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net: ibm: emac: mal: fix NAPI locking

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Since commit 413f0271f3 ("net: protect NAPI enablement with
netdev_lock()"), napi_enable() and napi_disable() take netdev_lock().

mal_register_commac() and mal_unregister_commac() call these helpers
while holding mal->lock with interrupts disabled. In the unregister
path, napi_disable() may also wait for polling to finish, while the poll
completion path takes mal->lock.

Take netdev_lock() before mal->lock, use the locked NAPI helpers, and
drop mal->lock before napi_disable_locked().

Fixes: 413f0271f3 ("net: protect NAPI enablement with netdev_lock()")
Cc: stable@vger.kernel.org
Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260811070813.377573-1-runyu.xiao@seu.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Runyu Xiao 2026-08-11 15:08:13 +08:00 committed by Jakub Kicinski
parent a22054d743
commit 43b0213529
1 changed files with 10 additions and 3 deletions
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13
drivers/net/ethernet/ibm/emac/mal.c
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@ -35,6 +35,7 @@ int mal_register_commac(struct mal_instance *mal, struct mal_commac *commac)
{
unsigned long flags;
netdev_lock(mal->napi.dev);
spin_lock_irqsave(&mal->lock, flags);
MAL_DBG(mal, "reg(%08x, %08x)" NL,
@ -44,18 +45,20 @@ int mal_register_commac(struct mal_instance *mal, struct mal_commac *commac)
if ((mal->tx_chan_mask & commac->tx_chan_mask) ||
(mal->rx_chan_mask & commac->rx_chan_mask)) {
spin_unlock_irqrestore(&mal->lock, flags);
netdev_unlock(mal->napi.dev);
printk(KERN_WARNING "mal%d: COMMAC channels conflict!\n",
mal->index);
return -EBUSY;
}
if (list_empty(&mal->list))
napi_enable(&mal->napi);
napi_enable_locked(&mal->napi);
mal->tx_chan_mask |= commac->tx_chan_mask;
mal->rx_chan_mask |= commac->rx_chan_mask;
list_add(&commac->list, &mal->list);
spin_unlock_irqrestore(&mal->lock, flags);
netdev_unlock(mal->napi.dev);
return 0;
}
@ -64,7 +67,9 @@ void mal_unregister_commac(struct mal_instance *mal,
struct mal_commac *commac)
{
unsigned long flags;
bool disable_napi;
netdev_lock(mal->napi.dev);
spin_lock_irqsave(&mal->lock, flags);
MAL_DBG(mal, "unreg(%08x, %08x)" NL,
@ -73,10 +78,12 @@ void mal_unregister_commac(struct mal_instance *mal,
mal->tx_chan_mask &= ~commac->tx_chan_mask;
mal->rx_chan_mask &= ~commac->rx_chan_mask;
list_del_init(&commac->list);
if (list_empty(&mal->list))
napi_disable(&mal->napi);
disable_napi = list_empty(&mal->list);
spin_unlock_irqrestore(&mal->lock, flags);
if (disable_napi)
napi_disable_locked(&mal->napi);
netdev_unlock(mal->napi.dev);
}
int mal_set_rcbs(struct mal_instance *mal, int channel, unsigned long size)