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Commit b08bd5c0 authored by Michael Ellerman's avatar Michael Ellerman Committed by Jeff Garzik
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[PATCH] iseries_veth: Replace lock-protected atomic with an ordinary variable 



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: default avatarMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: default avatarJeff Garzik <jgarzik@pobox.com>
parent d7893ddd

drivers/net/iseries_veth.c

+7 −6
Original line number Diff line number Diff line
@@ -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];