From 283e38db65e77be9bbe2d455452584ee7834e4e9 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 22 Jan 2015 12:44:08 +0000 Subject: sh_eth: Fix serialisation of interrupt disable with interrupt & NAPI handlers In order to stop the RX path accessing the RX ring while it's being stopped or resized, we clear the interrupt mask (EESIPR) and then call free_irq() or synchronise_irq(). This is insufficient because the interrupt handler or NAPI poller may set EESIPR again after we clear it. Also, in sh_eth_set_ringparam() we currently don't disable NAPI polling at all. I could easily trigger a crash by running the loop: while ethtool -G eth0 rx 128 && ethtool -G eth0 rx 64; do echo -n .; done and 'ping -f' toward the sh_eth port from another machine. To fix this: - Add a software flag (irq_enabled) to signal whether interrupts should be enabled - In the interrupt handler, if the flag is clear then clear EESIPR and return - In the NAPI poller, if the flag is clear then don't set EESIPR - Set the flag before enabling interrupts in sh_eth_dev_init() and sh_eth_set_ringparam() - Clear the flag and serialise with the interrupt and NAPI handlers before clearing EESIPR in sh_eth_close() and sh_eth_set_ringparam() After this, I could run the loop for 100,000 iterations successfully. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/sh_eth.h | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/net/ethernet/renesas/sh_eth.h') diff --git a/drivers/net/ethernet/renesas/sh_eth.h b/drivers/net/ethernet/renesas/sh_eth.h index 71f5de1171bd..332d3c16d483 100644 --- a/drivers/net/ethernet/renesas/sh_eth.h +++ b/drivers/net/ethernet/renesas/sh_eth.h @@ -513,6 +513,7 @@ struct sh_eth_private { u32 rx_buf_sz; /* Based on MTU+slack. */ int edmac_endian; struct napi_struct napi; + bool irq_enabled; /* MII transceiver section. */ u32 phy_id; /* PHY ID */ struct mii_bus *mii_bus; /* MDIO bus control */ -- cgit v1.2.3