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| author | Andrea Merello <andrea.merello@gmail.com> | 2017-07-08 10:11:11 +0200 |
|---|---|---|
| committer | Mathias Kresin <dev@kresin.me> | 2017-07-20 19:10:29 +0200 |
| commit | b81c04382b5ddea0164993c2af0df7270bb95ee4 (patch) | |
| tree | 0d277e90337a8c8ef304da6e6c93ef0c376510aa /target/linux | |
| parent | 34c01e68b5d6b06ce3794ef0e2b06e81ec3ce8ca (diff) | |
| download | mtk-20170518-b81c04382b5ddea0164993c2af0df7270bb95ee4.zip mtk-20170518-b81c04382b5ddea0164993c2af0df7270bb95ee4.tar.gz mtk-20170518-b81c04382b5ddea0164993c2af0df7270bb95ee4.tar.bz2 | |
lantiq: fix sleep with spinlock held in xrx200 network driver
In the xrx200_close() function we call napi_disable(), that could
sleep, with priv->hw->chan[i].lock held. This could lead to deadlock
and causes the kernel to complain.
Look at the code I couldn't convince myself about why we
need to protect that specific code part with the lock. IMHO there
seems no reason to protect the refcount variables, because AFAIK
ndo_close() and ndo_open() callbacks are already called with a
semaphore held. Neither I could figure out why napi_disable() have to
be called with that lock held. The only remaining code part for
which I could guess the lock is useful for is ltq_dma_close()
function call.
This patch reduces the lock to the said function call, avoiding the
sleep-with-spinlock-held situation
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
[fold into 0025-NET-MIPS-lantiq-adds-xrx200-net.patch, backport to
kernel 4.4]
Signed-off-by: Mathias Kresin <dev@kresin.me>
Diffstat (limited to 'target/linux')
| -rw-r--r-- | target/linux/lantiq/patches-4.4/0025-NET-MIPS-lantiq-adds-xrx200-net.patch | 7 | ||||
| -rw-r--r-- | target/linux/lantiq/patches-4.9/0025-NET-MIPS-lantiq-adds-xrx200-net.patch | 7 |
2 files changed, 8 insertions, 6 deletions
diff --git a/target/linux/lantiq/patches-4.4/0025-NET-MIPS-lantiq-adds-xrx200-net.patch b/target/linux/lantiq/patches-4.4/0025-NET-MIPS-lantiq-adds-xrx200-net.patch index 1550f26..ccb0733 100644 --- a/target/linux/lantiq/patches-4.4/0025-NET-MIPS-lantiq-adds-xrx200-net.patch +++ b/target/linux/lantiq/patches-4.4/0025-NET-MIPS-lantiq-adds-xrx200-net.patch @@ -209,7 +209,7 @@ Subject: [PATCH 25/36] NET: MIPS: lantiq: adds xrx200-net +}; --- /dev/null +++ b/drivers/net/ethernet/lantiq_xrx200.c -@@ -0,0 +1,1852 @@ +@@ -0,0 +1,1853 @@ +/* + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published @@ -1110,14 +1110,15 @@ Subject: [PATCH 25/36] NET: MIPS: lantiq: adds xrx200-net + for (i = 0; i < XRX200_MAX_DMA; i++) { + if (!priv->hw->chan[i].dma.irq) + continue; -+ spin_lock_bh(&priv->hw->chan[i].lock); ++ + priv->hw->chan[i].refcount--; + if (!priv->hw->chan[i].refcount) { + if (XRX200_DMA_IS_RX(i)) + napi_disable(&priv->hw->chan[i].napi); ++ spin_lock_bh(&priv->hw->chan[i].lock); + ltq_dma_close(&priv->hw->chan[XRX200_DMA_RX].dma); ++ spin_unlock_bh(&priv->hw->chan[i].lock); + } -+ spin_unlock_bh(&priv->hw->chan[i].lock); + } + + return 0; diff --git a/target/linux/lantiq/patches-4.9/0025-NET-MIPS-lantiq-adds-xrx200-net.patch b/target/linux/lantiq/patches-4.9/0025-NET-MIPS-lantiq-adds-xrx200-net.patch index 80bcea0..8711764 100644 --- a/target/linux/lantiq/patches-4.9/0025-NET-MIPS-lantiq-adds-xrx200-net.patch +++ b/target/linux/lantiq/patches-4.9/0025-NET-MIPS-lantiq-adds-xrx200-net.patch @@ -209,7 +209,7 @@ Subject: [PATCH 25/36] NET: MIPS: lantiq: adds xrx200-net +}; --- /dev/null +++ b/drivers/net/ethernet/lantiq_xrx200.c -@@ -0,0 +1,1851 @@ +@@ -0,0 +1,1852 @@ +/* + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published @@ -1110,14 +1110,15 @@ Subject: [PATCH 25/36] NET: MIPS: lantiq: adds xrx200-net + for (i = 0; i < XRX200_MAX_DMA; i++) { + if (!priv->hw->chan[i].dma.irq) + continue; -+ spin_lock_bh(&priv->hw->chan[i].lock); ++ + priv->hw->chan[i].refcount--; + if (!priv->hw->chan[i].refcount) { + if (XRX200_DMA_IS_RX(i)) + napi_disable(&priv->hw->chan[i].napi); ++ spin_lock_bh(&priv->hw->chan[i].lock); + ltq_dma_close(&priv->hw->chan[XRX200_DMA_RX].dma); ++ spin_unlock_bh(&priv->hw->chan[i].lock); + } -+ spin_unlock_bh(&priv->hw->chan[i].lock); + } + + return 0; |