[PATCH AUTOSEL 5.4 194/330] net: axienet: Convert DMA error handler to a work queue

Sasha Levin
2020-09-18T02:05:16Z

From: Andre Przywara <andre.przywara@arm.com>

[ Upstream commit 24201a64770afe2e17050b2ab9e8c0e24e9c23b2 ]

The DMA error handler routine is currently a tasklet, scheduled to run
after the DMA error IRQ was handled.
However it needs to take the MDIO mutex, which is not allowed to do in a
tasklet. A kernel (with debug options) complains consequently:
[ 614.050361] net eth0: DMA Tx error 0x174019
[ 614.064002] net eth0: Current BD is at: 0x8f84aa0ce
[ 614.080195] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
[ 614.109484] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 40, name: kworker/u4:4
[ 614.135428] 3 locks held by kworker/u4:4/40:
[ 614.149075] #0: ffff000879863328 ((wq_completion)rpciod){....}, at: process_one_work+0x1f0/0x6a8
[ 614.177528] #1: ffff80001251bdf8 ((work_completion)(&task->u.tk_work)){....}, at: process_one_work+0x1f0/0x6a8
[ 614.209033] #2: ffff0008784e0110 (sk_lock-AF_INET-RPC){....}, at: tcp_sendmsg+0x24/0x58
[ 614.235429] CPU: 0 PID: 40 Comm: kworker/u4:4 Not tainted 5.6.0-rc3-00926-g4a165a9d5921 #26
[ 614.260854] Hardware name: ARM Test FPGA (DT)
[ 614.274734] Workqueue: rpciod rpc_async_schedule
[ 614.289022] Call trace:
[ 614.296871] dump_backtrace+0x0/0x1a0
[ 614.308311] show_stack+0x14/0x20
[ 614.318751] dump_stack+0xbc/0x100
[ 614.329403] ___might_sleep+0xf0/0x140
[ 614.341018] __might_sleep+0x4c/0x80
[ 614.352201] __mutex_lock+0x5c/0x8a8
[ 614.363348] mutex_lock_nested+0x1c/0x28
[ 614.375654] axienet_dma_err_handler+0x38/0x388
[ 614.389999] tasklet_action_common.isra.15+0x160/0x1a8
[ 614.405894] tasklet_action+0x24/0x30
[ 614.417297] efi_header_end+0xe0/0x494
[ 614.429020] irq_exit+0xd0/0xd8
[ 614.439047] __handle_domain_irq+0x60/0xb0
[ 614.451877] gic_handle_irq+0xdc/0x2d0
[ 614.463486] el1_irq+0xcc/0x180
[ 614.473451] __tcp_transmit_skb+0x41c/0xb58
[ 614.486513] tcp_write_xmit+0x224/0x10a0
[ 614.498792] __tcp_push_pending_frames+0x38/0xc8
[ 614.513126] tcp_rcv_established+0x41c/0x820
[ 614.526301] tcp_v4_do_rcv+0x8c/0x218
[ 614.537784] __release_sock+0x5c/0x108
[ 614.549466] release_sock+0x34/0xa0
[ 614.560318] tcp_sendmsg+0x40/0x58
[ 614.571053] inet_sendmsg+0x40/0x68
[ 614.582061] sock_sendmsg+0x18/0x30
[ 614.593074] xs_sendpages+0x218/0x328
[ 614.604506] xs_tcp_send_request+0xa0/0x1b8
[ 614.617461] xprt_transmit+0xc8/0x4f0
[ 614.628943] call_transmit+0x8c/0xa0
[ 614.640028] __rpc_execute+0xbc/0x6f8
[ 614.651380] rpc_async_schedule+0x28/0x48
[ 614.663846] process_one_work+0x298/0x6a8
[ 614.676299] worker_thread+0x40/0x490
[ 614.687687] kthread+0x134/0x138
[ 614.697804] ret_from_fork+0x10/0x18
[ 614.717319] xilinx_axienet 7fe00000.ethernet eth0: Link is Down
[ 615.748343] xilinx_axienet 7fe00000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off

Since tasklets are not really popular anymore anyway, lets convert this
over to a work queue, which can sleep and thus can take the MDIO mutex.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/xilinx/xilinx_axienet.h | 2 +-
.../net/ethernet/xilinx/xilinx_axienet_main.c | 24 +++++++++----------
2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h
index 2dacfc85b3baa..04e51af32178c 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet.h
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h
@@ -435,7 +435,7 @@ struct axienet_local {
void __iomem *regs;
void __iomem *dma_regs;

- struct tasklet_struct dma_err_tasklet;
+ struct work_struct dma_err_task;

int tx_irq;
int rx_irq;
diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 479325eeaf8a0..345a795666e92 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -806,7 +806,7 @@ static irqreturn_t axienet_tx_irq(int irq, void *_ndev)
/* Write to the Rx channel control register */
axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET, cr);

- tasklet_schedule(&lp->dma_err_tasklet);
+ schedule_work(&lp->dma_err_task);
axienet_dma_out32(lp, XAXIDMA_TX_SR_OFFSET, status);
}
out:
@@ -855,7 +855,7 @@ static irqreturn_t axienet_rx_irq(int irq, void *_ndev)
/* write to the Rx channel control register */
axienet_dma_out32(lp, XAXIDMA_RX_CR_OFFSET, cr);

- tasklet_schedule(&lp->dma_err_tasklet);
+ schedule_work(&lp->dma_err_task);
axienet_dma_out32(lp, XAXIDMA_RX_SR_OFFSET, status);
}
out:
@@ -891,7 +891,7 @@ static irqreturn_t axienet_eth_irq(int irq, void *_ndev)
return IRQ_HANDLED;
}

-static void axienet_dma_err_handler(unsigned long data);
+static void axienet_dma_err_handler(struct work_struct *work);

/**
* axienet_open - Driver open routine.
@@ -935,9 +935,8 @@ static int axienet_open(struct net_device *ndev)

phylink_start(lp->phylink);

- /* Enable tasklets for Axi DMA error handling */
- tasklet_init(&lp->dma_err_tasklet, axienet_dma_err_handler,
- (unsigned long) lp);
+ /* Enable worker thread for Axi DMA error handling */
+ INIT_WORK(&lp->dma_err_task, axienet_dma_err_handler);

/* Enable interrupts for Axi DMA Tx */
ret = request_irq(lp->tx_irq, axienet_tx_irq, IRQF_SHARED,
@@ -966,7 +965,7 @@ err_rx_irq:
err_tx_irq:
phylink_stop(lp->phylink);
phylink_disconnect_phy(lp->phylink);
- tasklet_kill(&lp->dma_err_tasklet);
+ cancel_work_sync(&lp->dma_err_task);
dev_err(lp->dev, "request_irq() failed\n");
return ret;
}
@@ -1025,7 +1024,7 @@ static int axienet_stop(struct net_device *ndev)
axienet_mdio_enable(lp);
mutex_unlock(&lp->mii_bus->mdio_lock);

- tasklet_kill(&lp->dma_err_tasklet);
+ cancel_work_sync(&lp->dma_err_task);

if (lp->eth_irq > 0)
free_irq(lp->eth_irq, ndev);
@@ -1505,17 +1504,18 @@ static const struct phylink_mac_ops axienet_phylink_ops = {
};

/**
- * axienet_dma_err_handler - Tasklet handler for Axi DMA Error
- * @data: Data passed
+ * axienet_dma_err_handler - Work queue task for Axi DMA Error
+ * @work: pointer to work_struct
*
* Resets the Axi DMA and Axi Ethernet devices, and reconfigures the
* Tx/Rx BDs.
*/
-static void axienet_dma_err_handler(unsigned long data)
+static void axienet_dma_err_handler(struct work_struct *work)
{
u32 axienet_status;
u32 cr, i;
- struct axienet_local *lp = (struct axienet_local *) data;
+ struct axienet_local *lp = container_of(work, struct axienet_local,
+ dma_err_task);
struct net_device *ndev = lp->ndev;
struct axidma_bd *cur_p;

--
2.25.1