Re: [PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy()
Thanks for giving feedback. On 21 August 2014 23:43, Michał Mirosław wrote: > This has implicit: if (!skb) BUG(); There should probably be a return > or continue inside the if (!skb). Fixed, see v6 update (broken out to separate patch) which now includes increment to RX head counter > dma_sync_single_for_device() is not needed here as CPU does not and > should not write to the DMA_FROM_DEVICE mapping. Fixed, this was also broken out, dma_sync_single_for_device() moved to TX path. Maybe someone can verify this is the correct thing to do. Regards, Jonas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy()
Thanks for giving feedback. On 21 August 2014 23:43, Michał Mirosław mir...@gmail.com wrote: This has implicit: if (!skb) BUG(); There should probably be a return or continue inside the if (!skb). Fixed, see v6 update (broken out to separate patch) which now includes increment to RX head counter dma_sync_single_for_device() is not needed here as CPU does not and should not write to the DMA_FROM_DEVICE mapping. Fixed, this was also broken out, dma_sync_single_for_device() moved to TX path. Maybe someone can verify this is the correct thing to do. Regards, Jonas -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy()
2014-08-19 16:49 GMT+02:00 Jonas Jensen :
[...]
> diff --git a/drivers/net/ethernet/moxa/moxart_ether.c
> b/drivers/net/ethernet/moxa/moxart_ether.c
> index aa45607..17c9f0e 100644
> --- a/drivers/net/ethernet/moxa/moxart_ether.c
> +++ b/drivers/net/ethernet/moxa/moxart_ether.c
> @@ -226,14 +226,21 @@ static int moxart_rx_poll(struct napi_struct *napi, int
> budget)
> if (len > RX_BUF_SIZE)
> len = RX_BUF_SIZE;
>
> - skb = build_skb(priv->rx_buf[rx_head], priv->rx_buf_size);
> + dma_sync_single_for_cpu(>dev,
> + priv->rx_mapping[rx_head],
> + priv->rx_buf_size, DMA_FROM_DEVICE);
> + skb = netdev_alloc_skb_ip_align(ndev, len);
> if (unlikely(!skb)) {
> - net_dbg_ratelimited("build_skb failed\n");
> + net_dbg_ratelimited("netdev_alloc_skb_ip_align
> failed\n");
> priv->stats.rx_dropped++;
> priv->stats.rx_errors++;
> }
> -
> + memcpy(skb->data, priv->rx_buf[rx_head], len);
This has implicit: if (!skb) BUG(); There should probably be a return
or continue inside the if (!skb).
> skb_put(skb, len);
> + dma_sync_single_for_device(>dev,
> + priv->rx_mapping[rx_head],
> + priv->rx_buf_size,
> DMA_FROM_DEVICE);
> +
dma_sync_single_for_device() is not needed here as CPU does not and
should not write to the DMA_FROM_DEVICE mapping.
> skb->protocol = eth_type_trans(skb, ndev);
> napi_gro_receive(>napi, skb);
> rx++;
Best Regards,
Michał Mirosław
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Re: [PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy()
2014-08-19 16:49 GMT+02:00 Jonas Jensen jonas.jen...@gmail.com:
[...]
diff --git a/drivers/net/ethernet/moxa/moxart_ether.c
b/drivers/net/ethernet/moxa/moxart_ether.c
index aa45607..17c9f0e 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -226,14 +226,21 @@ static int moxart_rx_poll(struct napi_struct *napi, int
budget)
if (len RX_BUF_SIZE)
len = RX_BUF_SIZE;
- skb = build_skb(priv-rx_buf[rx_head], priv-rx_buf_size);
+ dma_sync_single_for_cpu(ndev-dev,
+ priv-rx_mapping[rx_head],
+ priv-rx_buf_size, DMA_FROM_DEVICE);
+ skb = netdev_alloc_skb_ip_align(ndev, len);
if (unlikely(!skb)) {
- net_dbg_ratelimited(build_skb failed\n);
+ net_dbg_ratelimited(netdev_alloc_skb_ip_align
failed\n);
priv-stats.rx_dropped++;
priv-stats.rx_errors++;
}
-
+ memcpy(skb-data, priv-rx_buf[rx_head], len);
This has implicit: if (!skb) BUG(); There should probably be a return
or continue inside the if (!skb).
skb_put(skb, len);
+ dma_sync_single_for_device(ndev-dev,
+ priv-rx_mapping[rx_head],
+ priv-rx_buf_size,
DMA_FROM_DEVICE);
+
dma_sync_single_for_device() is not needed here as CPU does not and
should not write to the DMA_FROM_DEVICE mapping.
skb-protocol = eth_type_trans(skb, ndev);
napi_gro_receive(priv-napi, skb);
rx++;
Best Regards,
Michał Mirosław
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Re: [PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy()
On 19 August 2014 20:31, Eric Dumazet wrote: > Instead of : > > priv->rx_buf_size = RX_BUF_SIZE + > SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); > > I think rx_buf_size can now be RX_BUF_SIZE You're right, that's now a remnant, see update in v5. > Another point is that priv->stats seems not needed, as ndev->stats could > be used instead (and remove moxart_mac_get_stats()) I will fix that. I can add it to patches adding support for ethtool / stats and PHY. I think I'm supposed to post those closer to the merge window, which would keep this set about bug fixes only. Regards, Jonas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy()
On 19 August 2014 20:31, Eric Dumazet eric.duma...@gmail.com wrote: Instead of : priv-rx_buf_size = RX_BUF_SIZE + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); I think rx_buf_size can now be RX_BUF_SIZE You're right, that's now a remnant, see update in v5. Another point is that priv-stats seems not needed, as ndev-stats could be used instead (and remove moxart_mac_get_stats()) I will fix that. I can add it to patches adding support for ethtool / stats and PHY. I think I'm supposed to post those closer to the merge window, which would keep this set about bug fixes only. Regards, Jonas -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy()
On Tue, 2014-08-19 at 16:49 +0200, Jonas Jensen wrote: > build_skb() is used to make skbs out of existing RX ring memory > which is bad because the RX ring is allocated only once, on probe. > Memory corruption occur because said memory is reclaimed, i.e. > __kfree_skb() (and eventually put_page()). > > Replace build_skb() with netdev_alloc_skb_ip_align() and use memcpy(). > Also, synchronize DMA memory before passing skb to napi_gro_receive(). > > Addresses https://bugzilla.kernel.org/show_bug.cgi?id=69041 Wow, this driver was really buggy. Patch is not complete. Instead of : priv->rx_buf_size = RX_BUF_SIZE + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); I think rx_buf_size can now be RX_BUF_SIZE Another point is that priv->stats seems not needed, as ndev->stats could be used instead (and remove moxart_mac_get_stats()) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy()
build_skb() is used to make skbs out of existing RX ring memory
which is bad because the RX ring is allocated only once, on probe.
Memory corruption occur because said memory is reclaimed, i.e.
__kfree_skb() (and eventually put_page()).
Replace build_skb() with netdev_alloc_skb_ip_align() and use memcpy().
Also, synchronize DMA memory before passing skb to napi_gro_receive().
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=69041
Signed-off-by: Jonas Jensen
---
Notes:
The original motivation was to avoid memcpy(), since the memory is
already allocated, why make a copy.
Maybe the copy can be avoided updating RX ring descriptor addresses;
new memory must be allocated just the same, the only difference that
the controller could write directly to it.
This fixes errors due to memory corruption, such as the following,
seen on wget download (or ncftp):
"read error: Bad address"
On receiving error, wget exits without resuming (busybox default).
Changes since v3:
1. commit message reworded
Applies to next-20140818
drivers/net/ethernet/moxa/moxart_ether.c | 13 ++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/moxa/moxart_ether.c
b/drivers/net/ethernet/moxa/moxart_ether.c
index aa45607..17c9f0e 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -226,14 +226,21 @@ static int moxart_rx_poll(struct napi_struct *napi, int
budget)
if (len > RX_BUF_SIZE)
len = RX_BUF_SIZE;
- skb = build_skb(priv->rx_buf[rx_head], priv->rx_buf_size);
+ dma_sync_single_for_cpu(>dev,
+ priv->rx_mapping[rx_head],
+ priv->rx_buf_size, DMA_FROM_DEVICE);
+ skb = netdev_alloc_skb_ip_align(ndev, len);
if (unlikely(!skb)) {
- net_dbg_ratelimited("build_skb failed\n");
+ net_dbg_ratelimited("netdev_alloc_skb_ip_align
failed\n");
priv->stats.rx_dropped++;
priv->stats.rx_errors++;
}
-
+ memcpy(skb->data, priv->rx_buf[rx_head], len);
skb_put(skb, len);
+ dma_sync_single_for_device(>dev,
+ priv->rx_mapping[rx_head],
+ priv->rx_buf_size, DMA_FROM_DEVICE);
+
skb->protocol = eth_type_trans(skb, ndev);
napi_gro_receive(>napi, skb);
rx++;
--
1.8.2.1
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[PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy()
build_skb() is used to make skbs out of existing RX ring memory
which is bad because the RX ring is allocated only once, on probe.
Memory corruption occur because said memory is reclaimed, i.e.
__kfree_skb() (and eventually put_page()).
Replace build_skb() with netdev_alloc_skb_ip_align() and use memcpy().
Also, synchronize DMA memory before passing skb to napi_gro_receive().
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=69041
Signed-off-by: Jonas Jensen jonas.jen...@gmail.com
---
Notes:
The original motivation was to avoid memcpy(), since the memory is
already allocated, why make a copy.
Maybe the copy can be avoided updating RX ring descriptor addresses;
new memory must be allocated just the same, the only difference that
the controller could write directly to it.
This fixes errors due to memory corruption, such as the following,
seen on wget download (or ncftp):
read error: Bad address
On receiving error, wget exits without resuming (busybox default).
Changes since v3:
1. commit message reworded
Applies to next-20140818
drivers/net/ethernet/moxa/moxart_ether.c | 13 ++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/moxa/moxart_ether.c
b/drivers/net/ethernet/moxa/moxart_ether.c
index aa45607..17c9f0e 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -226,14 +226,21 @@ static int moxart_rx_poll(struct napi_struct *napi, int
budget)
if (len RX_BUF_SIZE)
len = RX_BUF_SIZE;
- skb = build_skb(priv-rx_buf[rx_head], priv-rx_buf_size);
+ dma_sync_single_for_cpu(ndev-dev,
+ priv-rx_mapping[rx_head],
+ priv-rx_buf_size, DMA_FROM_DEVICE);
+ skb = netdev_alloc_skb_ip_align(ndev, len);
if (unlikely(!skb)) {
- net_dbg_ratelimited(build_skb failed\n);
+ net_dbg_ratelimited(netdev_alloc_skb_ip_align
failed\n);
priv-stats.rx_dropped++;
priv-stats.rx_errors++;
}
-
+ memcpy(skb-data, priv-rx_buf[rx_head], len);
skb_put(skb, len);
+ dma_sync_single_for_device(ndev-dev,
+ priv-rx_mapping[rx_head],
+ priv-rx_buf_size, DMA_FROM_DEVICE);
+
skb-protocol = eth_type_trans(skb, ndev);
napi_gro_receive(priv-napi, skb);
rx++;
--
1.8.2.1
--
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v4 2/2] net: moxa: replace build_skb() with netdev_alloc_skb_ip_align() / memcpy()
On Tue, 2014-08-19 at 16:49 +0200, Jonas Jensen wrote: build_skb() is used to make skbs out of existing RX ring memory which is bad because the RX ring is allocated only once, on probe. Memory corruption occur because said memory is reclaimed, i.e. __kfree_skb() (and eventually put_page()). Replace build_skb() with netdev_alloc_skb_ip_align() and use memcpy(). Also, synchronize DMA memory before passing skb to napi_gro_receive(). Addresses https://bugzilla.kernel.org/show_bug.cgi?id=69041 Wow, this driver was really buggy. Patch is not complete. Instead of : priv-rx_buf_size = RX_BUF_SIZE + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); I think rx_buf_size can now be RX_BUF_SIZE Another point is that priv-stats seems not needed, as ndev-stats could be used instead (and remove moxart_mac_get_stats()) -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
