On the DM9000B, dm9000_phy_write() is called after the main spinlock
is held, during the dm9000_timeout() routine. Spinlock recursion
occurs because the main spinlock is requested again in
dm9000_phy_write(). So spinlock should be avoided in phy operation
during the dm9000_timeout() routine.
---
v3:
When a task enters dm9000_timeout() and gets the main spinlock,
another task that wants to do asynchronous phy operation must be
running on another cpu.Because of different cpus, this
asynchronous task will be blocked in dm9000_phy_write() until
dm9000_timeout() routine is completed.
---
Signed-off-by: Liu Xiang <liu.xia...@zte.com.cn>
---
drivers/net/ethernet/davicom/dm9000.c | 39 +++++++++++++++++++++++++----------
1 file changed, 28 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ethernet/davicom/dm9000.c
b/drivers/net/ethernet/davicom/dm9000.c
index 50222b7..56df77d 100644
--- a/drivers/net/ethernet/davicom/dm9000.c
+++ b/drivers/net/ethernet/davicom/dm9000.c
@@ -112,7 +112,7 @@ struct board_info {
u8 imr_all;
unsigned int flags;
- unsigned int in_timeout:1;
+ int timeout_cpu;
unsigned int in_suspend:1;
unsigned int wake_supported:1;
@@ -158,6 +158,17 @@ static inline struct board_info *to_dm9000_board(struct
net_device *dev)
return netdev_priv(dev);
}
+static bool dm9000_current_in_timeout(struct board_info *db)
+{
+ bool ret = false;
+
+ preempt_disable();
+ ret = (db->timeout_cpu == smp_processor_id());
+ preempt_enable();
+
+ return ret;
+}
+
/* DM9000 network board routine ---------------------------- */
/*
@@ -276,7 +287,7 @@ static void dm9000_dumpblk_32bit(void __iomem *reg, int
count)
*/
static void dm9000_msleep(struct board_info *db, unsigned int ms)
{
- if (db->in_suspend || db->in_timeout)
+ if (db->in_suspend || dm9000_current_in_timeout(db))
mdelay(ms);
else
msleep(ms);
@@ -335,12 +346,13 @@ static void dm9000_msleep(struct board_info *db, unsigned
int ms)
struct board_info *db = netdev_priv(dev);
unsigned long flags;
unsigned long reg_save;
+ bool in_timeout = dm9000_current_in_timeout(db);
dm9000_dbg(db, 5, "phy_write[%02x] = %04x\n", reg, value);
- if (!db->in_timeout)
+ if (!in_timeout) {
mutex_lock(&db->addr_lock);
-
- spin_lock_irqsave(&db->lock, flags);
+ spin_lock_irqsave(&db->lock, flags);
+ }
/* Save previous register address */
reg_save = readb(db->io_addr);
@@ -356,11 +368,13 @@ static void dm9000_msleep(struct board_info *db, unsigned
int ms)
iow(db, DM9000_EPCR, EPCR_EPOS | EPCR_ERPRW);
writeb(reg_save, db->io_addr);
- spin_unlock_irqrestore(&db->lock, flags);
+ if (!in_timeout)
+ spin_unlock_irqrestore(&db->lock, flags);
dm9000_msleep(db, 1); /* Wait write complete */
- spin_lock_irqsave(&db->lock, flags);
+ if (!in_timeout)
+ spin_lock_irqsave(&db->lock, flags);
reg_save = readb(db->io_addr);
iow(db, DM9000_EPCR, 0x0); /* Clear phyxcer write command */
@@ -368,9 +382,10 @@ static void dm9000_msleep(struct board_info *db, unsigned
int ms)
/* restore the previous address */
writeb(reg_save, db->io_addr);
- spin_unlock_irqrestore(&db->lock, flags);
- if (!db->in_timeout)
+ if (!in_timeout) {
+ spin_unlock_irqrestore(&db->lock, flags);
mutex_unlock(&db->addr_lock);
+ }
}
/* dm9000_set_io
@@ -980,7 +995,7 @@ static void dm9000_timeout(struct net_device *dev)
/* Save previous register address */
spin_lock_irqsave(&db->lock, flags);
- db->in_timeout = 1;
+ db->timeout_cpu = smp_processor_id();
reg_save = readb(db->io_addr);
netif_stop_queue(dev);
@@ -992,7 +1007,7 @@ static void dm9000_timeout(struct net_device *dev)
/* Restore previous register address */
writeb(reg_save, db->io_addr);
- db->in_timeout = 0;
+ db->timeout_cpu = -1;
spin_unlock_irqrestore(&db->lock, flags);
}
@@ -1670,6 +1685,8 @@ static struct dm9000_plat_data *dm9000_parse_dt(struct
device *dev)
db->mii.mdio_read = dm9000_phy_read;
db->mii.mdio_write = dm9000_phy_write;
+ db->timeout_cpu = -1;
+
mac_src = "eeprom";
/* try reading the node address from the attached EEPROM */
--
1.9.1
