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authorBen Hutchings <ben.hutchings@codethink.co.uk>2015-01-22 15:44:08 +0300
committerDavid S. Miller <davem@davemloft.net>2015-01-27 03:13:15 +0300
commit283e38db65e77be9bbe2d455452584ee7834e4e9 (patch)
treef1997cddb44f8d5fe7316658e9d0556f47a40051 /drivers/w1/masters
parent084236d8c53952f14b5cb1741311c80c7fbe8289 (diff)
downloadlinux-283e38db65e77be9bbe2d455452584ee7834e4e9.tar.xz
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 <ben.hutchings@codethink.co.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/w1/masters')
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