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2017-03-09scripts/spelling.txt: add "disble(d)" pattern and fix typo instancesMasahiro Yamada1-1/+1
Fix typos and add the following to the scripts/spelling.txt: disble||disable disbled||disabled I kept the TSL2563_INT_DISBLED in /drivers/iio/light/tsl2563.c untouched. The macro is not referenced at all, but this commit is touching only comment blocks just in case. Link: http://lkml.kernel.org/r/1481573103-11329-20-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar1-0/+2
<linux/sched/task_stack.h> We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task_stack.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-14vmbus: replace modulus operation with subtractionStephen Hemminger1-3/+6
Takes less clock cycles to check for ring wrap and subtract than to do a modulus instruction. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14vmbus: constify parameters where possibleStephen Hemminger2-15/+13
Functions that just query state of ring buffer can have parameters marked const. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14vmbus: expose hv_begin/end_readStephen Hemminger2-24/+0
In order to implement NAPI in netvsc, the driver needs access to control host interrupt mask. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14vmbus: remove conditional locking of vmbus_writeStephen Hemminger4-19/+9
All current usage of vmbus write uses the acquire_lock flag, therefore having it be optional is unnecessary. This also fixes a sparse warning since sparse doesn't like when a function has conditional locking. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14vmbus: add direct isr callback modeStephen Hemminger4-26/+37
Change the simple boolean batched_reading into a tri-value. For future NAPI support in netvsc driver, the callback needs to occur directly in interrupt handler. Batched mode is also changed to disable host interrupts immediately in interrupt routine (to avoid unnecessary host signals), and the tasklet is rescheduled if more data is detected. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14vmbus: change to per channel taskletStephen Hemminger6-95/+62
Make the event handling tasklet per channel rather than per-cpu. This allows for better fairness when getting lots of data on the same cpu. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14vmbus: put related per-cpu variable togetherStephen Hemminger5-134/+143
The hv_context structure had several arrays which were per-cpu and was allocating small structures (tasklet_struct). Instead use a single per-cpu array. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-10vmbus: remove unused kickq argument to sendpacketStephen Hemminger1-10/+9
Since sendpacket no longer uses kickq argument remove it. Remove it no longer used xmit_more in sendpacket in netvsc as well. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-10vmbus: drop no longer used kick_q argumentStephen Hemminger3-17/+9
The flag to cause notification of host is unused after commit a01a291a282f7c2e ("Drivers: hv: vmbus: Base host signaling strictly on the ring state"). Therefore remove it from the ring buffer internal API. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-10vmbus: use kernel bitops for traversing interrupt maskStephen Hemminger4-54/+29
Use standard kernel operations for find first set bit to traverse the channel bit array. This has added benefit of speeding up lookup on 64 bit and because it uses find first set instruction. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-10Drivers: hv: util: Fix a typoK. Y. Srinivasan1-1/+1
Fix a typo. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-10hv_utils: implement Hyper-V PTP sourceVitaly Kuznetsov1-27/+152
With TimeSync version 4 protocol support we started updating system time continuously through the whole lifetime of Hyper-V guests. Every 5 seconds there is a time sample from the host which triggers do_settimeofday[64](). While the time from the host is very accurate such adjustments may cause issues: - Time is jumping forward and backward, some applications may misbehave. - In case an NTP server runs in parallel and uses something else for time sync (network, PTP,...) system time will never converge. - Systemd starts annoying you by printing "Time has been changed" every 5 seconds to the system log. Instead of doing in-kernel time adjustments offload the work to an NTP client by exposing TimeSync messages as a PTP device. Users may now decide what they want to use as a source. I tested the solution with chrony, the config was: refclock PHC /dev/ptp0 poll 3 dpoll -2 offset 0 The result I'm seeing is accurate enough, the time delta between the guest and the host is almost always within [-10us, +10us], the in-kernel solution was giving us comparable results. I also tried implementing PPS device instead of PTP by using not currently used Hyper-V synthetic timers (we use only one of four for clockevent) but with PPS source only chrony wasn't able to give me the required accuracy, the delta often more that 100us. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-06Merge 4.10-rc7 into char-misc-nextGreg Kroah-Hartman1-0/+1
We want the hv and other fixes in here as well to handle merge and testing issues. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-31Drivers: hv: Log the negotiated IC versions.Alex Ng4-9/+23
Log the negotiated IC versions. Signed-off-by: Alex Ng <alexng@messages.microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-31Drivers: hv: vmbus: Use all supported IC versions to negotiateAlex Ng5-103/+150
Previously, we were assuming that each IC protocol version was tied to a specific host version. For example, some Windows 10 preview hosts only support v3 TimeSync even though driver assumes v4 is supported by all Windows 10 hosts. The guest will stop trying to negotiate even though older supported versions may still be offered by the host. Make IC version negotiation more robust by going through all versions that are supported by the guest. Fixes: 3da0401b4d0e ("Drivers: hv: utils: Fix the mapping between host version and protocol to use") Reported-by: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: Alex Ng <alexng@messages.microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-31Drivers: hv: balloon: add a fall through comment to hv_memory_notifier()Vitaly Kuznetsov1-0/+1
Coverity scan gives a warning when there is fall through in a switch without a comment. This fall through is intentional as ol_waitevent needs to be completed to unblock hv_mem_hot_add() allowing it to process next requests regardless of the result of if we were able to online this block. Reported-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-31Drivers: hv: restore hypervcall page cleanup before kexecVitaly Kuznetsov3-19/+3
We need to cleanup the hypercall page before doing kexec/kdump or the new kernel may crash if it tries to use it. Reuse the now-empty hv_cleanup function renaming it to hyperv_cleanup and moving to the arch specific code. Fixes: 8730046c1498 ("Drivers: hv vmbus: Move Hypercall page setup out of common code") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-31hv_util: switch to using timespec64Vitaly Kuznetsov1-3/+3
do_settimeofday() is deprecated, use do_settimeofday64() instead. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: John Stultz <john.stultz@linaro.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-31Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()Dexuan Cui1-0/+1
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>
2017-01-20Drivers: hv: vmbus: Cleanup hyperv_vmbus.hK. Y. Srinivasan1-150/+2
Get rid of all unused definitions. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Define an APIs to manage interrupt stateK. Y. Srinivasan1-4/+8
As part of cleaning up architecture specific code, define APIs to manage interrupt state. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Define an API to retrieve virtual processor indexK. Y. Srinivasan1-1/+1
As part of cleaning up architecture specific code, define an API to retrieve the virtual procesor index. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Define APIs to manipulate the synthetic interrupt controllerK. Y. Srinivasan1-4/+4
As part of cleaning up architecture specific code, define APIs to manipulate the interrupt controller state. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Define APIs to manipulate the event pageK. Y. Srinivasan1-4/+4
As part of cleaning up architecture specific code, define APIs to manipulate the event page. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Define APIs to manipulate the message pageK. Y. Srinivasan1-4/+4
As part of cleaning up architecture specific code, define APIs to manipulate the message page. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Get rid of an unsused variableK. Y. Srinivasan1-4/+0
The version variable while it is initialized is not used; get rid of it. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: util: Use hv_get_current_tick() to get current tickK. Y. Srinivasan1-1/+2
As part of the effort to interact with Hyper-V in an instruction set architecture independent way, use the new API to get the current tick. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Restructure the clockevents codeK. Y. Srinivasan1-5/+5
Move the relevant code that programs the hypervisor to an architecture specific file. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Move the code to signal end of messageK. Y. Srinivasan2-35/+1
As part of the effort to separate out architecture specific code, move the code for signaling end of message. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Move the check for hypercall page setupK. Y. Srinivasan1-6/+1
As part of the effort to separate out architecture specific code, move the check for detecting if the hypercall page is setup. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Move the crash notification functionK. Y. Srinivasan2-35/+0
As part of the effort to separate out architecture specific code, move the crash notification function. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Move the extracting of Hypervisor version informationK. Y. Srinivasan3-81/+2
As part of the effort to separate out architecture specific code, extract hypervisor version information in an architecture specific file. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-20Drivers: hv: vmbus: Consolidate all Hyper-V specific clocksource codeK. Y. Srinivasan2-103/+0
As part of the effort to separate out architecture specific code, consolidate all Hyper-V specific clocksource code to an architecture specific code. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19Drivers: hv: vmbus: Move Hypercall invocation code out of common codeK. Y. Srinivasan2-53/+0
As part of the effort to separate out architecture specific code, move the hypercall invocation code to an architecture specific file. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19Drivers: hv vmbus: Move Hypercall page setup out of common codeK. Y. Srinivasan1-42/+3
As part of the effort to separate out architecture specific code, move the hypercall page setup to an architecture specific file. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19Drivers: hv: vmbus: Move the definition of generate_guest_id()K. Y. Srinivasan1-43/+0
As part of the effort to separate out architecture specific code, move the definition of generate_guest_id() to x86 specific header file. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19Drivers: hv: vmbus: Move the definition of hv_x64_msr_hypercall_contentsK. Y. Srinivasan1-15/+0
As part of the effort to separate out architecture specific code, move the definition of hv_x64_msr_hypercall_contents to x86 specific header file. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10Drivers: hv: util: Backup: Fix a rescind processing issueK. Y. Srinivasan1-0/+4
VSS may use a char device to support the communication between the user level daemon and the driver. When the VSS channel is rescinded we need to make sure that the char device is fully cleaned up before we can process a new VSS offer from the host. Implement this logic. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10Drivers: hv: util: Fcopy: Fix a rescind processing issueK. Y. Srinivasan1-0/+4
Fcopy may use a char device to support the communication between the user level daemon and the driver. When the Fcopy channel is rescinded we need to make sure that the char device is fully cleaned up before we can process a new Fcopy offer from the host. Implement this logic. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10Drivers: hv: util: kvp: Fix a rescind processing issueK. Y. Srinivasan1-0/+4
KVP may use a char device to support the communication between the user level daemon and the driver. When the KVP channel is rescinded we need to make sure that the char device is fully cleaned up before we can process a new KVP offer from the host. Implement this logic. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10Drivers: hv: vmbus: Fix a rescind handling bugK. Y. Srinivasan2-0/+43
The host can rescind a channel that has been offered to the guest and once the channel is rescinded, the host does not respond to any requests on that channel. Deal with the case where the guest may be blocked waiting for a response from the host. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10hv: make CPU offlining prevention fine-grainedVitaly Kuznetsov2-5/+35
Since commit e513229b4c38 ("Drivers: hv: vmbus: prevent cpu offlining on newer hypervisors") cpu offlining was disabled. It is still true that we can't offline CPUs which have VMBus channels bound to them but we may have 'free' CPUs (e.v. we booted with maxcpus= parameter and onlined CPUs after VMBus was initialized), these CPUs may be disabled without issues. In future, we may even allow closing CPUs which have only sub-channels assinged to them by closing these sub-channels. All devices will continue to work. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10hv: switch to cpuhp state machine for synic init/cleanupVitaly Kuznetsov3-18/+20
To make it possible to online/offline CPUs switch to cpuhp infrastructure for doing hv_synic_init()/hv_synic_cleanup(). Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10Drivers: hv: vmbus: Prevent sending data on a rescinded channelK. Y. Srinivasan1-0/+7
After the channel is rescinded, the host does not read from the rescinded channel. Fail writes to a channel that has already been rescinded. If we permit writes on a rescinded channel, since the host will not respond we will have situations where we will be unable to unload vmbus drivers that cannot have any outstanding requests to the host at the point they are unoaded. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <Stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10hv: don't reset hv_context.tsc_page on crashVitaly Kuznetsov1-2/+3
It may happen that secondary CPUs are still alive and resetting hv_context.tsc_page will cause a consequent crash in read_hv_clock_tsc() as we don't check for it being not NULL there. It is safe as we're not freeing this page anyways. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10hv: init percpu_list in hv_synic_alloc()Vitaly Kuznetsov1-2/+2
Initializing hv_context.percpu_list in hv_synic_alloc() helps to prevent a crash in percpu_channel_enq() when not all CPUs were online during initialization and it naturally belongs there. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10hv: allocate synic pages for all present CPUsVitaly Kuznetsov1-2/+2
It may happen that not all CPUs are online when we do hv_synic_alloc() and in case more CPUs come online later we may try accessing these allocated structures. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-10Drivers: hv: vmbus: Raise retry/wait limits in vmbus_post_msg()Vitaly Kuznetsov4-18/+28
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@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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