diff options
Diffstat (limited to 'drivers/hv/vmbus_drv.c')
| -rw-r--r-- | drivers/hv/vmbus_drv.c | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 21a01bca7fcd..0f7dfa507a40 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1202,18 +1202,6 @@ static void vmbus_force_channel_rescinded(struct vmbus_channel *channel) #endif /* CONFIG_PM_SLEEP */ /* - * Direct callback for channels using other deferred processing - */ -static void vmbus_channel_isr(struct vmbus_channel *channel) -{ - void (*callback_fn)(void *); - - callback_fn = READ_ONCE(channel->onchannel_callback); - if (likely(callback_fn != NULL)) - (*callback_fn)(channel->channel_callback_context); -} - -/* * Schedule all channels with events pending */ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) @@ -1243,6 +1231,7 @@ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) return; for_each_set_bit(relid, recv_int_page, maxbits) { + void (*callback_fn)(void *context); struct vmbus_channel *channel; if (!sync_test_and_clear_bit(relid, recv_int_page)) @@ -1268,13 +1257,26 @@ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) if (channel->rescind) goto sched_unlock_rcu; + /* + * Make sure that the ring buffer data structure doesn't get + * freed while we dereference the ring buffer pointer. Test + * for the channel's onchannel_callback being NULL within a + * sched_lock critical section. See also the inline comments + * in vmbus_reset_channel_cb(). + */ + spin_lock(&channel->sched_lock); + + callback_fn = channel->onchannel_callback; + if (unlikely(callback_fn == NULL)) + goto sched_unlock; + trace_vmbus_chan_sched(channel); ++channel->interrupts; switch (channel->callback_mode) { case HV_CALL_ISR: - vmbus_channel_isr(channel); + (*callback_fn)(channel->channel_callback_context); break; case HV_CALL_BATCHED: @@ -1284,6 +1286,8 @@ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) tasklet_schedule(&channel->callback_event); } +sched_unlock: + spin_unlock(&channel->sched_lock); sched_unlock_rcu: rcu_read_unlock(); } |