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authorJulian Wiedmann <jwi@linux.ibm.com>2020-09-23 10:36:56 +0200
committerDavid S. Miller <davem@davemloft.net>2020-09-23 12:07:54 -0700
commitf3380b1edc1dd06d874227570a5fe0fbf50eb607 (patch)
tree8df096b76fe9a3caa4e2f196619deac3fcc815bc /fs/bad_inode.c
parentab29c480b19465a5174ea8eddfa1bd42becf72c9 (diff)
s390/qeth: tighten ucast IP locking
The programming of ucast IPs via qeth_l3_modify_ip() is driven independently from any of our typical locking mechanisms (eg. detaching the netdevice, or holding the conf_mutex). So when we inspect the card state to check whether the required cmd IO should be deferred, there is no protection against concurrent state changes. But by slightly re-ordering the teardown sequence, we can rely on the ip_lock to sufficiently serialize things: 1. when running concurrently to qeth_l3_set_online(), any instance of qeth_l3_modify_ip() that aquires the ip_lock _after_ qeth_l3_recover_ip() will observe the state as CARD_STATE_SOFTSETUP and not defer the IO. 2. when running concurrently to qeth_l3_set_offline(), any instance of qeth_l3_modify_ip() that aquires the ip_lock _after_ qeth_l3_clear_ip_htable() will observe the state as CARD_STATE_DOWN and defer the IO. These guarantees in mind, we can now drop the conf_mutex from the qeth_l3_modify_rxip_vipa() wrapper. Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'fs/bad_inode.c')
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