net/smc: fix wait on already cleared link

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[ Upstream commit 8f3d65c166 ]

There can be a race between the waiters for a tx work request buffer
and the link down processing that finally clears the link. Although
all waiters are woken up before the link is cleared there might be
waiters which did not yet get back control and are still waiting.
This results in an access to a cleared wait queue head.

Fix this by introducing atomic reference counting around the wait calls,
and wait with the link clear processing until all waiters have finished.
Move the work request layer related calls into smc_wr.c and set the
link state to INACTIVE before calling smcr_link_clear() in
smc_llc_srv_add_link().

Fixes: 15e1b99aad ("net/smc: no WR buffer wait for terminating link group")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Guvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Karsten Graul 2021-08-09 11:05:56 +02:00 • committed by Greg Kroah-Hartman

parent 51f4965d77

commit f15f7716b0

4 changed files with 33 additions and 7 deletions

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2

net/smc/smc_core.h

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10

net/smc/smc_llc.c

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18

net/smc/smc_tx.c

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10

net/smc/smc_wr.c

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