[PATCH v8 RESEND 5/6] r8169: Use mutex to guard config register locking

From: Kai-Heng Feng
Date: Mon Feb 20 2023 - 21:40:44 EST


Right now r8169 doesn't have parallel access to its config register, but
the next patch makes the driver access config register at anytime.

So add a mutex to protect the config register from any potential race.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
---
v8:
- Swap the place when using the mutex. Protect when config register is
unlocked.

v7:
- This is a new patch.

drivers/net/ethernet/realtek/r8169_main.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index e40498dd08d17..897f90b48bba6 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -613,6 +613,8 @@ struct rtl8169_private {
struct work_struct work;
} wk;

+ struct mutex config_lock;
+
unsigned supports_gmii:1;
unsigned aspm_manageable:1;
dma_addr_t counters_phys_addr;
@@ -662,10 +664,12 @@ static inline struct device *tp_to_dev(struct rtl8169_private *tp)
static void rtl_lock_config_regs(struct rtl8169_private *tp)
{
RTL_W8(tp, Cfg9346, Cfg9346_Lock);
+ mutex_unlock(&tp->config_lock);
}

static void rtl_unlock_config_regs(struct rtl8169_private *tp)
{
+ mutex_lock(&tp->config_lock);
RTL_W8(tp, Cfg9346, Cfg9346_Unlock);
}

@@ -5217,6 +5221,8 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
return rc;
}

+ mutex_init(&tp->config_lock);
+
tp->mmio_addr = pcim_iomap_table(pdev)[region];

xid = (RTL_R32(tp, TxConfig) >> 20) & 0xfcf;
--
2.34.1