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drivers: Remove explicit invocations of mmiowb()
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mmiowb() is now implied by spin_unlock() on architectures that require
it, so there is no reason to call it from driver code. This patch was
generated using coccinelle:

	@mmiowb@
	@@
	- mmiowb();

and invoked as:

$ for d in drivers include/linux/qed sound; do \
spatch --include-headers --sp-file mmiowb.cocci --dir $d --in-place; done

NOTE: mmiowb() has only ever guaranteed ordering in conjunction with
spin_unlock(). However, pairing each mmiowb() removal in this patch with
the corresponding call to spin_unlock() is not at all trivial, so there
is a small chance that this change may regress any drivers incorrectly
relying on mmiowb() to order MMIO writes between CPUs using lock-free
synchronisation. If you've ended up bisecting to this commit, you can
reintroduce the mmiowb() calls using wmb() instead, which should restore
the old behaviour on all architectures other than some esoteric ia64
systems.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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@wildea01
wildea01 committed Apr 8, 2019
1 parent 949b8c7 commit fb24ea5
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Showing 123 changed files with 1 addition and 508 deletions.
4 changes: 0 additions & 4 deletions drivers/crypto/cavium/nitrox/nitrox_reqmgr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -303,8 +303,6 @@ static void post_se_instr(struct nitrox_softreq *sr,

/* Ring doorbell with count 1 */
writeq(1, cmdq->dbell_csr_addr);
/* orders the doorbell rings */
mmiowb();

cmdq->write_idx = incr_index(idx, 1, ndev->qlen);

Expand Down Expand Up @@ -599,8 +597,6 @@ void pkt_slc_resp_tasklet(unsigned long data)
* MSI-X interrupt generates if Completion count > Threshold
*/
writeq(slc_cnts.value, cmdq->compl_cnt_csr_addr);
/* order the writes */
mmiowb();

if (atomic_read(&cmdq->backlog_count))
schedule_work(&cmdq->backlog_qflush);
Expand Down
3 changes: 0 additions & 3 deletions drivers/dma/txx9dmac.c
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Original file line number Diff line number Diff line change
Expand Up @@ -327,7 +327,6 @@ static void txx9dmac_reset_chan(struct txx9dmac_chan *dc)
channel_writel(dc, SAIR, 0);
channel_writel(dc, DAIR, 0);
channel_writel(dc, CCR, 0);
mmiowb();
}

/* Called with dc->lock held and bh disabled */
Expand Down Expand Up @@ -954,7 +953,6 @@ static void txx9dmac_chain_dynamic(struct txx9dmac_chan *dc,
dma_sync_single_for_device(chan2parent(&dc->chan),
prev->txd.phys, ddev->descsize,
DMA_TO_DEVICE);
mmiowb();
if (!(channel_readl(dc, CSR) & TXX9_DMA_CSR_CHNEN) &&
channel_read_CHAR(dc) == prev->txd.phys)
/* Restart chain DMA */
Expand Down Expand Up @@ -1080,7 +1078,6 @@ static void txx9dmac_free_chan_resources(struct dma_chan *chan)
static void txx9dmac_off(struct txx9dmac_dev *ddev)
{
dma_writel(ddev, MCR, 0);
mmiowb();
}

static int __init txx9dmac_chan_probe(struct platform_device *pdev)
Expand Down
1 change: 0 additions & 1 deletion drivers/firewire/ohci.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2939,7 +2939,6 @@ static void set_multichannel_mask(struct fw_ohci *ohci, u64 channels)
reg_write(ohci, OHCI1394_IRMultiChanMaskLoClear, ~lo);
reg_write(ohci, OHCI1394_IRMultiChanMaskHiSet, hi);
reg_write(ohci, OHCI1394_IRMultiChanMaskLoSet, lo);
mmiowb();
ohci->mc_channels = channels;
}

Expand Down
10 changes: 0 additions & 10 deletions drivers/gpu/drm/i915/intel_hdmi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -182,15 +182,13 @@ static void g4x_write_infoframe(struct intel_encoder *encoder,

I915_WRITE(VIDEO_DIP_CTL, val);

mmiowb();
for (i = 0; i < len; i += 4) {
I915_WRITE(VIDEO_DIP_DATA, *data);
data++;
}
/* Write every possible data byte to force correct ECC calculation. */
for (; i < VIDEO_DIP_DATA_SIZE; i += 4)
I915_WRITE(VIDEO_DIP_DATA, 0);
mmiowb();

val |= g4x_infoframe_enable(type);
val &= ~VIDEO_DIP_FREQ_MASK;
Expand Down Expand Up @@ -237,15 +235,13 @@ static void ibx_write_infoframe(struct intel_encoder *encoder,

I915_WRITE(reg, val);

mmiowb();
for (i = 0; i < len; i += 4) {
I915_WRITE(TVIDEO_DIP_DATA(intel_crtc->pipe), *data);
data++;
}
/* Write every possible data byte to force correct ECC calculation. */
for (; i < VIDEO_DIP_DATA_SIZE; i += 4)
I915_WRITE(TVIDEO_DIP_DATA(intel_crtc->pipe), 0);
mmiowb();

val |= g4x_infoframe_enable(type);
val &= ~VIDEO_DIP_FREQ_MASK;
Expand Down Expand Up @@ -298,15 +294,13 @@ static void cpt_write_infoframe(struct intel_encoder *encoder,

I915_WRITE(reg, val);

mmiowb();
for (i = 0; i < len; i += 4) {
I915_WRITE(TVIDEO_DIP_DATA(intel_crtc->pipe), *data);
data++;
}
/* Write every possible data byte to force correct ECC calculation. */
for (; i < VIDEO_DIP_DATA_SIZE; i += 4)
I915_WRITE(TVIDEO_DIP_DATA(intel_crtc->pipe), 0);
mmiowb();

val |= g4x_infoframe_enable(type);
val &= ~VIDEO_DIP_FREQ_MASK;
Expand Down Expand Up @@ -352,15 +346,13 @@ static void vlv_write_infoframe(struct intel_encoder *encoder,

I915_WRITE(reg, val);

mmiowb();
for (i = 0; i < len; i += 4) {
I915_WRITE(VLV_TVIDEO_DIP_DATA(intel_crtc->pipe), *data);
data++;
}
/* Write every possible data byte to force correct ECC calculation. */
for (; i < VIDEO_DIP_DATA_SIZE; i += 4)
I915_WRITE(VLV_TVIDEO_DIP_DATA(intel_crtc->pipe), 0);
mmiowb();

val |= g4x_infoframe_enable(type);
val &= ~VIDEO_DIP_FREQ_MASK;
Expand Down Expand Up @@ -406,7 +398,6 @@ static void hsw_write_infoframe(struct intel_encoder *encoder,
val &= ~hsw_infoframe_enable(type);
I915_WRITE(ctl_reg, val);

mmiowb();
for (i = 0; i < len; i += 4) {
I915_WRITE(hsw_dip_data_reg(dev_priv, cpu_transcoder,
type, i >> 2), *data);
Expand All @@ -416,7 +407,6 @@ static void hsw_write_infoframe(struct intel_encoder *encoder,
for (; i < data_size; i += 4)
I915_WRITE(hsw_dip_data_reg(dev_priv, cpu_transcoder,
type, i >> 2), 0);
mmiowb();

val |= hsw_infoframe_enable(type);
I915_WRITE(ctl_reg, val);
Expand Down
2 changes: 0 additions & 2 deletions drivers/ide/tx4939ide.c
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Original file line number Diff line number Diff line change
Expand Up @@ -156,7 +156,6 @@ static u16 tx4939ide_check_error_ints(ide_hwif_t *hwif)
u16 sysctl = tx4939ide_readw(base, TX4939IDE_Sys_Ctl);

tx4939ide_writew(sysctl | 0x4000, base, TX4939IDE_Sys_Ctl);
mmiowb();
/* wait 12GBUSCLK (typ. 60ns @ GBUS200MHz, max 270ns) */
ndelay(270);
tx4939ide_writew(sysctl, base, TX4939IDE_Sys_Ctl);
Expand Down Expand Up @@ -396,7 +395,6 @@ static void tx4939ide_init_hwif(ide_hwif_t *hwif)

/* Soft Reset */
tx4939ide_writew(0x8000, base, TX4939IDE_Sys_Ctl);
mmiowb();
/* at least 20 GBUSCLK (typ. 100ns @ GBUS200MHz, max 450ns) */
ndelay(450);
tx4939ide_writew(0x0000, base, TX4939IDE_Sys_Ctl);
Expand Down
3 changes: 0 additions & 3 deletions drivers/infiniband/hw/hfi1/chip.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8365,7 +8365,6 @@ static inline void clear_recv_intr(struct hfi1_ctxtdata *rcd)
struct hfi1_devdata *dd = rcd->dd;
u32 addr = CCE_INT_CLEAR + (8 * rcd->ireg);

mmiowb();
write_csr(dd, addr, rcd->imask);
/* force the above write on the chip and get a value back */
(void)read_csr(dd, addr);
Expand Down Expand Up @@ -11803,12 +11802,10 @@ void update_usrhead(struct hfi1_ctxtdata *rcd, u32 hd, u32 updegr, u32 egrhd,
<< RCV_EGR_INDEX_HEAD_HEAD_SHIFT;
write_uctxt_csr(dd, ctxt, RCV_EGR_INDEX_HEAD, reg);
}
mmiowb();
reg = ((u64)rcv_intr_count << RCV_HDR_HEAD_COUNTER_SHIFT) |
(((u64)hd & RCV_HDR_HEAD_HEAD_MASK)
<< RCV_HDR_HEAD_HEAD_SHIFT);
write_uctxt_csr(dd, ctxt, RCV_HDR_HEAD, reg);
mmiowb();
}

u32 hdrqempty(struct hfi1_ctxtdata *rcd)
Expand Down
1 change: 0 additions & 1 deletion drivers/infiniband/hw/hfi1/pio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1578,7 +1578,6 @@ void hfi1_sc_wantpiobuf_intr(struct send_context *sc, u32 needint)
sc_del_credit_return_intr(sc);
trace_hfi1_wantpiointr(sc, needint, sc->credit_ctrl);
if (needint) {
mmiowb();
sc_return_credits(sc);
}
}
Expand Down
2 changes: 0 additions & 2 deletions drivers/infiniband/hw/hns/hns_roce_hw_v1.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1750,8 +1750,6 @@ static int hns_roce_v1_post_mbox(struct hns_roce_dev *hr_dev, u64 in_param,

writel(val, hcr + 5);

mmiowb();

return 0;
}

Expand Down
6 changes: 0 additions & 6 deletions drivers/infiniband/hw/mlx4/qp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3744,12 +3744,6 @@ static int _mlx4_ib_post_send(struct ib_qp *ibqp, const struct ib_send_wr *wr,
writel_relaxed(qp->doorbell_qpn,
to_mdev(ibqp->device)->uar_map + MLX4_SEND_DOORBELL);

/*
* Make sure doorbells don't leak out of SQ spinlock
* and reach the HCA out of order.
*/
mmiowb();

stamp_send_wqe(qp, ind + qp->sq_spare_wqes - 1);

qp->sq_next_wqe = ind;
Expand Down
1 change: 0 additions & 1 deletion drivers/infiniband/hw/mlx5/qp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5123,7 +5123,6 @@ static int _mlx5_ib_post_send(struct ib_qp *ibqp, const struct ib_send_wr *wr,
/* Make sure doorbells don't leak out of SQ spinlock
* and reach the HCA out of order.
*/
mmiowb();
bf->offset ^= bf->buf_size;
}

Expand Down
6 changes: 0 additions & 6 deletions drivers/infiniband/hw/mthca/mthca_cmd.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -292,12 +292,6 @@ static int mthca_cmd_post(struct mthca_dev *dev,
err = mthca_cmd_post_hcr(dev, in_param, out_param, in_modifier,
op_modifier, op, token, event);

/*
* Make sure that our HCR writes don't get mixed in with
* writes from another CPU starting a FW command.
*/
mmiowb();

mutex_unlock(&dev->cmd.hcr_mutex);
return err;
}
Expand Down
5 changes: 0 additions & 5 deletions drivers/infiniband/hw/mthca/mthca_cq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -211,11 +211,6 @@ static inline void update_cons_index(struct mthca_dev *dev, struct mthca_cq *cq,
mthca_write64(MTHCA_TAVOR_CQ_DB_INC_CI | cq->cqn, incr - 1,
dev->kar + MTHCA_CQ_DOORBELL,
MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
/*
* Make sure doorbells don't leak out of CQ spinlock
* and reach the HCA out of order:
*/
mmiowb();
}
}

Expand Down
17 changes: 0 additions & 17 deletions drivers/infiniband/hw/mthca/mthca_qp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1809,11 +1809,6 @@ int mthca_tavor_post_send(struct ib_qp *ibqp, const struct ib_send_wr *wr,
(qp->qpn << 8) | size0,
dev->kar + MTHCA_SEND_DOORBELL,
MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
/*
* Make sure doorbells don't leak out of SQ spinlock
* and reach the HCA out of order:
*/
mmiowb();
}

qp->sq.next_ind = ind;
Expand Down Expand Up @@ -1924,12 +1919,6 @@ int mthca_tavor_post_receive(struct ib_qp *ibqp, const struct ib_recv_wr *wr,
qp->rq.next_ind = ind;
qp->rq.head += nreq;

/*
* Make sure doorbells don't leak out of RQ spinlock and reach
* the HCA out of order:
*/
mmiowb();

spin_unlock_irqrestore(&qp->rq.lock, flags);
return err;
}
Expand Down Expand Up @@ -2164,12 +2153,6 @@ int mthca_arbel_post_send(struct ib_qp *ibqp, const struct ib_send_wr *wr,
MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
}

/*
* Make sure doorbells don't leak out of SQ spinlock and reach
* the HCA out of order:
*/
mmiowb();

spin_unlock_irqrestore(&qp->sq.lock, flags);
return err;
}
Expand Down
6 changes: 0 additions & 6 deletions drivers/infiniband/hw/mthca/mthca_srq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -570,12 +570,6 @@ int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, const struct ib_recv_wr *wr,
MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
}

/*
* Make sure doorbells don't leak out of SRQ spinlock and
* reach the HCA out of order:
*/
mmiowb();

spin_unlock_irqrestore(&srq->lock, flags);
return err;
}
Expand Down
12 changes: 0 additions & 12 deletions drivers/infiniband/hw/qedr/verbs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -773,9 +773,6 @@ static void doorbell_cq(struct qedr_cq *cq, u32 cons, u8 flags)
cq->db.data.agg_flags = flags;
cq->db.data.value = cpu_to_le32(cons);
writeq(cq->db.raw, cq->db_addr);

/* Make sure write would stick */
mmiowb();
}

int qedr_arm_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags flags)
Expand Down Expand Up @@ -2084,8 +2081,6 @@ static int qedr_update_qp_state(struct qedr_dev *dev,

if (rdma_protocol_roce(&dev->ibdev, 1)) {
writel(qp->rq.db_data.raw, qp->rq.db);
/* Make sure write takes effect */
mmiowb();
}
break;
case QED_ROCE_QP_STATE_ERR:
Expand Down Expand Up @@ -3502,9 +3497,6 @@ int qedr_post_send(struct ib_qp *ibqp, const struct ib_send_wr *wr,
smp_wmb();
writel(qp->sq.db_data.raw, qp->sq.db);

/* Make sure write sticks */
mmiowb();

spin_unlock_irqrestore(&qp->q_lock, flags);

return rc;
Expand Down Expand Up @@ -3695,12 +3687,8 @@ int qedr_post_recv(struct ib_qp *ibqp, const struct ib_recv_wr *wr,

writel(qp->rq.db_data.raw, qp->rq.db);

/* Make sure write sticks */
mmiowb();

if (rdma_protocol_iwarp(&dev->ibdev, 1)) {
writel(qp->rq.iwarp_db2_data.raw, qp->rq.iwarp_db2);
mmiowb();
}

wr = wr->next;
Expand Down
4 changes: 0 additions & 4 deletions drivers/infiniband/hw/qib/qib_iba6120.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1884,7 +1884,6 @@ static void qib_6120_put_tid(struct qib_devdata *dd, u64 __iomem *tidptr,
qib_write_kreg(dd, kr_scratch, 0xfeeddeaf);
writel(pa, tidp32);
qib_write_kreg(dd, kr_scratch, 0xdeadbeef);
mmiowb();
spin_unlock_irqrestore(tidlockp, flags);
}

Expand Down Expand Up @@ -1928,7 +1927,6 @@ static void qib_6120_put_tid_2(struct qib_devdata *dd, u64 __iomem *tidptr,
pa |= 2 << 29;
}
writel(pa, tidp32);
mmiowb();
}


Expand Down Expand Up @@ -2053,9 +2051,7 @@ static void qib_update_6120_usrhead(struct qib_ctxtdata *rcd, u64 hd,
{
if (updegr)
qib_write_ureg(rcd->dd, ur_rcvegrindexhead, egrhd, rcd->ctxt);
mmiowb();
qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
mmiowb();
}

static u32 qib_6120_hdrqempty(struct qib_ctxtdata *rcd)
Expand Down
3 changes: 0 additions & 3 deletions drivers/infiniband/hw/qib/qib_iba7220.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2175,7 +2175,6 @@ static void qib_7220_put_tid(struct qib_devdata *dd, u64 __iomem *tidptr,
pa = chippa;
}
writeq(pa, tidptr);
mmiowb();
}

/**
Expand Down Expand Up @@ -2704,9 +2703,7 @@ static void qib_update_7220_usrhead(struct qib_ctxtdata *rcd, u64 hd,
{
if (updegr)
qib_write_ureg(rcd->dd, ur_rcvegrindexhead, egrhd, rcd->ctxt);
mmiowb();
qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
mmiowb();
}

static u32 qib_7220_hdrqempty(struct qib_ctxtdata *rcd)
Expand Down
3 changes: 0 additions & 3 deletions drivers/infiniband/hw/qib/qib_iba7322.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3793,7 +3793,6 @@ static void qib_7322_put_tid(struct qib_devdata *dd, u64 __iomem *tidptr,
pa = chippa;
}
writeq(pa, tidptr);
mmiowb();
}

/**
Expand Down Expand Up @@ -4440,10 +4439,8 @@ static void qib_update_7322_usrhead(struct qib_ctxtdata *rcd, u64 hd,
adjust_rcv_timeout(rcd, npkts);
if (updegr)
qib_write_ureg(rcd->dd, ur_rcvegrindexhead, egrhd, rcd->ctxt);
mmiowb();
qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
mmiowb();
}

static u32 qib_7322_hdrqempty(struct qib_ctxtdata *rcd)
Expand Down
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