提交 c298ede2 编写于 作者: D Doug Berger 提交者: David S. Miller

net: bcmgenet: simplify circular pointer arithmetic

A 2's complement subtraction will always do a borrow, so masking
off the sign bits is the same as conditionally adding (mask+1).
Signed-off-by: NDoug Berger <opendmb@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 83ee102a
/*
* Broadcom GENET (Gigabit Ethernet) controller driver
*
* Copyright (c) 2014 Broadcom Corporation
* Copyright (c) 2014-2017 Broadcom
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
......@@ -1175,13 +1175,9 @@ static unsigned int __bcmgenet_tx_reclaim(struct net_device *dev,
unsigned int txbds_processed = 0;
/* Compute how many buffers are transmitted since last xmit call */
c_index = bcmgenet_tdma_ring_readl(priv, ring->index, TDMA_CONS_INDEX);
c_index &= DMA_C_INDEX_MASK;
if (likely(c_index >= ring->c_index))
txbds_ready = c_index - ring->c_index;
else
txbds_ready = (DMA_C_INDEX_MASK + 1) - ring->c_index + c_index;
c_index = bcmgenet_tdma_ring_readl(priv, ring->index, TDMA_CONS_INDEX)
& DMA_C_INDEX_MASK;
txbds_ready = (c_index - ring->c_index) & DMA_C_INDEX_MASK;
netif_dbg(priv, tx_done, dev,
"%s ring=%d old_c_index=%u c_index=%u txbds_ready=%u\n",
......@@ -1611,12 +1607,7 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_rx_ring *ring,
}
p_index &= DMA_P_INDEX_MASK;
if (likely(p_index >= ring->c_index))
rxpkttoprocess = p_index - ring->c_index;
else
rxpkttoprocess = (DMA_C_INDEX_MASK + 1) - ring->c_index +
p_index;
rxpkttoprocess = (p_index - ring->c_index) & DMA_C_INDEX_MASK;
netif_dbg(priv, rx_status, dev,
"RDMA: rxpkttoprocess=%d\n", rxpkttoprocess);
......
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