}
+static void storvsc_change_target_cpu(struct vmbus_channel *channel, u32 old,
+ u32 new)
+{
+ struct storvsc_device *stor_device;
+ struct vmbus_channel *cur_chn;
+ bool old_is_alloced = false;
+ struct hv_device *device;
+ unsigned long flags;
+ int cpu;
+
+ device = channel->primary_channel ?
+ channel->primary_channel->device_obj
+ : channel->device_obj;
+ stor_device = get_out_stor_device(device);
+ if (!stor_device)
+ return;
+
+ /* See storvsc_do_io() -> get_og_chn(). */
+ spin_lock_irqsave(&device->channel->lock, flags);
+
+ /*
+ * Determines if the storvsc device has other channels assigned to
+ * the "old" CPU to update the alloced_cpus mask and the stor_chns
+ * array.
+ */
+ if (device->channel != channel && device->channel->target_cpu == old) {
+ cur_chn = device->channel;
+ old_is_alloced = true;
+ goto old_is_alloced;
+ }
+ list_for_each_entry(cur_chn, &device->channel->sc_list, sc_list) {
+ if (cur_chn == channel)
+ continue;
+ if (cur_chn->target_cpu == old) {
+ old_is_alloced = true;
+ goto old_is_alloced;
+ }
+ }
+
+old_is_alloced:
+ if (old_is_alloced)
+ WRITE_ONCE(stor_device->stor_chns[old], cur_chn);
+ else
+ cpumask_clear_cpu(old, &stor_device->alloced_cpus);
+
+ /* "Flush" the stor_chns array. */
+ for_each_possible_cpu(cpu) {
+ if (stor_device->stor_chns[cpu] && !cpumask_test_cpu(
+ cpu, &stor_device->alloced_cpus))
+ WRITE_ONCE(stor_device->stor_chns[cpu], NULL);
+ }
+
+ WRITE_ONCE(stor_device->stor_chns[new], channel);
+ cpumask_set_cpu(new, &stor_device->alloced_cpus);
+
+ spin_unlock_irqrestore(&device->channel->lock, flags);
+}
+
static void handle_sc_creation(struct vmbus_channel *new_sc)
{
struct hv_device *device = new_sc->primary_channel->device_obj;
return;
}
+ new_sc->change_target_cpu_callback = storvsc_change_target_cpu;
+
/* Add the sub-channel to the array of available channels. */
stor_device->stor_chns[new_sc->target_cpu] = new_sc;
cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
if (stor_device->stor_chns == NULL)
return -ENOMEM;
+ device->channel->change_target_cpu_callback = storvsc_change_target_cpu;
+
stor_device->stor_chns[device->channel->target_cpu] = device->channel;
cpumask_set_cpu(device->channel->target_cpu,
&stor_device->alloced_cpus);
const struct cpumask *node_mask;
int num_channels, tgt_cpu;
- if (stor_device->num_sc == 0)
+ if (stor_device->num_sc == 0) {
+ stor_device->stor_chns[q_num] = stor_device->device->channel;
return stor_device->device->channel;
+ }
/*
* Our channel array is sparsley populated and we
* The strategy is simple:
* I. Ensure NUMA locality
* II. Distribute evenly (best effort)
- * III. Mapping is persistent.
*/
node_mask = cpumask_of_node(cpu_to_node(q_num));
if (cpumask_test_cpu(tgt_cpu, node_mask))
num_channels++;
}
- if (num_channels == 0)
+ if (num_channels == 0) {
+ stor_device->stor_chns[q_num] = stor_device->device->channel;
return stor_device->device->channel;
+ }
hash_qnum = q_num;
while (hash_qnum >= num_channels)
struct storvsc_device *stor_device;
struct vstor_packet *vstor_packet;
struct vmbus_channel *outgoing_channel, *channel;
+ unsigned long flags;
int ret = 0;
const struct cpumask *node_mask;
int tgt_cpu;
request->device = device;
/*
- * Select an an appropriate channel to send the request out.
+ * Select an appropriate channel to send the request out.
*/
- if (stor_device->stor_chns[q_num] != NULL) {
- outgoing_channel = stor_device->stor_chns[q_num];
+ /* See storvsc_change_target_cpu(). */
+ outgoing_channel = READ_ONCE(stor_device->stor_chns[q_num]);
+ if (outgoing_channel != NULL) {
if (outgoing_channel->target_cpu == q_num) {
/*
* Ideally, we want to pick a different channel if
continue;
if (tgt_cpu == q_num)
continue;
- channel = stor_device->stor_chns[tgt_cpu];
+ channel = READ_ONCE(
+ stor_device->stor_chns[tgt_cpu]);
+ if (channel == NULL)
+ continue;
if (hv_get_avail_to_write_percent(
&channel->outbound)
> ring_avail_percent_lowater) {
for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
if (cpumask_test_cpu(tgt_cpu, node_mask))
continue;
- channel = stor_device->stor_chns[tgt_cpu];
+ channel = READ_ONCE(
+ stor_device->stor_chns[tgt_cpu]);
+ if (channel == NULL)
+ continue;
if (hv_get_avail_to_write_percent(
&channel->outbound)
> ring_avail_percent_lowater) {
}
}
} else {
+ spin_lock_irqsave(&device->channel->lock, flags);
+ outgoing_channel = stor_device->stor_chns[q_num];
+ if (outgoing_channel != NULL) {
+ spin_unlock_irqrestore(&device->channel->lock, flags);
+ goto found_channel;
+ }
outgoing_channel = get_og_chn(stor_device, q_num);
+ spin_unlock_irqrestore(&device->channel->lock, flags);
}
found_channel: