redonkable/alistair23-linux
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[PATCH] iseries_veth: Replace lock-protected atomic with an ordinary variable

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The iseries_veth driver uses atomic ops to manipulate the in_use field of
one of its per-connection structures. However all references to the
flag occur while the connection's lock is held, so the atomic ops aren't
necessary.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
This commit is contained in:
Michael Ellerman 2005-09-01 11:29:06 +10:00 committed by Jeff Garzik
parent d7893ddd1b
commit b08bd5c0a3
1 changed files with 7 additions and 6 deletions
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13
drivers/net/iseries_veth.c
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@ -117,7 +117,7 @@ struct veth_msg {
struct veth_msg *next;
struct VethFramesData data;
int token;
unsigned long in_use;
int in_use;
struct sk_buff *skb;
struct device *dev;
};
@ -957,6 +957,8 @@ static int veth_transmit_to_one(struct sk_buff *skb, HvLpIndex rlp,
goto drop;
}
msg->in_use = 1;
dma_length = skb->len;
dma_address = dma_map_single(port->dev, skb->data,
dma_length, DMA_TO_DEVICE);
@ -971,7 +973,6 @@ static int veth_transmit_to_one(struct sk_buff *skb, HvLpIndex rlp,
msg->data.addr[0] = dma_address;
msg->data.len[0] = dma_length;
msg->data.eofmask = 1 << VETH_EOF_SHIFT;
set_bit(0, &(msg->in_use));
rc = veth_signaldata(cnx, VethEventTypeFrames, msg->token, &msg->data);
if (rc != HvLpEvent_Rc_Good)
@ -981,10 +982,8 @@ static int veth_transmit_to_one(struct sk_buff *skb, HvLpIndex rlp,
return 0;
recycle_and_drop:
/* we free the skb below, so tell veth_recycle_msg() not to. */
msg->skb = NULL;
/* need to set in use to make veth_recycle_msg in case this
* was a mapping failure */
set_bit(0, &msg->in_use);
veth_recycle_msg(cnx, msg);
drop:
port->stats.tx_errors++;
@ -1066,12 +1065,14 @@ static int veth_start_xmit(struct sk_buff *skb, struct net_device *dev)
return 0;
}
/* You must hold the connection's lock when you call this function. */
static void veth_recycle_msg(struct veth_lpar_connection *cnx,
struct veth_msg *msg)
{
u32 dma_address, dma_length;
if (test_and_clear_bit(0, &msg->in_use)) {
if (msg->in_use) {
msg->in_use = 0;
dma_address = msg->data.addr[0];
dma_length = msg->data.len[0];