[PATCH 0/5] arcnet: Collection of latest fixes

[PATCH 0/5] arcnet: Collection of latest fixes

[Michael Grzeschik]

Here we sum up the recent fixes I collected on the way to use and
stabilise the framework. Part of it is an possible deadlock that we
prevent as well to fix the calculation of the dev_id that can be setup
by an rotary encoder. Beside that we added an trivial spelling patch and
fix some wrong and missing assignments that improves the code footprint.

Colin Ian King (1):
  Trivial fix to spelling mistake in arc_printk message

Michael Grzeschik (4):
  arcnet: change irq handler to lock irqsave
  arcnet: com20020: remove needless base_addr assignment
  arcnet: com20020-pci: fix dev_id calculation
  arcnet: com20020-pci: add missing pdev setup in netdev structure

 drivers/net/arcnet/arcnet.c       | 7 ++++---
 drivers/net/arcnet/capmode.c      | 2 +-
 drivers/net/arcnet/com20020-pci.c | 6 ++++--
 drivers/net/arcnet/com20020.c     | 2 --
 4 files changed, 9 insertions(+), 8 deletions(-)

-- 
2.11.0

[PATCH 1/5] arcnet: change irq handler to lock irqsave

[Michael Grzeschik]

This patch prevents the arcnet driver from the following deadlock.

[   41.273910] ======================================================
[   41.280397] [ INFO: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected ]
[   41.287433] 4.4.0-00034-gc0ae784 #536 Not tainted
[   41.292366] ------------------------------------------------------
[   41.298863] arcecho/233 [HC0[0]:SC0[2]:HE0:SE0] is trying to acquire:
[   41.305628]  (&(&lp->lock)->rlock){+.+...}, at: [<bf083bc8>] arcnet_send_packet+0x60/0x1c0 [arcnet]
[   41.315199]
[   41.315199] and this task is already holding:
[   41.321324]  (_xmit_ARCNET#2){+.-...}, at: [<c06b934c>] packet_direct_xmit+0xfc/0x1c8
[   41.329593] which would create a new lock dependency:
[   41.334893]  (_xmit_ARCNET#2){+.-...} -> (&(&lp->lock)->rlock){+.+...}
[   41.341801]
[   41.341801] but this new dependency connects a SOFTIRQ-irq-safe lock:
[   41.350108]  (_xmit_ARCNET#2){+.-...}
... which became SOFTIRQ-irq-safe at:
[   41.357539]   [<c06f8fc8>] _raw_spin_lock+0x30/0x40
[   41.362677]   [<c063ab8c>] dev_watchdog+0x5c/0x264
[   41.367723]   [<c0094edc>] call_timer_fn+0x6c/0xf4
[   41.372759]   [<c00950b8>] run_timer_softirq+0x154/0x210
[   41.378340]   [<c0036b30>] __do_softirq+0x144/0x298
[   41.383469]   [<c0036fb4>] irq_exit+0xcc/0x130
[   41.388138]   [<c0085c50>] __handle_domain_irq+0x60/0xb4
[   41.393728]   [<c0014578>] __irq_svc+0x58/0x78
[   41.398402]   [<c0010274>] arch_cpu_idle+0x24/0x3c
[   41.403443]   [<c007127c>] cpu_startup_entry+0x1f8/0x25c
[   41.409029]   [<c09adc90>] start_kernel+0x3c0/0x3cc
[   41.414170]
[   41.414170] to a SOFTIRQ-irq-unsafe lock:
[   41.419931]  (&(&lp->lock)->rlock){+.+...}
... which became SOFTIRQ-irq-unsafe at:
[   41.427996] ...  [<c06f8fc8>] _raw_spin_lock+0x30/0x40
[   41.433409]   [<bf083d54>] arcnet_interrupt+0x2c/0x800 [arcnet]
[   41.439646]   [<c0089120>] handle_nested_irq+0x8c/0xec
[   41.445063]   [<c03c1170>] regmap_irq_thread+0x190/0x314
[   41.450661]   [<c0087244>] irq_thread_fn+0x1c/0x34
[   41.455700]   [<c0087548>] irq_thread+0x13c/0x1dc
[   41.460649]   [<c0050f10>] kthread+0xe4/0xf8
[   41.465158]   [<c000f810>] ret_from_fork+0x14/0x24
[   41.470207]
[   41.470207] other info that might help us debug this:
[   41.470207]
[   41.478627]  Possible interrupt unsafe locking scenario:
[   41.478627]
[   41.485763]        CPU0                    CPU1
[   41.490521]        ----                    ----
[   41.495279]   lock(&(&lp->lock)->rlock);
[   41.499414]                                local_irq_disable();
[   41.505636]                                lock(_xmit_ARCNET#2);
[   41.511967]                                lock(&(&lp->lock)->rlock);
[   41.518741]   <Interrupt>
[   41.521490]     lock(_xmit_ARCNET#2);
[   41.525356]
[   41.525356]  *** DEADLOCK ***
[   41.525356]
[   41.531587] 1 lock held by arcecho/233:
[   41.535617]  #0:  (_xmit_ARCNET#2){+.-...}, at: [<c06b934c>] packet_direct_xmit+0xfc/0x1c8
[   41.544355]
the dependencies between SOFTIRQ-irq-safe lock and the holding lock:
[   41.552362] -> (_xmit_ARCNET#2){+.-...} ops: 27 {
[   41.557357]    HARDIRQ-ON-W at:
[   41.560664]                     [<c06f8fc8>] _raw_spin_lock+0x30/0x40
[   41.567445]                     [<c063ba28>] dev_deactivate_many+0x114/0x304
[   41.574866]                     [<c063bc3c>] dev_deactivate+0x24/0x38
[   41.581646]                     [<c0630374>] linkwatch_do_dev+0x40/0x74
[   41.588613]                     [<c06305d8>] __linkwatch_run_queue+0xec/0x140
[   41.596120]                     [<c0630658>] linkwatch_event+0x2c/0x34
[   41.602991]                     [<c004af30>] process_one_work+0x188/0x40c
[   41.610131]                     [<c004b200>] worker_thread+0x4c/0x480
[   41.616912]                     [<c0050f10>] kthread+0xe4/0xf8
[   41.623048]                     [<c000f810>] ret_from_fork+0x14/0x24
[   41.629735]    IN-SOFTIRQ-W at:
[   41.633039]                     [<c06f8fc8>] _raw_spin_lock+0x30/0x40
[   41.639820]                     [<c063ab8c>] dev_watchdog+0x5c/0x264
[   41.646508]                     [<c0094edc>] call_timer_fn+0x6c/0xf4
[   41.653190]                     [<c00950b8>] run_timer_softirq+0x154/0x210
[   41.660425]                     [<c0036b30>] __do_softirq+0x144/0x298
[   41.667201]                     [<c0036fb4>] irq_exit+0xcc/0x130
[   41.673518]                     [<c0085c50>] __handle_domain_irq+0x60/0xb4
[   41.680754]                     [<c0014578>] __irq_svc+0x58/0x78
[   41.687077]                     [<c0010274>] arch_cpu_idle+0x24/0x3c
[   41.693769]                     [<c007127c>] cpu_startup_entry+0x1f8/0x25c
[   41.701006]                     [<c09adc90>] start_kernel+0x3c0/0x3cc
[   41.707791]    INITIAL USE at:
[   41.711003]                    [<c06f8fc8>] _raw_spin_lock+0x30/0x40
[   41.717696]                    [<c063ba28>] dev_deactivate_many+0x114/0x304
[   41.725026]                    [<c063bc3c>] dev_deactivate+0x24/0x38
[   41.731718]                    [<c0630374>] linkwatch_do_dev+0x40/0x74
[   41.738593]                    [<c06305d8>] __linkwatch_run_queue+0xec/0x140
[   41.746011]                    [<c0630658>] linkwatch_event+0x2c/0x34
[   41.752789]                    [<c004af30>] process_one_work+0x188/0x40c
[   41.759847]                    [<c004b200>] worker_thread+0x4c/0x480
[   41.766541]                    [<c0050f10>] kthread+0xe4/0xf8
[   41.772596]                    [<c000f810>] ret_from_fork+0x14/0x24
[   41.779198]  }
[   41.780945]  ... key      at: [<c124d620>] netdev_xmit_lock_key+0x38/0x1c8
[   41.788192]  ... acquired at:
[   41.791309]    [<c007bed8>] lock_acquire+0x70/0x90
[   41.796361]    [<c06f9140>] _raw_spin_lock_irqsave+0x40/0x54
[   41.802324]    [<bf083bc8>] arcnet_send_packet+0x60/0x1c0 [arcnet]
[   41.808844]    [<c06b9380>] packet_direct_xmit+0x130/0x1c8
[   41.814622]    [<c06bc7e4>] packet_sendmsg+0x3b8/0x680
[   41.820034]    [<c05fe8b0>] sock_sendmsg+0x14/0x24
[   41.825091]    [<c05ffd68>] SyS_sendto+0xb8/0xe0
[   41.829956]    [<c05ffda8>] SyS_send+0x18/0x20
[   41.834638]    [<c000f780>] ret_fast_syscall+0x0/0x1c
[   41.839954]
[   41.841514]
the dependencies between the lock to be acquired and SOFTIRQ-irq-unsafe lock:
[   41.850302] -> (&(&lp->lock)->rlock){+.+...} ops: 5 {
[   41.855644]    HARDIRQ-ON-W at:
[   41.858945]                     [<c06f8fc8>] _raw_spin_lock+0x30/0x40
[   41.865726]                     [<bf083d54>] arcnet_interrupt+0x2c/0x800 [arcnet]
[   41.873607]                     [<c0089120>] handle_nested_irq+0x8c/0xec
[   41.880666]                     [<c03c1170>] regmap_irq_thread+0x190/0x314
[   41.887901]                     [<c0087244>] irq_thread_fn+0x1c/0x34
[   41.894593]                     [<c0087548>] irq_thread+0x13c/0x1dc
[   41.901195]                     [<c0050f10>] kthread+0xe4/0xf8
[   41.907338]                     [<c000f810>] ret_from_fork+0x14/0x24
[   41.914025]    SOFTIRQ-ON-W at:
[   41.917328]                     [<c06f8fc8>] _raw_spin_lock+0x30/0x40
[   41.924106]                     [<bf083d54>] arcnet_interrupt+0x2c/0x800 [arcnet]
[   41.931981]                     [<c0089120>] handle_nested_irq+0x8c/0xec
[   41.939028]                     [<c03c1170>] regmap_irq_thread+0x190/0x314
[   41.946264]                     [<c0087244>] irq_thread_fn+0x1c/0x34
[   41.952954]                     [<c0087548>] irq_thread+0x13c/0x1dc
[   41.959548]                     [<c0050f10>] kthread+0xe4/0xf8
[   41.965689]                     [<c000f810>] ret_from_fork+0x14/0x24
[   41.972379]    INITIAL USE at:
[   41.975595]                    [<c06f8fc8>] _raw_spin_lock+0x30/0x40
[   41.982283]                    [<bf083d54>] arcnet_interrupt+0x2c/0x800 [arcnet]
[   41.990063]                    [<c0089120>] handle_nested_irq+0x8c/0xec
[   41.997027]                    [<c03c1170>] regmap_irq_thread+0x190/0x314
[   42.004172]                    [<c0087244>] irq_thread_fn+0x1c/0x34
[   42.010766]                    [<c0087548>] irq_thread+0x13c/0x1dc
[   42.017267]                    [<c0050f10>] kthread+0xe4/0xf8
[   42.023314]                    [<c000f810>] ret_from_fork+0x14/0x24
[   42.029903]  }
[   42.031648]  ... key      at: [<bf0854cc>] __key.42091+0x0/0xfffff0f8 [arcnet]
[   42.039255]  ... acquired at:
[   42.042372]    [<c007bed8>] lock_acquire+0x70/0x90
[   42.047413]    [<c06f9140>] _raw_spin_lock_irqsave+0x40/0x54
[   42.053364]    [<bf083bc8>] arcnet_send_packet+0x60/0x1c0 [arcnet]
[   42.059872]    [<c06b9380>] packet_direct_xmit+0x130/0x1c8
[   42.065634]    [<c06bc7e4>] packet_sendmsg+0x3b8/0x680
[   42.071030]    [<c05fe8b0>] sock_sendmsg+0x14/0x24
[   42.076069]    [<c05ffd68>] SyS_sendto+0xb8/0xe0
[   42.080926]    [<c05ffda8>] SyS_send+0x18/0x20
[   42.085601]    [<c000f780>] ret_fast_syscall+0x0/0x1c
[   42.090918]
[   42.092481]
[   42.092481] stack backtrace:
[   42.097065] CPU: 0 PID: 233 Comm: arcecho Not tainted 4.4.0-00034-gc0ae784 #536
[   42.104751] Hardware name: Generic AM33XX (Flattened Device Tree)
[   42.111183] [<c0017ec8>] (unwind_backtrace) from [<c00139d0>] (show_stack+0x10/0x14)
[   42.119337] [<c00139d0>] (show_stack) from [<c02a82c4>] (dump_stack+0x8c/0x9c)
[   42.126937] [<c02a82c4>] (dump_stack) from [<c0078260>] (check_usage+0x4bc/0x63c)
[   42.134815] [<c0078260>] (check_usage) from [<c0078438>] (check_irq_usage+0x58/0xb0)
[   42.142964] [<c0078438>] (check_irq_usage) from [<c007aaa0>] (__lock_acquire+0x1524/0x20b0)
[   42.151740] [<c007aaa0>] (__lock_acquire) from [<c007bed8>] (lock_acquire+0x70/0x90)
[   42.159886] [<c007bed8>] (lock_acquire) from [<c06f9140>] (_raw_spin_lock_irqsave+0x40/0x54)
[   42.168768] [<c06f9140>] (_raw_spin_lock_irqsave) from [<bf083bc8>] (arcnet_send_packet+0x60/0x1c0 [arcnet])
[   42.179115] [<bf083bc8>] (arcnet_send_packet [arcnet]) from [<c06b9380>] (packet_direct_xmit+0x130/0x1c8)
[   42.189182] [<c06b9380>] (packet_direct_xmit) from [<c06bc7e4>] (packet_sendmsg+0x3b8/0x680)
[   42.198059] [<c06bc7e4>] (packet_sendmsg) from [<c05fe8b0>] (sock_sendmsg+0x14/0x24)
[   42.206199] [<c05fe8b0>] (sock_sendmsg) from [<c05ffd68>] (SyS_sendto+0xb8/0xe0)
[   42.213978] [<c05ffd68>] (SyS_sendto) from [<c05ffda8>] (SyS_send+0x18/0x20)
[   42.221388] [<c05ffda8>] (SyS_send) from [<c000f780>] (ret_fast_syscall+0x0/0x1c)

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>

   ---
   v1 -> v2: removed unneeded zero assignment of flags
---
 drivers/net/arcnet/arcnet.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/arcnet/arcnet.c b/drivers/net/arcnet/arcnet.c
index 62ee439d58829..53a1cb551defa 100644
--- a/drivers/net/arcnet/arcnet.c
+++ b/drivers/net/arcnet/arcnet.c
@@ -756,6 +756,7 @@ irqreturn_t arcnet_interrupt(int irq, void *dev_id)
 	struct net_device *dev = dev_id;
 	struct arcnet_local *lp;
 	int recbuf, status, diagstatus, didsomething, boguscount;
+	unsigned long flags;
 	int retval = IRQ_NONE;
 
 	arc_printk(D_DURING, dev, "\n");
@@ -765,7 +766,7 @@ irqreturn_t arcnet_interrupt(int irq, void *dev_id)
 	lp = netdev_priv(dev);
 	BUG_ON(!lp);
 
-	spin_lock(&lp->lock);
+	spin_lock_irqsave(&lp->lock, flags);
 
 	/* RESET flag was enabled - if device is not running, we must
 	 * clear it right away (but nothing else).
@@ -774,7 +775,7 @@ irqreturn_t arcnet_interrupt(int irq, void *dev_id)
 		if (lp->hw.status(dev) & RESETflag)
 			lp->hw.command(dev, CFLAGScmd | RESETclear);
 		lp->hw.intmask(dev, 0);
-		spin_unlock(&lp->lock);
+		spin_unlock_irqrestore(&lp->lock, flags);
 		return retval;
 	}
 
@@ -998,7 +999,7 @@ irqreturn_t arcnet_interrupt(int irq, void *dev_id)
 	udelay(1);
 	lp->hw.intmask(dev, lp->intmask);
 
-	spin_unlock(&lp->lock);
+	spin_unlock_irqrestore(&lp->lock, flags);
 	return retval;
 }
 EXPORT_SYMBOL(arcnet_interrupt);
-- 
2.11.0

[PATCH 2/5] Trivial fix to spelling mistake in arc_printk message

[Michael Grzeschik]

From: Colin Ian King <colin.king@canonical.com>

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
 drivers/net/arcnet/capmode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/arcnet/capmode.c b/drivers/net/arcnet/capmode.c
index a80f4eb9262d5..b780be6f41ff9 100644
--- a/drivers/net/arcnet/capmode.c
+++ b/drivers/net/arcnet/capmode.c
@@ -212,7 +212,7 @@ static int ack_tx(struct net_device *dev, int acked)
 	ackpkt->soft.cap.proto = 0; /* using protocol 0 for acknowledge */
 	ackpkt->soft.cap.mes.ack = acked;
 
-	arc_printk(D_PROTO, dev, "Ackknowledge for cap packet %x.\n",
+	arc_printk(D_PROTO, dev, "Acknowledge for cap packet %x.\n",
 		   *((int *)&ackpkt->soft.cap.cookie[0]));
 
 	ackskb->protocol = cpu_to_be16(ETH_P_ARCNET);
-- 
2.11.0

[PATCH 3/5] arcnet: com20020: remove needless base_addr assignment

[Michael Grzeschik]

The assignment is superfluous.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
 drivers/net/arcnet/com20020.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/net/arcnet/com20020.c b/drivers/net/arcnet/com20020.c
index 13d9ad4b3f5c9..78043a9c5981e 100644
--- a/drivers/net/arcnet/com20020.c
+++ b/drivers/net/arcnet/com20020.c
@@ -246,8 +246,6 @@ int com20020_found(struct net_device *dev, int shared)
 		return -ENODEV;
 	}
 
-	dev->base_addr = ioaddr;
-
 	arc_printk(D_NORMAL, dev, "%s: station %02Xh found at %03lXh, IRQ %d.\n",
 		   lp->card_name, dev->dev_addr[0], dev->base_addr, dev->irq);
 
-- 
2.11.0

[PATCH 4/5] arcnet: com20020-pci: fix dev_id calculation

[Michael Grzeschik]

The dev_id was miscalculated. Only the two bits 4-5 are relevant for the
MA1 card. PCIARC1 and PCIFB2 use the four bits 4-7 for id selection.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
 drivers/net/arcnet/com20020-pci.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/arcnet/com20020-pci.c b/drivers/net/arcnet/com20020-pci.c
index 239de38fbd6a5..fec2df2c869fe 100644
--- a/drivers/net/arcnet/com20020-pci.c
+++ b/drivers/net/arcnet/com20020-pci.c
@@ -135,6 +135,7 @@ static int com20020pci_probe(struct pci_dev *pdev,
 	for (i = 0; i < ci->devcount; i++) {
 		struct com20020_pci_channel_map *cm = &ci->chan_map_tbl[i];
 		struct com20020_dev *card;
+		int dev_id_mask = 0xf;
 
 		dev = alloc_arcdev(device);
 		if (!dev) {
@@ -179,8 +180,8 @@ static int com20020pci_probe(struct pci_dev *pdev,
 
 		/* Get the dev_id from the PLX rotary coder */
 		if (!strncmp(ci->name, "EAE PLX-PCI MA1", 15))
-			dev->dev_id = 0xc;
-		dev->dev_id ^= inb(priv->misc + ci->rotary) >> 4;
+			dev_id_mask = 0x3;
+		dev->dev_id = (inb(priv->misc + ci->rotary) >> 4) & dev_id_mask;
 
 		snprintf(dev->name, sizeof(dev->name), "arc%d-%d", dev->dev_id, i);
 
-- 
2.11.0

[PATCH 5/5] arcnet: com20020-pci: add missing pdev setup in netdev structure

[Michael Grzeschik]

We add the pdev data to the pci devices netdev structure. This way
the interface get consistent device names in the userspace (udev).

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
 drivers/net/arcnet/com20020-pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/arcnet/com20020-pci.c b/drivers/net/arcnet/com20020-pci.c
index fec2df2c869fe..47f80b83dcf42 100644
--- a/drivers/net/arcnet/com20020-pci.c
+++ b/drivers/net/arcnet/com20020-pci.c
@@ -167,6 +167,7 @@ static int com20020pci_probe(struct pci_dev *pdev,
 		arcnet_outb(0x00, ioaddr, COM20020_REG_W_COMMAND);
 		arcnet_inb(ioaddr, COM20020_REG_R_DIAGSTAT);
 
+		SET_NETDEV_DEV(dev, &pdev->dev);
 		dev->base_addr = ioaddr;
 		dev->dev_addr[0] = node;
 		dev->irq = pdev->irq;
-- 
2.11.0

Re: [PATCH 0/5] arcnet: Collection of latest fixes

[David Miller]

From: Michael Grzeschik <m.grzeschik@pengutronix.de>
Date: Wed, 28 Jun 2017 18:28:32 +0200

> Here we sum up the recent fixes I collected on the way to use and
> stabilise the framework. Part of it is an possible deadlock that we
> prevent as well to fix the calculation of the dev_id that can be setup
> by an rotary encoder. Beside that we added an trivial spelling patch and
> fix some wrong and missing assignments that improves the code footprint.

Series applied, thanks.