> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] > Sent: Tuesday, November 1, 2016 9:34 AM > To: devel@xxxxxxxxxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx; KY Srinivasan <kys@xxxxxxxxxxxxx>; > Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Van De Ven, Arjan > <arjan.van.de.ven@xxxxxxxxx> > Subject: [PATCH v2] Drivers: hv: vmbus: Raise retry/wait limits in > vmbus_post_msg() > > DoS protection conditions were altered in WS2016 and now it's easy to > get > -EAGAIN returned from vmbus_post_msg() (e.g. when we try changing MTU on > a > netvsc device in a loop). All vmbus_post_msg() callers don't retry the > operation and we usually end up with a non-functional device or crash. > > While host's DoS protection conditions are unknown to me my tests show > that > it can take up to 10 seconds before the message is sent so doing udelay() > is not an option, we really need to sleep. Almost all vmbus_post_msg() > callers are ready to sleep but there is one special case: > vmbus_initiate_unload() which can be called from interrupt/NMI context > and > we can't sleep there. I'm also not sure about the lonely > vmbus_send_tl_connect_request() which has no in-tree users but its > external > users are most likely waiting for the host to reply so sleeping there is > also appropriate. > > Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > --- > - Changes since v1: keep microsecods delays and udelay() for first > attempts > [KY Srinivasan, Arjan Van De Ven] > --- > drivers/hv/channel.c | 17 +++++++++-------- > drivers/hv/channel_mgmt.c | 10 ++++++---- > drivers/hv/connection.c | 17 ++++++++++++----- > drivers/hv/hyperv_vmbus.h | 2 +- > 4 files changed, 28 insertions(+), 18 deletions(-) > Thank you. Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
