From 4970103e89f4f828669acf3b465e984fdc891e1e Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Wed, 5 Dec 2018 14:11:56 -0800 Subject: [PATCH] bus/vmbus: fix race in subchannel creation 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") Cc: stable@dpdk.org Reported-by: Mohammed Gamal Signed-off-by: Stephen Hemminger --- drivers/bus/vmbus/linux/vmbus_uio.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/bus/vmbus/linux/vmbus_uio.c b/drivers/bus/vmbus/linux/vmbus_uio.c index 12e97e3a42..38df4d724e 100644 --- a/drivers/bus/vmbus/linux/vmbus_uio.c +++ b/drivers/bus/vmbus/linux/vmbus_uio.c @@ -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) { -- 2.20.1