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authorQuintin Pitts <geek4linux@gmail.com>2010-04-09 21:37:38 +0200
committerJohn W. Linville <linville@tuxdriver.com>2010-04-12 15:22:10 -0400
commit5988f385b4cffa9ca72c5be0188e5f4c9ef46d82 (patch)
tree2c79481788945047c97b4ffe54a3c49362c3789a
parentb1f90866fb3a329b1c4ebfff93ae9c110943e50a (diff)
p54pci: prevent stuck rx-ring on slow system
This patch fixes an old problem, which - under certain circumstances - could cause the device to become unresponsive. most of p54pci's rx-ring management is implemented in just two distinct standalone functions. p54p_check_rx_ring takes care of processing incoming data, while p54p_refill_rx_ring tries to replenish all depleted communication buffers. This has always worked fine on my fast machine, but now I know there is a hidden race... The most likely candidate here is ring_control->device_idx. Quintin Pitts had already analyzed the culprit and posted a patch back in Oct 2009. But sadly, no one's picked up on this. ( https://patchwork.kernel.org/patch/53079/ [2 & 3] ). This patch does the same way, except that it also prioritize rx data processing, simply because tx routines *can* wait. Reported-by: Sean Young <sean@mess.org> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=11386 Reported-by: Quintin Pitts <geek4linux@gmail.com> Signed-off-by: Quintin Pitts <geek4linux@gmail.com> Signed-off-by: Christian Lamparter <chunkeey@googlemail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
-rw-r--r--drivers/net/wireless/p54/p54pci.c26
1 files changed, 13 insertions, 13 deletions
diff --git a/drivers/net/wireless/p54/p54pci.c b/drivers/net/wireless/p54/p54pci.c
index ed4bdffdd63..aa29663bf6c 100644
--- a/drivers/net/wireless/p54/p54pci.c
+++ b/drivers/net/wireless/p54/p54pci.c
@@ -131,7 +131,7 @@ static int p54p_upload_firmware(struct ieee80211_hw *dev)
static void p54p_refill_rx_ring(struct ieee80211_hw *dev,
int ring_index, struct p54p_desc *ring, u32 ring_limit,
- struct sk_buff **rx_buf)
+ struct sk_buff **rx_buf, u32 index)
{
struct p54p_priv *priv = dev->priv;
struct p54p_ring_control *ring_control = priv->ring_control;
@@ -139,7 +139,7 @@ static void p54p_refill_rx_ring(struct ieee80211_hw *dev,
idx = le32_to_cpu(ring_control->host_idx[ring_index]);
limit = idx;
- limit -= le32_to_cpu(ring_control->device_idx[ring_index]);
+ limit -= le32_to_cpu(index);
limit = ring_limit - limit;
i = idx % ring_limit;
@@ -231,7 +231,7 @@ static void p54p_check_rx_ring(struct ieee80211_hw *dev, u32 *index,
i %= ring_limit;
}
- p54p_refill_rx_ring(dev, ring_index, ring, ring_limit, rx_buf);
+ p54p_refill_rx_ring(dev, ring_index, ring, ring_limit, rx_buf, *index);
}
static void p54p_check_tx_ring(struct ieee80211_hw *dev, u32 *index,
@@ -276,14 +276,6 @@ static void p54p_tasklet(unsigned long dev_id)
struct p54p_priv *priv = dev->priv;
struct p54p_ring_control *ring_control = priv->ring_control;
- p54p_check_tx_ring(dev, &priv->tx_idx_mgmt, 3, ring_control->tx_mgmt,
- ARRAY_SIZE(ring_control->tx_mgmt),
- priv->tx_buf_mgmt);
-
- p54p_check_tx_ring(dev, &priv->tx_idx_data, 1, ring_control->tx_data,
- ARRAY_SIZE(ring_control->tx_data),
- priv->tx_buf_data);
-
p54p_check_rx_ring(dev, &priv->rx_idx_mgmt, 2, ring_control->rx_mgmt,
ARRAY_SIZE(ring_control->rx_mgmt), priv->rx_buf_mgmt);
@@ -292,6 +284,14 @@ static void p54p_tasklet(unsigned long dev_id)
wmb();
P54P_WRITE(dev_int, cpu_to_le32(ISL38XX_DEV_INT_UPDATE));
+
+ p54p_check_tx_ring(dev, &priv->tx_idx_mgmt, 3, ring_control->tx_mgmt,
+ ARRAY_SIZE(ring_control->tx_mgmt),
+ priv->tx_buf_mgmt);
+
+ p54p_check_tx_ring(dev, &priv->tx_idx_data, 1, ring_control->tx_data,
+ ARRAY_SIZE(ring_control->tx_data),
+ priv->tx_buf_data);
}
static irqreturn_t p54p_interrupt(int irq, void *dev_id)
@@ -444,10 +444,10 @@ static int p54p_open(struct ieee80211_hw *dev)
priv->rx_idx_mgmt = priv->tx_idx_mgmt = 0;
p54p_refill_rx_ring(dev, 0, priv->ring_control->rx_data,
- ARRAY_SIZE(priv->ring_control->rx_data), priv->rx_buf_data);
+ ARRAY_SIZE(priv->ring_control->rx_data), priv->rx_buf_data, 0);
p54p_refill_rx_ring(dev, 2, priv->ring_control->rx_mgmt,
- ARRAY_SIZE(priv->ring_control->rx_mgmt), priv->rx_buf_mgmt);
+ ARRAY_SIZE(priv->ring_control->rx_mgmt), priv->rx_buf_mgmt, 0);
P54P_WRITE(ring_control_base, cpu_to_le32(priv->ring_control_dma));
P54P_READ(ring_control_base);