[v2,1/4] bus/vmbus: fix race in sub channel creation
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Commit Message
When using multiple queues, there was a race with the kernel
in setting up the second channel. This regression is due to a kernel change
which does not allow accessing sysfs files for Hyper-V channels that are not opened.
The fix is simple, just move the logic to detect not ready
sub channels earlier in the existing loop.
Fixes: 831dba47bd36 ("bus/vmbus: add Hyper-V virtual bus support")
Reported-by:Mohammed Gamal <mgamal@redhat.com>
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
---
drivers/bus/vmbus/linux/vmbus_uio.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
Comments
05/12/2018 23:11, Stephen Hemminger:
> When using multiple queues, there was a race with the kernel
> in setting up the second channel. This regression is due to a kernel change
> which does not allow accessing sysfs files for Hyper-V channels that are not opened.
>
> The fix is simple, just move the logic to detect not ready
> sub channels earlier in the existing loop.
>
> Fixes: 831dba47bd36 ("bus/vmbus: add Hyper-V virtual bus support")
> Reported-by:Mohammed Gamal <mgamal@redhat.com>
> Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
+Cc stable@dpdk.org
Series applied, thanks
@@ -357,6 +357,12 @@ int vmbus_uio_get_subchan(struct vmbus_channel *primary,
continue;
}
+ if (!vmbus_isnew_subchannel(primary, relid))
+ continue; /* Already know about you */
+
+ if (!vmbus_uio_ring_present(dev, relid))
+ continue; /* Ring may not be ready yet */
+
snprintf(subchan_path, sizeof(subchan_path), "%s/%lu",
chan_path, relid);
err = vmbus_uio_sysfs_read(subchan_path, "subchannel_id",
@@ -370,12 +376,6 @@ int vmbus_uio_get_subchan(struct vmbus_channel *primary,
if (subid == 0)
continue; /* skip primary channel */
- if (!vmbus_isnew_subchannel(primary, relid))
- continue;
-
- if (!vmbus_uio_ring_present(dev, relid))
- continue; /* Ring may not be ready yet */
-
err = vmbus_uio_sysfs_read(subchan_path, "monitor_id",
&monid, UINT8_MAX);
if (err) {