memory-barriers.txt has been updated as follows: "When using writel(), a prior wmb() is not needed to guarantee that the cache coherent memory writes have completed before writing to the MMIO region." Remove old IA-64 comments in the code along with unneeded wmb() in front of writel(). There are places in the code where wmb() has been used as a double barrier for CPU and IO in place of smp_wmb() and wmb() as an optimization. For such places, keep the wmb() but replace the following writel() with writel_relaxed() to have a sequence as wmb() writel_relaxed() mmio_wb() Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx> --- drivers/net/ethernet/intel/igbvf/netdev.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/drivers/net/ethernet/intel/igbvf/netdev.c b/drivers/net/ethernet/intel/igbvf/netdev.c index e2b7502..d9f186a 100644 --- a/drivers/net/ethernet/intel/igbvf/netdev.c +++ b/drivers/net/ethernet/intel/igbvf/netdev.c @@ -246,12 +246,6 @@ static void igbvf_alloc_rx_buffers(struct igbvf_ring *rx_ring, else i--; - /* Force memory writes to complete before letting h/w - * know there are new descriptors to fetch. (Only - * applicable for weak-ordered memory model archs, - * such as IA-64). - */ - wmb(); writel(i, adapter->hw.hw_addr + rx_ring->tail); } } @@ -2289,16 +2283,16 @@ static inline void igbvf_tx_queue_adv(struct igbvf_adapter *adapter, } tx_desc->read.cmd_type_len |= cpu_to_le32(adapter->txd_cmd); - /* Force memory writes to complete before letting h/w - * know there are new descriptors to fetch. (Only - * applicable for weak-ordered memory model archs, - * such as IA-64). + + /* We use this memory barrier to make certain all of the + * status bits have been updated before next_to_watch is + * written. */ wmb(); tx_ring->buffer_info[first].next_to_watch = tx_desc; tx_ring->next_to_use = i; - writel(i, adapter->hw.hw_addr + tx_ring->tail); + writel_relaxed(i, adapter->hw.hw_addr + tx_ring->tail); /* we need this if more than one processor can write to our tail * at a time, it synchronizes IO on IA64/Altix systems */ -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
