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/ixgbevf/ixgbevf_main.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c index 757dac6..29b71a7 100644 --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c @@ -719,12 +719,6 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring, /* update next to alloc since we have filled the ring */ rx_ring->next_to_alloc = 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, rx_ring->tail); } } @@ -1228,10 +1222,6 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, struct ixgbevf_ring *xdp_ring = adapter->xdp_ring[rx_ring->queue_index]; - /* Force memory writes to complete before letting h/w - * know there are new descriptors to fetch. - */ - wmb(); writel(xdp_ring->next_to_use, xdp_ring->tail); } @@ -3985,11 +3975,7 @@ static void ixgbevf_tx_map(struct ixgbevf_ring *tx_ring, /* set the timestamp */ first->time_stamp = jiffies; - /* 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 also need this memory barrier (wmb) to make certain all of the + /* We also need this memory barrier (wmb) to make certain all of the * status bits have been updated before next_to_watch is written. */ wmb(); @@ -4004,7 +3990,12 @@ static void ixgbevf_tx_map(struct ixgbevf_ring *tx_ring, tx_ring->next_to_use = i; /* notify HW of packet */ - writel(i, tx_ring->tail); + writel_relaxed(i, 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 + */ + mmiowb(); return; dma_error: -- 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
