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path: root/drivers/hv/channel.c
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2017-03-30Drivers: hv: vmbus: Don't leak memory when a channel is rescindedK. Y. Srinivasan
commit 5e030d5ce9d99a899b648413139ff65bab12b038 upstream. When we close a channel that has been rescinded, we will leak memory since vmbus_teardown_gpadl() returns an error. Fix this so that we can properly cleanup the memory allocated to the ring buffers. Fixes: ccb61f8a99e6 ("Drivers: hv: vmbus: Fix a rescind handling bug") Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Dexuan Cui <decui@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12Drivers: hv: vmbus: Fix a rescind handling bugK. Y. Srinivasan
commit ccb61f8a99e6c29df4fb96a65dad4fad740d5be9 upstream. The host can rescind a channel that has been offered to the guest and once the channel is rescinded, the host does not respond to any requests on that channel.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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12Drivers: hv: vmbus: Raise retry/wait limits in vmbus_post_msg()Vitaly Kuznetsov
commit c0bb03924f1a80e7f65900e36c8e6b3dc167c5f8 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14Drivers: hv: vmbus: On the read path cleanup the logic to interrupt the hostK. Y. Srinivasan
commit 3372592a140db69fd63837e81f048ab4abf8111e upstream. Signal the host when we determine the host is to be signaled - on th read path. The currrent code determines the need to signal in the ringbuffer code and actually issues the signal elsewhere. This can result in the host viewing this interrupt as spurious since the host may also poll the channel. Make the necessary adjustments. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14Drivers: hv: vmbus: On write cleanup the logic to interrupt the hostK. Y. Srinivasan
commit 1f6ee4e7d83586c8b10bd4f2f4346353d04ce884 upstream. Signal the host when we determine the host is to be signaled. The currrent code determines the need to signal in the ringbuffer code and actually issues the signal elsewhere. This can result in the host viewing this interrupt as spurious since the host may also poll the channel. Make the necessary adjustments. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14Drivers: hv: vmbus: Base host signaling strictly on the ring stateK. Y. Srinivasan
commit 74198eb4a42c4a3c4fbef08fa01a291a282f7c2e upstream. One of the factors that can result in the host concluding that a given guest in mounting a DOS attack is if the guest generates interrupts to the host when the host is not expecting it. If these "spurious" interrupts reach a certain rate, the host can throttle the guest to minimize the impact. The host computation of the "expected number of interrupts" is strictly based on the ring transitions. Until the host logic is fixed, base the guest logic to interrupt solely on the ring state. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-02Drivers: hv: ring_buffer: wrap around mappings for ring buffersVitaly Kuznetsov
Make it possible to always use a single memcpy() or to provide a direct link to a packet on the ring buffer by creating virtual mapping for two copies of the ring buffer with vmap(). Utilize currently empty hv_ringbuffer_cleanup() to do the unmap. While on it, replace sizeof(struct hv_ring_buffer) check in hv_ringbuffer_init() with BUILD_BUG_ON() as it is a compile time check. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-02Drivers: hv: cleanup vmbus_open() for wrap around mappingsVitaly Kuznetsov
In preparation for doing wrap around mappings for ring buffers cleanup vmbus_open() function: - check that ring sizes are PAGE_SIZE aligned (they are for all in-kernel drivers now); - kfree(open_info) on error only after we kzalloc() it (not an issue as it is valid to call kfree(NULL); - rename poorly named labels; - use alloc_pages() instead of __get_free_pages() as we need struct page pointer for future. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31Drivers: hv: vmbus: Implement a mechanism to tag the channel for low latencyK. Y. Srinivasan
On Hyper-V, performance critical channels use the monitor mechanism to signal the host when the guest posts mesages for the host. This mechanism minimizes the hypervisor intercepts and also makes the host more efficient in that each time the host is woken up, it processes a batch of messages as opposed to just one. The goal here is improve the throughput and this is at the expense of increased latency. Implement a mechanism to let the client driver decide if latency is important. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31Drivers: hv: vmbus: Enable explicit signaling policy for NIC channelsK. Y. Srinivasan
For synthetic NIC channels, enable explicit signaling policy as netvsc wants to explicitly control when the host is to be signaled. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31Drivers: hv: vmbus: fix the race when querying & updating the percpu listDexuan Cui
There is a rare race when we remove an entry from the global list hv_context.percpu_list[cpu] in hv_process_channel_removal() -> percpu_channel_deq() -> list_del(): at this time, if vmbus_on_event() -> process_chn_event() -> pcpu_relid2channel() is trying to query the list, we can get the kernel fault. Similarly, we also have the issue in the code path: vmbus_process_offer() -> percpu_channel_enq(). We can resolve the issue by disabling the tasklet when updating the list. The patch also moves vmbus_release_relid() to a later place where the channel has been removed from the per-cpu and the global lists. Reported-by: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31Drivers: hv: get rid of timeout in vmbus_open()Vitaly Kuznetsov
vmbus_teardown_gpadl() can result in infinite wait when it is called on 5 second timeout in vmbus_open(). The issue is caused by the fact that gpadl teardown operation won't ever succeed for an opened channel and the timeout isn't always enough. As a guest, we can always trust the host to respond to our request (and there is nothing we can do if it doesn't). 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>
2016-08-31Drivers: hv: don't leak memory in vmbus_establish_gpadl()Vitaly Kuznetsov
In some cases create_gpadl_header() allocates submessages but we never free them. 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>
2016-08-31Drivers: hv: get rid of redundant messagecount in create_gpadl_header()Vitaly Kuznetsov
We use messagecount only once in vmbus_establish_gpadl() to check if it is safe to iterate through the submsglist. We can just initialize the list header in all cases in create_gpadl_header() instead. 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>
2016-02-08Drivers: hv: vmbus: Give control over how the ring access is serializedK. Y. Srinivasan
On the channel send side, many of the VMBUS device drivers explicity serialize access to the outgoing ring buffer. Give more control to the VMBUS device drivers in terms how to serialize accesss to the outgoing ring buffer. The default behavior will be to aquire the ring lock to preserve the current behavior. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-08Drivers: hv: vmbus: define a new VMBus message type for hvsockDexuan Cui
A function to send the type of message is also added. The coming net/hvsock driver will use this function to proactively request the host to offer a VMBus channel for a new hvsock connection. Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-08Drivers: hv: vmbus: vmbus_sendpacket_ctl: hvsock: avoid unnecessary signalingDexuan Cui
When the hvsock channel's outbound ringbuffer is full (i.e., hv_ringbuffer_write() returns -EAGAIN), we should avoid the unnecessary signaling the host. Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-15Drivers: hv: ring_buffer: eliminate hv_ringbuffer_peek()Vitaly Kuznetsov
Currently, there is only one user for hv_ringbuffer_read()/ hv_ringbuffer_peak() functions and the usage of these functions is: - insecure as we drop ring_lock between them, someone else (in theory only) can acquire it in between; - non-optimal as we do a number of things (acquire/release the above mentioned lock, calculate available space on the ring, ...) twice and this path is performance-critical. Remove hv_ringbuffer_peek() moving the logic from __vmbus_recvpacket() to hv_ringbuffer_read(). 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>
2015-12-15Drivers: hv: remove code duplication between ↵Vitaly Kuznetsov
vmbus_recvpacket()/vmbus_recvpacket_raw() vmbus_recvpacket() and vmbus_recvpacket_raw() are almost identical but there are two discrepancies: 1) vmbus_recvpacket() doesn't propagate errors from hv_ringbuffer_read() which looks like it is not desired. 2) There is an error message printed in packetlen > bufferlen case in vmbus_recvpacket(). I'm removing it as it is usless for users to see such messages and /vmbus_recvpacket_raw() doesn't have it. 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>
2015-12-15Drivers: hv: vmbus: Fix a Host signaling bugK. Y. Srinivasan
Currently we have two policies for deciding when to signal the host: One based on the ring buffer state and the other based on what the VMBUS client driver wants to do. Consider the case when the client wants to explicitly control when to signal the host. In this case, if the client were to defer signaling, we will not be able to signal the host subsequently when the client does want to signal since the ring buffer state will prevent the signaling. Implement logic to have only one signaling policy in force for a given channel. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Tested-by: Haiyang Zhang <haiyangz@microsoft.com> Cc: <stable@vger.kernel.org> # v4.2+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-15Drivers: hv: vmbus: fix rescind-offer handling for device without a driverDexuan Cui
In the path vmbus_onoffer_rescind() -> vmbus_device_unregister() -> device_unregister() -> ... -> __device_release_driver(), we can see for a device without a driver loaded: dev->driver is NULL, so dev->bus->remove(dev), namely vmbus_remove(), isn't invoked. As a result, vmbus_remove() -> hv_process_channel_removal() isn't invoked and some cleanups(like sending a CHANNELMSG_RELID_RELEASED message to the host) aren't done. We can demo the issue this way: 1. rmmod hv_utils; 2. disable the Heartbeat Integration Service in Hyper-V Manager and lsvmbus shows the device disappears. 3. re-enable the Heartbeat in Hyper-V Manager and modprobe hv_utils, but lsvmbus shows the device can't appear again. This is because, the host thinks the VM hasn't released the relid, so can't re-offer the device to the VM. We can fix the issue by moving hv_process_channel_removal() from vmbus_close_internal() to vmbus_device_release(), since the latter is always invoked on device_unregister(), whether or not the dev has a driver loaded. Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-15Drivers: hv: vmbus: do sanity check of channel state in vmbus_close_internal()Dexuan Cui
This fixes an incorrect assumption of channel state in the function. Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-15Drivers: hv: vmbus: serialize process_chn_event() and vmbus_close_internal()Dexuan Cui
process_chn_event(), running in the tasklet, can race with vmbus_close_internal() in the case of SMP guest, e.g., when the former is accessing channel->inbound.ring_buffer, the latter could be freeing the ring_buffer pages. To resolve the race, we can serialize them by disabling the tasklet when the latter is running here. Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-05Drivers: hv: vmbus: Permit sending of packets without payloadK. Y. Srinivasan
The guest may have to send a completion packet back to the host. To support this usage, permit sending a packet without a payload - we would be only sending the descriptor in this case. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-06-12Drivers: hv: vmbus: Allocate ring buffer memory in NUMA aware fashionK. Y. Srinivasan
Allocate ring buffer memory from the NUMA node assigned to the channel. Since this is a performance and not a correctness issue, if the node specific allocation were to fail, fall back and allocate without specifying the node. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24Drivers: hv: vmbus: do cleanup on all vmbus_open() failure pathsVitaly Kuznetsov
In case there was an error reported in the response to the CHANNELMSG_OPENCHANNEL call we need to do the cleanup as a vmbus_open() user won't be doing it after receiving an error. The cleanup should be done on all failure paths. We also need to avoid returning open_info->response.open_result.status as the return value as all other errors we return from vmbus_open() are -EXXX and vmbus_open() callers are not supposed to analyze host error codes. 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>
2015-03-25Drivers: hv: vmbus: Fix a siganlling host signalling issueK. Y. Srinivasan
Handle the case when the write to the ringbuffer fails. In this case, unconditionally signal the host. Since we may have deferred signalling the host based on the kick_q parameter, signalling the host unconditionally in this case deals with the issue. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-25Drivers: hv: vmbus: Export the vmbus_sendpacket_pagebuffer_ctl()K. Y. Srinivasan
Export the vmbus_sendpacket_pagebuffer_ctl() interface. This export will be used by the netvsc driver. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-25Drivers: hv: vmbus: Fix a bug in rescind processing in vmbus_close_internal()K. Y. Srinivasan
When a channel has been rescinded, the close operation is a noop. Restructure the code so we deal with the rescind condition after we properly cleanup the channel. I would like to thank Dexuan Cui <decui@microsoft.com> for observing this problem. The current code leaks memory when the channel is rescinded. The current char-next branch is broken and this patch fixes the bug. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-02Drivers: hv: vmbus: Suport an API to send packet with additional controlK. Y. Srinivasan
Implement an API that gives additional control on the what VMBUS flags will be set as well as if the host needs to be signalled. This API will be useful for clients that want to batch up requests to the host. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-02Drivers: hv: vmbus: Suport an API to send pagebuffers with additional controlK. Y. Srinivasan
Implement an API for sending pagebuffers that gives more control to the client in terms of setting the vmbus flags as well as deciding when to notify the host. This will be useful for enabling batch processing. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-02Drivers: hv: vmbus: Introduce a function to remove a rescinded offerK. Y. Srinivasan
In response to a rescind message, we need to remove the channel and the corresponding device. Cleanup this code path by factoring out the code to remove a channel. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-02Drivers: hv: vmbus: Fix a bug in the error path in vmbus_open()K. Y. Srinivasan
Correctly rollback state if the failure occurs after we have handed over the ownership of the buffer to 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>
2015-03-02hv: channel: match var type to return type of wait_for_completionNicholas Mc Guire
return type of wait_for_completion_timeout is unsigned long not int, this patch changes the type of t from int to unsigned long. Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-02hv: vmbus_open(): reset the channel state on ENOMEMDexuan Cui
Without this patch, the state is put to CHANNEL_OPENING_STATE, and when the driver is loaded next time, vmbus_open() will fail immediately due to newchannel->state != CHANNEL_OPEN_STATE. CC: "K. Y. Srinivasan" <kys@microsoft.com> Signed-off-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Jason Wang <jasowang@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-25Drivers: hv: rename sc_lock to the more generic lockVitaly Kuznetsov
sc_lock spinlock in struct vmbus_channel is being used to not only protect the sc_list field, e.g. vmbus_open() function uses it to implement test-and-set access to the state field. Rename it to the more generic 'lock' and add the description. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-25Drivers: hv: vmbus: Support a vmbus API for efficiently sending page arraysK. Y. Srinivasan
Currently, the API for sending a multi-page buffer over VMBUS is limited to a maximum pfn array of MAX_MULTIPAGE_BUFFER_COUNT. This limitation is not imposed by the host and unnecessarily limits the maximum payload that can be sent. Implement an API that does not have this restriction. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-25Drivers: hv: vmbus: Fix a bug in vmbus_establish_gpadl()K. Y. Srinivasan
Correctly compute the local (gpadl) handle. I would like to thank Michael Brown <mcb30@ipxe.org> for seeing this bug. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reported-by: Michael Brown <mcb30@ipxe.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-24Drivers: hv: vmbus: Properly protect calls to smp_processor_id()K. Y. Srinivasan
Disable preemption when sampling current processor ID when preemption is otherwise possible. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-24Drivers: hv: vmbus: Cleanup vmbus_close_internal()K. Y. Srinivasan
Eliminate calls to BUG_ON() in vmbus_close_internal(). We have chosen to potentially leak memory, than crash the guest in case of failures. In this version of the patch I have addressed comments from Dan Carpenter (dan.carpenter@oracle.com). Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-24Drivers: hv: vmbus: Fix a bug in vmbus_open()K. Y. Srinivasan
Fix a bug in vmbus_open() and properly propagate the error. I would like to thank Dexuan Cui <decui@microsoft.com> for identifying the issue. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-24Drivers: hv: vmbus: Cleanup vmbus_establish_gpadl()K. Y. Srinivasan
Eliminate the call to BUG_ON() by waiting for the host to respond. We are trying to reclaim the ownership of memory that was given to the host and so we will have to wait until the host responds. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-24Drivers: hv: vmbus: Cleanup vmbus_teardown_gpadl()K. Y. Srinivasan
Eliminate calls to BUG_ON() by properly handling errors. In cases where rollback is possible, we will return the appropriate error to have the calling code decide how to rollback state. In the case where we are transferring ownership of the guest physical pages to the host, we will wait for the host to respond. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-09hyperv: remove meaningless pr_err() in vmbus_recvpacket_raw()Jason Wang
All its callers depends on the return value of -ENOBUFS to reallocate a bigger buffer and retry the receiving. So there's no need to call pr_err() here since it was not a real issue, otherwise syslog will be flooded by this false warning. Cc: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-03hv: Remove unnecessary comparison of unsigned against 0Tobias Klauser
pfncount is of type u32 and thus can never be smaller than 0. Found by the coverity scanner, CID 143213. Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-03Drivers: hv: Eliminate the channel spinlock in the callback pathK. Y. Srinivasan
By ensuring that we set the callback handler to NULL in the channel close path on the same CPU that the channel is bound to, we can eliminate this lock acquisition and release in a performance critical path. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-07Drivers: hv: vmbus: Cleanup the packet send pathK. Y. Srinivasan
The current channel code is using scatterlist abstraction to pass data to the ringbuffer API on the send path. This causes unnecessary translations between virtual and physical addresses. Fix this. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-28hyperv: Add support for physically discontinuous receive bufferHaiyang Zhang
This will allow us to use bigger receive buffer, and prevent allocation failure due to fragmented memory. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-09-26hv: vmbus: fix vmbus_recvpacket_raw() return codeDan Carpenter
Don't return success if the buffer has not been initialized. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-09-26hv: delete vmbus_get_debug_info()Greg Kroah-Hartman
It's only used once, only contains 2 function calls, so just make those calls directly, deleting the function, and the now unneeded structure entirely. Tested-by: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>