From: Roland Dreier Add a mthca_write_db_rec() to wrap writing doorbell records. On 64-bit archs, this is just a 64-bit write, while on 32-bit archs it splits the write into two 32-bit writes with a memory barrier to make sure the two halves of the record are written in the correct order. Signed-off-by: Roland Dreier Signed-off-by: Andrew Morton --- 25-akpm/drivers/infiniband/hw/mthca/mthca_doorbell.h | 12 ++++++++++++ 1 files changed, 12 insertions(+) diff -puN drivers/infiniband/hw/mthca/mthca_doorbell.h~ib-mthca-mem-free-doorbell-record-writing drivers/infiniband/hw/mthca/mthca_doorbell.h --- 25/drivers/infiniband/hw/mthca/mthca_doorbell.h~ib-mthca-mem-free-doorbell-record-writing 2005-03-03 17:40:09.000000000 -0800 +++ 25-akpm/drivers/infiniband/hw/mthca/mthca_doorbell.h 2005-03-03 17:40:09.000000000 -0800 @@ -57,6 +57,11 @@ static inline void mthca_write64(u32 val __raw_writeq(*(u64 *) val, dest); } +static inline void mthca_write_db_rec(u32 val[2], u32 *db) +{ + *(u64 *) db = *(u64 *) val; +} + #else /* @@ -80,4 +85,11 @@ static inline void mthca_write64(u32 val spin_unlock_irqrestore(doorbell_lock, flags); } +static inline void mthca_write_db_rec(u32 val[2], u32 *db) +{ + db[0] = val[0]; + wmb(); + db[1] = val[1]; +} + #endif _