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Merge branch 'fixes-on-the-open-alliance-tc6-10base-t1x-mac-phy-support-generic-lib'

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Parthiban Veerasooran says:

====================
Fixes on the OPEN Alliance TC6 10BASE-T1x MAC-PHY support generic lib

This patch series contain the below fixes.

- Infinite loop error when tx credits becomes 0.
- Race condition between tx skb reference pointers.

v2:
- Added mutex lock to protect tx skb reference handling.

v3:
- Added mutex protection in assigning new tx skb to waiting_tx_skb
  pointer.
- Explained the possible scenario for the race condition with the time
  diagram in the commit message.

v4:
- Replaced mutex with spin_lock_bh() variants as the start_xmit runs in
  BH/softirq context which can't take sleeping locks.
====================

Link: https://patch.msgid.link/20241213123159.439739-1-parthiban.veerasooran@microchip.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Paolo Abeni 2024-12-17 13:11:35 +01:00
commit 90d130aadc
1 changed files with 9 additions and 2 deletions
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11
drivers/net/ethernet/oa_tc6.c
View File

@ -113,6 +113,7 @@ struct oa_tc6 {
struct mii_bus *mdiobus; struct mii_bus *mdiobus;
struct spi_device *spi; struct spi_device *spi;
struct mutex spi_ctrl_lock; /* Protects spi control transfer */ struct mutex spi_ctrl_lock; /* Protects spi control transfer */
spinlock_t tx_skb_lock; /* Protects tx skb handling */
void *spi_ctrl_tx_buf; void *spi_ctrl_tx_buf;
void *spi_ctrl_rx_buf; void *spi_ctrl_rx_buf;
void *spi_data_tx_buf; void *spi_data_tx_buf;
@ -1004,8 +1005,10 @@ static u16 oa_tc6_prepare_spi_tx_buf_for_tx_skbs(struct oa_tc6 *tc6)
for (used_tx_credits = 0; used_tx_credits < tc6->tx_credits; for (used_tx_credits = 0; used_tx_credits < tc6->tx_credits;
used_tx_credits++) { used_tx_credits++) {
if (!tc6->ongoing_tx_skb) { if (!tc6->ongoing_tx_skb) {
spin_lock_bh(&tc6->tx_skb_lock);
tc6->ongoing_tx_skb = tc6->waiting_tx_skb; tc6->ongoing_tx_skb = tc6->waiting_tx_skb;
tc6->waiting_tx_skb = NULL; tc6->waiting_tx_skb = NULL;
spin_unlock_bh(&tc6->tx_skb_lock);
} }
if (!tc6->ongoing_tx_skb) if (!tc6->ongoing_tx_skb)
break; break;
@ -1111,8 +1114,9 @@ static int oa_tc6_spi_thread_handler(void *data)
/* This kthread will be waken up if there is a tx skb or mac-phy /* This kthread will be waken up if there is a tx skb or mac-phy
* interrupt to perform spi transfer with tx chunks. * interrupt to perform spi transfer with tx chunks.
*/ */
wait_event_interruptible(tc6->spi_wq, tc6->waiting_tx_skb || wait_event_interruptible(tc6->spi_wq, tc6->int_flag ||
tc6->int_flag || (tc6->waiting_tx_skb &&
tc6->tx_credits) ||
kthread_should_stop()); kthread_should_stop());
if (kthread_should_stop()) if (kthread_should_stop())
@ -1209,7 +1213,9 @@ netdev_tx_t oa_tc6_start_xmit(struct oa_tc6 *tc6, struct sk_buff *skb)
return NETDEV_TX_OK; return NETDEV_TX_OK;
} }
spin_lock_bh(&tc6->tx_skb_lock);
tc6->waiting_tx_skb = skb; tc6->waiting_tx_skb = skb;
spin_unlock_bh(&tc6->tx_skb_lock);
/* Wake spi kthread to perform spi transfer */ /* Wake spi kthread to perform spi transfer */
wake_up_interruptible(&tc6->spi_wq); wake_up_interruptible(&tc6->spi_wq);
@ -1239,6 +1245,7 @@ struct oa_tc6 *oa_tc6_init(struct spi_device *spi, struct net_device *netdev)
tc6->netdev = netdev; tc6->netdev = netdev;
SET_NETDEV_DEV(netdev, &spi->dev); SET_NETDEV_DEV(netdev, &spi->dev);
mutex_init(&tc6->spi_ctrl_lock); mutex_init(&tc6->spi_ctrl_lock);
spin_lock_init(&tc6->tx_skb_lock);
/* Set the SPI controller to pump at realtime priority */ /* Set the SPI controller to pump at realtime priority */
tc6->spi->rt = true; tc6->spi->rt = true;