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Subject[PATCH] net: davicom: dm9000: Avoid spinlock recursion during dm9000_timeout routine
Date
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 dm9000_phy_write()
during the dm9000_timeout() routine.

Signed-off-by: Liu Xiang <liu.xiang6@zte.com.cn>
---
drivers/net/ethernet/davicom/dm9000.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/davicom/dm9000.c b/drivers/net/ethernet/davicom/dm9000.c
index 008dc81..afe33de 100644
--- a/drivers/net/ethernet/davicom/dm9000.c
+++ b/drivers/net/ethernet/davicom/dm9000.c
@@ -337,11 +337,11 @@ static void dm9000_msleep(struct board_info *db, unsigned int ms)
unsigned long reg_save;

dm9000_dbg(db, 5, "phy_write[%02x] = %04x\n", reg, value);
- if (!db->in_timeout)
+ if (!db->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 +356,13 @@ 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 (!db->in_timeout)
+ spin_unlock_irqrestore(&db->lock, flags);

dm9000_msleep(db, 1); /* Wait write complete */

- spin_lock_irqsave(&db->lock, flags);
+ if (!db->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 +370,11 @@ 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 (!db->in_timeout) {
+ spin_unlock_irqrestore(&db->lock, flags);
+
mutex_unlock(&db->addr_lock);
+ }
}

/* dm9000_set_io
--
1.9.1
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