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Commit 0e2ad69b authored by Sven Van Asbroeck's avatar Sven Van Asbroeck Committed by Greg Kroah-Hartman
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lan743x: fix "BUG: invalid wait context" when setting rx mode 



[ Upstream commit 2b52a4b65bc8f14520fe6e996ea7fb3f7e400761 ]

In the net core, the struct net_device_ops -> ndo_set_rx_mode()
callback is called with the dev->addr_list_lock spinlock held.

However, this driver's ndo_set_rx_mode callback eventually calls
lan743x_dp_write(), which acquires a mutex. Mutex acquisition
may sleep, and this is not allowed when holding a spinlock.

Fix by removing the dp_lock mutex entirely. Its purpose is to
prevent concurrent accesses to the data port. No concurrent
accesses are possible, because the dev->addr_list_lock
spinlock in the core only lets through one thread at a time.

Fixes: 23f0703c ("lan743x: Add main source files for new lan743x driver")
Signed-off-by: default avatarSven Van Asbroeck <thesven73@gmail.com>
Link: https://lore.kernel.org/r/20201109203828.5115-1-TheSven73@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent b45f52a2

drivers/net/ethernet/microchip/lan743x_main.c

+3 −9
Original line number Diff line number Diff line
@@ -672,14 +672,12 @@ static int lan743x_intr_open(struct lan743x_adapter *adapter) 
static int lan743x_dp_write(struct lan743x_adapter *adapter,

			    u32 select, u32 addr, u32 length, u32 *buf)

{

	int ret = -EIO;

	u32 dp_sel;

	int i;



	mutex_lock(&adapter->dp_lock);

	if (lan743x_csr_wait_for_bit(adapter, DP_SEL, DP_SEL_DPRDY_,

				     1, 40, 100, 100))

		goto unlock;

		return -EIO;

	dp_sel = lan743x_csr_read(adapter, DP_SEL);

	dp_sel &= ~DP_SEL_MASK_;

	dp_sel |= select;
@@ -691,13 +689,10 @@ static int lan743x_dp_write(struct lan743x_adapter *adapter, 
		lan743x_csr_write(adapter, DP_CMD, DP_CMD_WRITE_);

		if (lan743x_csr_wait_for_bit(adapter, DP_SEL, DP_SEL_DPRDY_,

					     1, 40, 100, 100))

			goto unlock;

			return -EIO;

	}

	ret = 0;



unlock:

	mutex_unlock(&adapter->dp_lock);

	return ret;

	return 0;

}



static u32 lan743x_mac_mii_access(u16 id, u16 index, int read)
@@ -2674,7 +2669,6 @@ static int lan743x_hardware_init(struct lan743x_adapter *adapter, 


	adapter->intr.irq = adapter->pdev->irq;

	lan743x_csr_write(adapter, INT_EN_CLR, 0xFFFFFFFF);

	mutex_init(&adapter->dp_lock);



	ret = lan743x_gpio_init(adapter);

	if (ret)

drivers/net/ethernet/microchip/lan743x_main.h

+0 −3
Original line number Diff line number Diff line
@@ -706,9 +706,6 @@ struct lan743x_adapter { 
	struct lan743x_csr      csr;

	struct lan743x_intr     intr;



	/* lock, used to prevent concurrent access to data port */

	struct mutex		dp_lock;



	struct lan743x_gpio	gpio;

	struct lan743x_ptp	ptp;