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RDS: Use spinlock to protect 64b value update on 32b archs

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We have a 64bit value that needs to be set atomically.
This is easy and quick on all 64bit archs, and can also be done
on x86/32 with set_64bit() (uses cmpxchg8b). However other
32b archs don't have this.

I actually changed this to the current state in preparation for
mainline because the old way (using a spinlock on 32b) resulted in
unsightly #ifdefs in the code. But obviously, being correct takes
precedence.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andy Grover
2009-04-01 08:20:20 +00:00
committed by David S. Miller
parent 745cbccac3
commit 8cbd9606a6
7 changed files with 100 additions and 24 deletions
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9
net/rds/iw_cm.c
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@@ -659,7 +659,11 @@ void rds_iw_conn_shutdown(struct rds_connection *conn)
/* Clear the ACK state */
clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
rds_iw_set_64bit(&ic->i_ack_next, 0);
#ifdef KERNEL_HAS_ATOMIC64
atomic64_set(&ic->i_ack_next, 0);
#else
ic->i_ack_next = 0;
#endif
ic->i_ack_recv = 0;
/* Clear flow control state */
@@ -693,6 +697,9 @@ int rds_iw_conn_alloc(struct rds_connection *conn, gfp_t gfp)
INIT_LIST_HEAD(&ic->iw_node);
mutex_init(&ic->i_recv_mutex);
#ifndef KERNEL_HAS_ATOMIC64
spin_lock_init(&ic->i_ack_lock);
#endif
/*
* rds_iw_conn_shutdown() waits for these to be emptied so they