diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2022-02-16 20:50:46 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-02-23 19:04:27 +0300 |
| commit | 167053f8dd0ed60287858448696b4784d7e1d899 (patch) | |
| tree | 4cc4c7db171bf68db80a02f856762690fb7cb5a9 /net/core | |
| parent | 6ce71687d4f4105350ddbc92aa12e6bc9839f103 (diff) | |
| download | linux-167053f8dd0ed60287858448696b4784d7e1d899.tar.xz | |
net: Correct wrong BH disable in hard-interrupt.
I missed the obvious case where netif_ix() is invoked from hard-IRQ
context.
Disabling bottom halves is only needed in process context. This ensures
that the code remains on the current CPU and that the soft-interrupts
are processed at local_bh_enable() time.
In hard- and soft-interrupt context this is already the case and the
soft-interrupts will be processed once the context is left (at irq-exit
time).
Disable bottom halves if neither hard-interrupts nor soft-interrupts are
disabled. Update the kernel-doc, mention that interrupts must be enabled
if invoked from process context.
Fixes: baebdf48c3600 ("net: dev: Makes sure netif_rx() can be invoked in any context.")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/Yg05duINKBqvnxUc@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dev.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index a1190291c48e..2d6771075720 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4860,7 +4860,9 @@ EXPORT_SYMBOL(__netif_rx); * congestion control or by the protocol layers. * The network buffer is passed via the backlog NAPI device. Modern NIC * driver should use NAPI and GRO. - * This function can used from any context. + * This function can used from interrupt and from process context. The + * caller from process context must not disable interrupts before invoking + * this function. * * return values: * NET_RX_SUCCESS (no congestion) @@ -4869,13 +4871,16 @@ EXPORT_SYMBOL(__netif_rx); */ int netif_rx(struct sk_buff *skb) { + bool need_bh_off = !(hardirq_count() | softirq_count()); int ret; - local_bh_disable(); + if (need_bh_off) + local_bh_disable(); trace_netif_rx_entry(skb); ret = netif_rx_internal(skb); trace_netif_rx_exit(ret); - local_bh_enable(); + if (need_bh_off) + local_bh_enable(); return ret; } EXPORT_SYMBOL(netif_rx); |