Re: [PATCH net-next v1 1/1] net: dsa: ar9331: fix potential dead lock on mdio access
From: Oleksij Rempel <o.rempel@pengutronix.de>
Date: 2022-06-16 15:31:17
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On Thu, Jun 16, 2022 at 03:34:18PM +0200, Andrew Lunn wrote:
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static int ar9331_mdio_read(void *ctx, const void *reg_buf, size_t reg_len,@@ -849,6 +849,8 @@ static int ar9331_mdio_read(void *ctx, const void *reg_buf, size_t reg_len, return 0; } + mutex_lock_nested(&sbus->mdio_lock, MDIO_MUTEX_NESTED); +Do you know about mdiobus_read_nested() and mdiobus_write_nested(). The mv88e6xxx driver uses these.
Yes. I need at least 2 master MDIO accesses to implement 1 slave mdio access. So I decided to get lock one time for all needed accesses instead of taking it multiple times. Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |