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| author | Dexuan Cui <decui@microsoft.com> | 2017-01-28 11:46:02 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-01-31 10:59:48 +0100 |
| commit | 433e19cf33d34bb6751c874a9c00980552fe508c (patch) | |
| tree | ce6547ef2987fbb289fa28f03536328a42781651 /drivers/net/hyperv | |
| parent | 191e885a2e130e639bb0c8ee350d7047294f2ce6 (diff) | |
| download | linux-433e19cf33d34bb6751c874a9c00980552fe508c.tar.bz2 | |
Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()
Commit a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
added the proper mb(), but removed the test "prev_write_sz < pending_sz"
when making the signal decision.
As a result, the guest can signal the host unnecessarily,
and then the host can throttle the guest because the host
thinks the guest is buggy or malicious; finally the user
running stress test can perceive intermittent freeze of
the guest.
This patch brings back the test, and properly handles the
in-place consumption APIs used by NetVSC (see get_next_pkt_raw(),
put_pkt_raw() and commit_rd_index()).
Fixes: a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reported-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
Tested-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net/hyperv')
| -rw-r--r-- | drivers/net/hyperv/netvsc.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index 5a1cc089acb7..86e5749226ef 100644 --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -1295,6 +1295,9 @@ void netvsc_channel_cb(void *context) ndev = hv_get_drvdata(device); buffer = get_per_channel_state(channel); + /* commit_rd_index() -> hv_signal_on_read() needs this. */ + init_cached_read_index(channel); + do { desc = get_next_pkt_raw(channel); if (desc != NULL) { @@ -1347,6 +1350,9 @@ void netvsc_channel_cb(void *context) bufferlen = bytes_recvd; } + + init_cached_read_index(channel); + } while (1); if (bufferlen > NETVSC_PACKET_SIZE) |