[PATCH] usb: gadget: rndis: don't use dev_get_stats()
From: Michal Nazarewicz
Date: Mon Sep 20 2010 - 14:21:26 EST
This commit removes the call to dev_get_stats() from the
gen_ndis_query_resp() function. Since spin_lock_bh() was
added to dev_txq_stats_fold() the call started causing
warnings. This is because gen_ndis_query_resp() can be
(indirectly) called from rndis_command_complete() which is
called with interrupts disabled.
While at it, this commit also changes the
gen_ndis_query_resp() function so that "net" local variable is
used instead of "rndis_per_dev_params[configNr].dev" in all
places this is referenced.
Signed-off-by: Michal Nazarewicz <m.nazarewicz@xxxxxxxxxxx>
---
drivers/usb/gadget/rndis.c | 50 +++++++++++++++++++------------------------
1 files changed, 22 insertions(+), 28 deletions(-)
Without this patch, I got the following warning when RNDIS
configuration is chosen:
> WARNING: at kernel/softirq.c:143 local_bh_enable_ip+0x44/0xc0()
[...]
> [<c0049024>] (local_bh_enable_ip+0x44/0xc0) from [<c025ef18>] (dev_txq_stats_fold+0xac/0x108)
> [<c025ef18>] (dev_txq_stats_fold+0xac/0x108) from [<c025f018>] (dev_get_stats+0xa4/0xac)
> [<c025f018>] (dev_get_stats+0xa4/0xac) from [<c01f72bc>] (gen_ndis_query_resp+0x4c/0x43c)
> [<c01f72bc>] (gen_ndis_query_resp+0x4c/0x43c) from [<c01f784c>] (rndis_msg_parser+0x1a0/0x32c)
> [<c01f784c>] (rndis_msg_parser+0x1a0/0x32c) from [<c01f79f8>] (rndis_command_complete+0x20/0x4c)
> [<c01f79f8>] (rndis_command_complete+0x20/0x4c) from [<c01f3278>] (done+0x5c/0x70)
> [<c01f3278>] (done+0x5c/0x70) from [<c01f3c60>] (complete_tx+0xf0/0x1a8)
> [<c01f3c60>] (complete_tx+0xf0/0x1a8) from [<c01f3d8c>] (process_ep_in_intr+0x74/0x14c)
> [<c01f3d8c>] (process_ep_in_intr+0x74/0x14c) from [<c01f470c>] (s3c_udc_irq+0x2c8/0x3f4)
> [<c01f470c>] (s3c_udc_irq+0x2c8/0x3f4) from [<c006dfd0>] (handle_IRQ_event+0x24/0xe4)
> [<c006dfd0>] (handle_IRQ_event+0x24/0xe4) from [<c006fe40>] (handle_level_irq+0xb0/0x12c)
> [<c006fe40>] (handle_level_irq+0xb0/0x12c) from [<c0027074>] (asm_do_IRQ+0x74/0x98)
> [<c0027074>] (asm_do_IRQ+0x74/0x98) from [<c0027ca4>] (__irq_usr+0x44/0xc0)
After some investigation I found out that recently introduced commit
bd27290a593f80cb99e95287cb29c72c0d57608b causes this.
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 1c002c7..9de75cd 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -5282,15 +5282,17 @@ void netdev_run_todo(void)
> void dev_txq_stats_fold(const struct net_device *dev,
> struct rtnl_link_stats64 *stats)
> {
> - unsigned long tx_bytes = 0, tx_packets = 0, tx_dropped = 0;
> + u64 tx_bytes = 0, tx_packets = 0, tx_dropped = 0;
> unsigned int i;
> struct netdev_queue *txq;
>
> for (i = 0; i < dev->num_tx_queues; i++) {
> txq = netdev_get_tx_queue(dev, i);
> + spin_lock_bh(&txq->_xmit_lock);
> tx_bytes += txq->tx_bytes;
> tx_packets += txq->tx_packets;
> tx_dropped += txq->tx_dropped;
> + spin_unlock_bh(&txq->_xmit_lock);
> }
> if (tx_bytes || tx_packets || tx_dropped) {
> stats->tx_bytes = tx_bytes;
David Miller didn't agree to change spin_lock_bh() to
spin_lock_irqsave() so I'm trying to fix the issue by changing
rndis.c.
At this point, I'm not entirely sure whether replacing dev_get_stats()
with simple access to net->stats doesn't break something and I'm not
really sure how to test that either (g_ether works when connected to
Windows host).
The other solution would be to change rndis_command_complete() so that
a tasklet is used.
If everyone is happy with this change, I think it's good idea
to get it pulled before 2.6.36.
Also, David (Brownel), can rndis_per_dev_params[configNr].dev
be ever NULL? The line dev_get_stats() assumed it's never
NULL but some other parts of the code checked the value.
I left the checking just to be safe but maybe it can be
dropped?
diff --git a/drivers/usb/gadget/rndis.c b/drivers/usb/gadget/rndis.c
index 972d5dd..ea597cc 100644
--- a/drivers/usb/gadget/rndis.c
+++ b/drivers/usb/gadget/rndis.c
@@ -171,8 +171,6 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
int i, count;
rndis_query_cmplt_type *resp;
struct net_device *net;
- struct rtnl_link_stats64 temp;
- const struct rtnl_link_stats64 *stats;
if (!r) return -ENOMEM;
resp = (rndis_query_cmplt_type *) r->buf;
@@ -195,7 +193,6 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
resp->InformationBufferOffset = cpu_to_le32 (16);
net = rndis_per_dev_params[configNr].dev;
- stats = dev_get_stats(net, &temp);
switch (OID) {
@@ -242,9 +239,8 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
/* mandatory */
case OID_GEN_MAXIMUM_FRAME_SIZE:
pr_debug("%s: OID_GEN_MAXIMUM_FRAME_SIZE\n", __func__);
- if (rndis_per_dev_params [configNr].dev) {
- *outbuf = cpu_to_le32 (
- rndis_per_dev_params [configNr].dev->mtu);
+ if (net) {
+ *outbuf = cpu_to_le32(net->mtu);
retval = 0;
}
break;
@@ -265,9 +261,8 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
/* mandatory */
case OID_GEN_TRANSMIT_BLOCK_SIZE:
pr_debug("%s: OID_GEN_TRANSMIT_BLOCK_SIZE\n", __func__);
- if (rndis_per_dev_params [configNr].dev) {
- *outbuf = cpu_to_le32 (
- rndis_per_dev_params [configNr].dev->mtu);
+ if (net) {
+ *outbuf = cpu_to_le32(net->mtu);
retval = 0;
}
break;
@@ -275,9 +270,8 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
/* mandatory */
case OID_GEN_RECEIVE_BLOCK_SIZE:
pr_debug("%s: OID_GEN_RECEIVE_BLOCK_SIZE\n", __func__);
- if (rndis_per_dev_params [configNr].dev) {
- *outbuf = cpu_to_le32 (
- rndis_per_dev_params [configNr].dev->mtu);
+ if (net) {
+ *outbuf = cpu_to_le32(net->mtu);
retval = 0;
}
break;
@@ -357,9 +351,9 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
case OID_GEN_XMIT_OK:
if (rndis_debug > 1)
pr_debug("%s: OID_GEN_XMIT_OK\n", __func__);
- if (stats) {
- *outbuf = cpu_to_le32(stats->tx_packets
- - stats->tx_errors - stats->tx_dropped);
+ if (net) {
+ *outbuf = cpu_to_le32(net->stats.tx_packets
+ - net->stats.tx_errors - net->stats.tx_dropped);
retval = 0;
}
break;
@@ -368,9 +362,9 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
case OID_GEN_RCV_OK:
if (rndis_debug > 1)
pr_debug("%s: OID_GEN_RCV_OK\n", __func__);
- if (stats) {
- *outbuf = cpu_to_le32(stats->rx_packets
- - stats->rx_errors - stats->rx_dropped);
+ if (net) {
+ *outbuf = cpu_to_le32(net->stats.rx_packets
+ - net->stats.rx_errors - net->stats.rx_dropped);
retval = 0;
}
break;
@@ -379,8 +373,8 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
case OID_GEN_XMIT_ERROR:
if (rndis_debug > 1)
pr_debug("%s: OID_GEN_XMIT_ERROR\n", __func__);
- if (stats) {
- *outbuf = cpu_to_le32(stats->tx_errors);
+ if (net) {
+ *outbuf = cpu_to_le32(net->stats.tx_errors);
retval = 0;
}
break;
@@ -389,8 +383,8 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
case OID_GEN_RCV_ERROR:
if (rndis_debug > 1)
pr_debug("%s: OID_GEN_RCV_ERROR\n", __func__);
- if (stats) {
- *outbuf = cpu_to_le32(stats->rx_errors);
+ if (net) {
+ *outbuf = cpu_to_le32(net->stats.rx_errors);
retval = 0;
}
break;
@@ -398,8 +392,8 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
/* mandatory */
case OID_GEN_RCV_NO_BUFFER:
pr_debug("%s: OID_GEN_RCV_NO_BUFFER\n", __func__);
- if (stats) {
- *outbuf = cpu_to_le32(stats->rx_dropped);
+ if (net) {
+ *outbuf = cpu_to_le32(net->stats.rx_dropped);
retval = 0;
}
break;
@@ -409,7 +403,7 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
/* mandatory */
case OID_802_3_PERMANENT_ADDRESS:
pr_debug("%s: OID_802_3_PERMANENT_ADDRESS\n", __func__);
- if (rndis_per_dev_params [configNr].dev) {
+ if (net) {
length = ETH_ALEN;
memcpy (outbuf,
rndis_per_dev_params [configNr].host_mac,
@@ -421,7 +415,7 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
/* mandatory */
case OID_802_3_CURRENT_ADDRESS:
pr_debug("%s: OID_802_3_CURRENT_ADDRESS\n", __func__);
- if (rndis_per_dev_params [configNr].dev) {
+ if (net) {
length = ETH_ALEN;
memcpy (outbuf,
rndis_per_dev_params [configNr].host_mac,
@@ -457,8 +451,8 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
/* mandatory */
case OID_802_3_RCV_ERROR_ALIGNMENT:
pr_debug("%s: OID_802_3_RCV_ERROR_ALIGNMENT\n", __func__);
- if (stats) {
- *outbuf = cpu_to_le32(stats->rx_frame_errors);
+ if (net) {
+ *outbuf = cpu_to_le32(net->stats.rx_frame_errors);
retval = 0;
}
break;
--
1.7.1
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