net/smc: fix sleep bug in smc_pnet_find_roce_resource()
Tests showed this BUG:
[572555.252867] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
[572555.252876] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 131031, name: smcapp
[572555.252879] INFO: lockdep is turned off.
[572555.252883] CPU: 1 PID: 131031 Comm: smcapp Tainted: G O 5.7.0-rc3uschi+ #356
[572555.252885] Hardware name: IBM 3906 M03 703 (LPAR)
[572555.252887] Call Trace:
[572555.252896] [<
00000000ac364554>] show_stack+0x94/0xe8
[572555.252901] [<
00000000aca1f400>] dump_stack+0xa0/0xe0
[572555.252906] [<
00000000ac3c8c10>] ___might_sleep+0x260/0x280
[572555.252910] [<
00000000acdc0c98>] __mutex_lock+0x48/0x940
[572555.252912] [<
00000000acdc15c2>] mutex_lock_nested+0x32/0x40
[572555.252975] [<
000003ff801762d0>] mlx5_lag_get_roce_netdev+0x30/0xc0 [mlx5_core]
[572555.252996] [<
000003ff801fb3aa>] mlx5_ib_get_netdev+0x3a/0xe0 [mlx5_ib]
[572555.253007] [<
000003ff80063848>] smc_pnet_find_roce_resource+0x1d8/0x310 [smc]
[572555.253011] [<
000003ff800602f0>] __smc_connect+0x1f0/0x3e0 [smc]
[572555.253015] [<
000003ff80060634>] smc_connect+0x154/0x190 [smc]
[572555.253022] [<
00000000acbed8d4>] __sys_connect+0x94/0xd0
[572555.253025] [<
00000000acbef620>] __s390x_sys_socketcall+0x170/0x360
[572555.253028] [<
00000000acdc6800>] system_call+0x298/0x2b8
[572555.253030] INFO: lockdep is turned off.
Function smc_pnet_find_rdma_dev() might be called from
smc_pnet_find_roce_resource(). It holds the smc_ib_devices list
spinlock while calling infiniband op get_netdev(). At least for mlx5
the get_netdev operation wants mutex serialization, which conflicts
with the smc_ib_devices spinlock.
This patch switches the smc_ib_devices spinlock into a mutex to
allow sleeping when calling get_netdev().
Fixes:
a4cf0443c414 ("smc: introduce SMC as an IB-client")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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