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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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14
net/rds/ib.h
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@ -108,7 +108,12 @@ struct rds_ib_connection {
/* sending acks */
unsigned long i_ack_flags;
#ifdef KERNEL_HAS_ATOMIC64
atomic64_t i_ack_next; /* next ACK to send */
#else
spinlock_t i_ack_lock; /* protect i_ack_next */
u64 i_ack_next; /* next ACK to send */
#endif
struct rds_header *i_ack;
struct ib_send_wr i_ack_wr;
struct ib_sge i_ack_sge;
@ -363,13 +368,4 @@ rds_ib_data_sge(struct rds_ib_connection *ic, struct ib_sge *sge)
return &sge[1];
}
static inline void rds_ib_set_64bit(u64 *ptr, u64 val)
{
#if BITS_PER_LONG == 64
*ptr = val;
#else
set_64bit(ptr, val);
#endif
}
#endif