[dpdk-stable] [PATCH] net/failsafe: fix Rx clean race
matan at mellanox.com
Sun Oct 22 07:51:08 CEST 2017
In case of plug out, the RMV interrupt callback sets the remove flag of
the removed sub-device. The next hotplug alarm cycle should read this
flag and if the data path are clean it should remove the sub-device.
In case of fail-safe RX burst calling from application, fail-afe tries
to call to all STARTED sub-device rx_burst functions. The remove flag
is not checked here and fail-safe may call to the removed sub-device
The above 2 cases run in different threads and there is a race between
the removed sub-device RX clean check to the removed sub-device
rx_burst call makes the sub device RX unclean.
If the application calls to rx_burst in loop, the probability to get RX
clean is not enough, especially when there are few sub-devices or if the
rx_burst function of the removed sub-device takes a lot of time.
Each time the sub-device data path is unclean, the second oportunity to
check it again should be only in the hotplug alarm next cycle; the
default time between cycles is 2 seconds.
In this loop when fail-safe tries to remove the sub-device, the
sub-device may appear back and fail-safe cannot plug it in back until
the removal process is completted. In this time fail-safe may lose the
primary sub-device services and may hurt application performance.
This patch adds a remove flag check in safe rx_burst function.
By this way, at most one more hotplug alarm cycle is necessary
to get the sub-device clean for actual removal.
Fixes: 72a57bfd9a0e ("net/failsafe: add fast burst functions")
Cc: stable at dpdk.org
Signed-off-by: Matan Azrad <matan at mellanox.com>
drivers/net/failsafe/failsafe_rxtx.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/failsafe/failsafe_rxtx.c b/drivers/net/failsafe/failsafe_rxtx.c
index 7311421..70157c8 100644
@@ -43,7 +43,8 @@
return (ETH(sdev) == NULL) ||
(ETH(sdev)->rx_pkt_burst == NULL) ||
- (sdev->state != DEV_STARTED);
+ (sdev->state != DEV_STARTED) ||
+ (sdev->remove != 0);
static inline int
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