linux/drivers/hv
Andrea Parri (Microsoft) 9403b66e61 Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal
Since vmbus_chan_sched() dereferences the ring buffer pointer, we have
to make sure that the ring buffer data structures don't get freed while
such dereferencing is happening.  Current code does this by sending an
IPI to the CPU that is allowed to access that ring buffer from interrupt
level, cf., vmbus_reset_channel_cb().  But with the new functionality
to allow changing the CPU that a channel will interrupt, we can't be
sure what CPU will be running the vmbus_chan_sched() function for a
particular channel, so the current IPI mechanism is infeasible.

Instead synchronize vmbus_chan_sched() and vmbus_reset_channel_cb() by
using the (newly introduced) per-channel spin lock "sched_lock".  Move
the test for onchannel_callback being NULL before the "switch" control
statement in vmbus_chan_sched(), in order to not access the ring buffer
if the vmbus_reset_channel_cb() has been completed on the channel.

Suggested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200406001514.19876-7-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-04-23 13:17:12 +00:00
..
channel_mgmt.c Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal 2020-04-23 13:17:12 +00:00
channel.c Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal 2020-04-23 13:17:12 +00:00
connection.c Drivers: hv: vmbus: Replace the per-CPU channel lists with a global array of channels 2020-04-23 13:17:11 +00:00
hv_balloon.c hv_balloon: don't check for memhp_auto_online manually 2020-04-07 10:43:40 -07:00
hv_debugfs.c hv_debugfs: Make hv_debug_root static 2020-04-04 17:47:43 +01:00
hv_fcopy.c hv_utils: Always execute the fcopy and vss callbacks in a tasklet 2020-04-23 13:17:11 +00:00
hv_kvp.c hv_utils: Add the support of hibernation 2020-01-26 22:10:17 -05:00
hv_snapshot.c hv_utils: Always execute the fcopy and vss callbacks in a tasklet 2020-04-23 13:17:11 +00:00
hv_trace_balloon.h hv_balloon: trace post_status 2018-03-06 09:57:17 -08:00
hv_trace.c hv: add SPDX license to trace 2018-03-28 13:24:56 +02:00
hv_trace.h tools: hv: Use the correct style for SPDX License Identifier 2019-08-17 15:29:34 -04:00
hv_util.c - Most of the commits here are work to enable host-initiated hibernation 2020-02-03 14:42:03 +00:00
hv_utils_transport.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 280 2019-06-05 17:36:36 +02:00
hv_utils_transport.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 280 2019-06-05 17:36:36 +02:00
hv.c Drivers: hv: vmbus: Replace the per-CPU channel lists with a global array of channels 2020-04-23 13:17:11 +00:00
hyperv_vmbus.h hv_utils: Always execute the fcopy and vss callbacks in a tasklet 2020-04-23 13:17:11 +00:00
Kconfig clocksource/drivers/hyperv: Enable TSC page clocksource on 32bit 2019-08-23 16:59:54 +02:00
Makefile drivers: hv: vmbus: Introduce latency testing 2019-11-21 20:10:44 -05:00
ring_buffer.c drivers: hv: vmbus: Introduce latency testing 2019-11-21 20:10:44 -05:00
vmbus_drv.c Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal 2020-04-23 13:17:12 +00:00