On Sun, Mar 08, 2009 at 10:28:23AM +0100, Jiri Slaby wrote:
>> If you want I'll cook up a patch for that too.
>
> If you like, feel free to kick it off. Remember to remove bf->flags
> completely, so that we save another bunch of memory ;).
Ok, here's a patch, it survived a few hours of testing with 3 rx buffers.
Sitsofe, it's worth a try applying this one, even though it probably
isn't it :)
From: Bob Copeland <me@xxxxxxxxxxxxxxx>
Date: Mon, 9 Mar 2009 11:29:34 -0400
Subject: [PATCH] ath5k: use rx hw descriptor pointer for self-linked check
This patch simplifies the code used to detect when the
self-linked DMA buffer is still in use by hardware, by
checking the hardware's rxdp register instead of looking
at the software buffer list.
Signed-off-by: Bob Copeland <me@xxxxxxxxxxxxxxx>
---
drivers/net/wireless/ath5k/base.c | 24 ++++--------------------
drivers/net/wireless/ath5k/base.h | 1 -
drivers/net/wireless/ath5k/dma.c | 2 --
3 files changed, 4 insertions(+), 23 deletions(-)
diff --git a/drivers/net/wireless/ath5k/base.c b/drivers/net/wireless/ath5k/base.c
index 1d77ee9..a4e385b 100644
--- a/drivers/net/wireless/ath5k/base.c
+++ b/drivers/net/wireless/ath5k/base.c
@@ -1677,7 +1677,7 @@ ath5k_tasklet_rx(unsigned long data)
struct sk_buff *skb, *next_skb;
dma_addr_t next_skb_addr;
struct ath5k_softc *sc = (void *)data;
- struct ath5k_buf *bf, *bf_last;
+ struct ath5k_buf *bf;
struct ath5k_desc *ds;
int ret;
int hdrlen;
@@ -1688,7 +1688,6 @@ ath5k_tasklet_rx(unsigned long data)
ATH5K_WARN(sc, "empty rx buf pool\n");
goto unlock;
}
- bf_last = list_entry(sc->rxbuf.prev, struct ath5k_buf, list);
do {
rxs.flag = 0;
@@ -1697,24 +1696,9 @@ ath5k_tasklet_rx(unsigned long data)
skb = bf->skb;
ds = bf->desc;
- /*
- * last buffer must not be freed to ensure proper hardware
- * function. When the hardware finishes also a packet next to
- * it, we are sure, it doesn't use it anymore and we can go on.
- */
- if (bf_last == bf)
- bf->flags |= 1;
- if (bf->flags) {
- struct ath5k_buf *bf_next = list_entry(bf->list.next,
- struct ath5k_buf, list);
- ret = sc->ah->ah_proc_rx_desc(sc->ah, bf_next->desc,
- &rs);
- if (ret)
- break;
- bf->flags &= ~1;
- /* skip the overwritten one (even status is martian) */
- goto next;
- }
+ /* bail if HW is still using self-linked descriptor */
+ if (ath5k_hw_get_rxdp(sc->ah) == bf->daddr)
+ break;
ret = sc->ah->ah_proc_rx_desc(sc->ah, ds, &rs);
if (unlikely(ret == -EINPROGRESS))
diff --git a/drivers/net/wireless/ath5k/base.h b/drivers/net/wireless/ath5k/base.h
index facc60d..ed407cc 100644
--- a/drivers/net/wireless/ath5k/base.h
+++ b/drivers/net/wireless/ath5k/base.h
@@ -56,7 +56,6 @@
struct ath5k_buf {
struct list_head list;
- unsigned int flags; /* rx descriptor flags */
struct ath5k_desc *desc; /* virtual addr of desc */
dma_addr_t daddr; /* physical addr of desc */
struct sk_buff *skb; /* skbuff for buf */
diff --git a/drivers/net/wireless/ath5k/dma.c b/drivers/net/wireless/ath5k/dma.c
index b65b4fe..941b511 100644
--- a/drivers/net/wireless/ath5k/dma.c
+++ b/drivers/net/wireless/ath5k/dma.c
@@ -80,8 +80,6 @@ int ath5k_hw_stop_rx_dma(struct ath5k_hw *ah)
* ath5k_hw_get_rxdp - Get RX Descriptor's address
*
* @ah: The &struct ath5k_hw
- *
- * XXX: Is RXDP read and clear ?
*/
u32 ath5k_hw_get_rxdp(struct ath5k_hw *ah)
{
--
1.6.0.6
--
Bob Copeland %% www.bobcopeland.com
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