goto bail; diff --git a/drivers/infiniband/hw/hfi1/ud.c b/drivers/infiniband/hw/hfi1/ud.c index beb5091eccca..deb184574395 100644 --- a/drivers/infiniband/hw/hfi1/ud.c +++ b/drivers/infiniband/hw/hfi1/ud.c @@ -486,7 +486,6 @@ int hfi1_make_ud_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps) if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND)) goto bail; /* We are in the error state, flush the work request. */ - smp_read_barrier_depends(); /* see post_one_send */ if (qp->s_last == READ_ONCE(qp->s_head)) goto bail; /* If DMAs are in progress, we can't flush immediately. */ @@ -500,7 +499,6 @@ int hfi1_make_ud_req(struct rvt_qp *qp, struct hfi1_pkt_state *ps) } /* see post_one_send() */ - smp_read_barrier_depends(); if (qp->s_cur == READ_ONCE(qp->s_head)) goto bail; diff --git a/drivers/infiniband/hw/qib/qib_rc.c b/drivers/infiniband/hw/qib/qib_rc.c index 8f5754fb8579..1a785c37ad0a 100644 --- a/drivers/infiniband/hw/qib/qib_rc.c +++ b/drivers/infiniband/hw/qib/qib_rc.c @@ -246,7 +246,6 @@ int qib_make_rc_req(struct rvt_qp *qp, unsigned long *flags) if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND)) goto bail; /* We are in the error state, flush the work request. */ - smp_read_barrier_depends(); /* see post_one_send() */ if (qp->s_last == READ_ONCE(qp->s_head)) goto bail; /* If DMAs are in progress, we can't flush immediately. */ @@ -293,7 +292,6 @@ int qib_make_rc_req(struct rvt_qp *qp, unsigned long *flags) newreq = 0; if (qp->s_cur == qp->s_tail) { /* Check if send work queue is empty. */ - smp_read_barrier_depends(); /* see post_one_send() */ if (qp->s_tail == READ_ONCE(qp->s_head)) goto bail; /* @@ -1340,7 +1338,6 @@ static void qib_rc_rcv_resp(struct qib_ibport *ibp, goto ack_done; /* Ignore invalid responses. */ - smp_read_barrier_depends(); /* see post_one_send */ if (qib_cmp24(psn, READ_ONCE(qp->s_next_psn)) >= 0) goto ack_done; diff --git a/drivers/infiniband/hw/qib/qib_ruc.c b/drivers/infiniband/hw/qib/qib_ruc.c index 9a37e844d4c8..4662cc7bde92 100644 --- a/drivers/infiniband/hw/qib/qib_ruc.c +++ b/drivers/infiniband/hw/qib/qib_ruc.c @@ -367,7 +367,6 @@ static void qib_ruc_loopback(struct rvt_qp *sqp) sqp->s_flags |= RVT_S_BUSY; again: - smp_read_barrier_depends(); /* see post_one_send() */ if (sqp->s_last == READ_ONCE(sqp->s_head)) goto clr_busy; wqe = rvt_get_swqe_ptr(sqp, sqp->s_last); diff --git a/drivers/infiniband/hw/qib/qib_uc.c b/drivers/infiniband/hw/qib/qib_uc.c index bddcc37ace44..70c58b88192c 100644 --- a/drivers/infiniband/hw/qib/qib_uc.c +++ b/drivers/infiniband/hw/qib/qib_uc.c @@ -60,7 +60,6 @@ int qib_make_uc_req(struct rvt_qp *qp, unsigned long *flags) if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND)) goto bail; /* We are in the error state, flush the work request. */ - smp_read_barrier_depends(); /* see post_one_send() */ if (qp->s_last == READ_ONCE(qp->s_head)) goto bail; /* If DMAs are in progress, we can't flush immediately. */ @@ -90,7 +89,6 @@ int qib_make_uc_req(struct rvt_qp *qp, unsigned long *flags) RVT_PROCESS_NEXT_SEND_OK)) goto bail; /* Check if send work queue is empty. */ - smp_read_barrier_depends(); /* see post_one_send() */ if (qp->s_cur == READ_ONCE(qp->s_head)) goto bail; /* diff --git a/drivers/infiniband/hw/qib/qib_ud.c b/drivers/infiniband/hw/qib/qib_ud.c index 15962ed193ce..386c3c4da0c7 100644 --- a/drivers/infiniband/hw/qib/qib_ud.c +++ b/drivers/infiniband/hw/qib/qib_ud.c @@ -252,7 +252,6 @@ int qib_make_ud_req(struct rvt_qp *qp, unsigned long *flags) if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND)) goto bail; /* We are in the error state, flush the work request. */ - smp_read_barrier_depends(); /* see post_one_send */ if (qp->s_last == READ_ONCE(qp->s_head)) goto bail; /* If DMAs are in progress, we can't flush immediately. */ @@ -266,7 +265,6 @@ int qib_make_ud_req(struct rvt_qp *qp, unsigned long *flags) } /* see post_one_send() */ - smp_read_barrier_depends(); if (qp->s_cur == READ_ONCE(qp->s_head)) goto bail; diff --git a/drivers/infiniband/sw/rdmavt/qp.c b/drivers/infiniband/sw/rdmavt/qp.c index 9177df60742a..eae84c216e2f 100644 --- a/drivers/infiniband/sw/rdmavt/qp.c +++ b/drivers/infiniband/sw/rdmavt/qp.c @@ -1684,7 +1684,6 @@ static inline int rvt_qp_is_avail( /* non-reserved operations */ if (likely(qp->s_avail)) return 0; - smp_read_barrier_depends(); /* see rc.c */ slast = READ_ONCE(qp->s_last); if (qp->s_head >= slast) avail = qp->s_size - (qp->s_head - slast); -- cgit v1.2.3 From 98c1ec7cefaadbf65680d116c3d8612b93a841a0 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 1 Dec 2017 17:04:39 -0800 Subject: drivers/dma/ioat: Remove now-redundant smp_read_barrier_depends() Now that READ_ONCE() implies smp_read_barrier_depends(), the __cleanup() and ioat_abort_descs() functions no longer need their smp_read_barrier_depends() calls, which this commit removes. It is actually not entirely clear why this driver ever included smp_read_barrier_depends() given that it appears to be x86-only and given that smp_read_barrier_depends() has no effect whatsoever except on DEC Alpha. Signed-off-by: Paul E. McKenney Cc: Vinod Koul Cc: Dan Williams Cc: --- drivers/dma/ioat/dma.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'drivers') diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c index 58d4ccd33672..8b5b23a8ace9 100644 --- a/drivers/dma/ioat/dma.c +++ b/drivers/dma/ioat/dma.c @@ -597,7 +597,6 @@ static void __cleanup(struct ioatdma_chan *ioat_chan, dma_addr_t phys_complete) for (i = 0; i < active && !seen_current; i++) { struct dma_async_tx_descriptor *tx; - smp_read_barrier_depends(); prefetch(ioat_get_ring_ent(ioat_chan, idx + i + 1)); desc = ioat_get_ring_ent(ioat_chan, idx + i); dump_desc_dbg(ioat_chan, desc); @@ -715,7 +714,6 @@ static void ioat_abort_descs(struct ioatdma_chan *ioat_chan) for (i = 1; i < active; i++) { struct dma_async_tx_descriptor *tx; - smp_read_barrier_depends(); prefetch(ioat_get_ring_ent(ioat_chan, idx + i + 1)); desc = ioat_get_ring_ent(ioat_chan, idx + i); -- cgit v1.2.3 From 3a5db0b108e0a40f08c2bcff6a675dbf632b91e0 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 27 Nov 2017 09:45:10 -0800 Subject: drivers/vhost: Remove now-redundant read_barrier_depends() Because READ_ONCE() now implies read_barrier_depends(), the read_barrier_depends() in next_desc() is now redundant. This commit therefore removes it and the related comments. Signed-off-by: Paul E. McKenney Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Cc: Cc: --- drivers/vhost/vhost.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'drivers') diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 33ac2b186b85..78b5940a415a 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1877,12 +1877,7 @@ static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc) return -1U; /* Check they're not leading us off end of descriptors. */ - next = vhost16_to_cpu(vq, desc->next); - /* Make sure compiler knows to grab that: we don't want it changing! */ - /* We will use the result as an index in an array, so most - * architectures only need a compiler barrier here. */ - read_barrier_depends(); - + next = vhost16_to_cpu(vq, READ_ONCE(desc->next)); return next; } -- cgit v1.2.3