Messages in this thread Patch in this message |  | | | Date | Thu, 30 Jun 2005 20:20:39 +1000 | | From | Michael Ellerman <> | | Subject | [PATCH 8/12] 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.
--- drivers/net/iseries_veth.c | 13 +++++++------ 1 files changed, 7 insertions(+), 6 deletions(-) Index: veth-dev/drivers/net/iseries_veth.c =================================================================== --- veth-dev.orig/drivers/net/iseries_veth.c +++ veth-dev/drivers/net/iseries_veth.c @@ -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; }; @@ -959,6 +959,8 @@ static int veth_transmit_to_one(struct s goto drop; } + msg->in_use = 1; + dma_length = skb->len; dma_address = dma_map_single(port->dev, skb->data, dma_length, DMA_TO_DEVICE); @@ -973,7 +975,6 @@ static int veth_transmit_to_one(struct s 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) @@ -983,10 +984,8 @@ static int veth_transmit_to_one(struct s 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++; @@ -1068,12 +1067,14 @@ static int veth_start_xmit(struct sk_buf 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]; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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