This is a note to let you know that I've just added the patch titled
Drivers: hv: util: move waiting for release to hv_utils_transport itself
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: drivers-hv-util-move-waiting-for-release-to-hv_utils_transport-itself.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Mon Dec 18 14:12:34 CET 2017
From: Vitaly Kuznetsov vkuznets@redhat.com Date: Sat, 4 Mar 2017 18:13:59 -0700 Subject: Drivers: hv: util: move waiting for release to hv_utils_transport itself
From: Vitaly Kuznetsov vkuznets@redhat.com
[ Upstream commit e9c18ae6eb2b312f16c63e34b43ea23926daa398 ]
Waiting for release_event in all three drivers introduced issues on release as on_reset() hook is not always called. E.g. if the device was never opened we will never get the completion.
Move the waiting code to hvutil_transport_destroy() and make sure it is only called when the device is open. hvt->lock serialization should guarantee the absence of races.
Fixes: 5a66fecbf6aa ("Drivers: hv: util: kvp: Fix a rescind processing issue") Fixes: 20951c7535b5 ("Drivers: hv: util: Fcopy: Fix a rescind processing issue") Fixes: d77044d142e9 ("Drivers: hv: util: Backup: Fix a rescind processing issue")
Reported-by: Dexuan Cui decui@microsoft.com Tested-by: Dexuan Cui decui@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 Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/hv/hv_fcopy.c | 4 ---- drivers/hv/hv_kvp.c | 4 ---- drivers/hv/hv_snapshot.c | 4 ---- drivers/hv/hv_utils_transport.c | 12 ++++++++---- drivers/hv/hv_utils_transport.h | 1 + 5 files changed, 9 insertions(+), 16 deletions(-)
--- a/drivers/hv/hv_fcopy.c +++ b/drivers/hv/hv_fcopy.c @@ -61,7 +61,6 @@ static DECLARE_WORK(fcopy_send_work, fco static const char fcopy_devname[] = "vmbus/hv_fcopy"; static u8 *recv_buffer; static struct hvutil_transport *hvt; -static struct completion release_event; /* * This state maintains the version number registered by the daemon. */ @@ -322,7 +321,6 @@ static void fcopy_on_reset(void)
if (cancel_delayed_work_sync(&fcopy_timeout_work)) fcopy_respond_to_host(HV_E_FAIL); - complete(&release_event); }
int hv_fcopy_init(struct hv_util_service *srv) @@ -330,7 +328,6 @@ int hv_fcopy_init(struct hv_util_service recv_buffer = srv->recv_buffer; fcopy_transaction.recv_channel = srv->channel;
- init_completion(&release_event); /* * When this driver loads, the user level daemon that * processes the host requests may not yet be running. @@ -352,5 +349,4 @@ void hv_fcopy_deinit(void) fcopy_transaction.state = HVUTIL_DEVICE_DYING; cancel_delayed_work_sync(&fcopy_timeout_work); hvutil_transport_destroy(hvt); - wait_for_completion(&release_event); } --- a/drivers/hv/hv_kvp.c +++ b/drivers/hv/hv_kvp.c @@ -88,7 +88,6 @@ static DECLARE_WORK(kvp_sendkey_work, kv static const char kvp_devname[] = "vmbus/hv_kvp"; static u8 *recv_buffer; static struct hvutil_transport *hvt; -static struct completion release_event; /* * Register the kernel component with the user-level daemon. * As part of this registration, pass the LIC version number. @@ -717,7 +716,6 @@ static void kvp_on_reset(void) if (cancel_delayed_work_sync(&kvp_timeout_work)) kvp_respond_to_host(NULL, HV_E_FAIL); kvp_transaction.state = HVUTIL_DEVICE_INIT; - complete(&release_event); }
int @@ -726,7 +724,6 @@ hv_kvp_init(struct hv_util_service *srv) recv_buffer = srv->recv_buffer; kvp_transaction.recv_channel = srv->channel;
- init_completion(&release_event); /* * When this driver loads, the user level daemon that * processes the host requests may not yet be running. @@ -750,5 +747,4 @@ void hv_kvp_deinit(void) cancel_delayed_work_sync(&kvp_timeout_work); cancel_work_sync(&kvp_sendkey_work); hvutil_transport_destroy(hvt); - wait_for_completion(&release_event); } --- a/drivers/hv/hv_snapshot.c +++ b/drivers/hv/hv_snapshot.c @@ -66,7 +66,6 @@ static int dm_reg_value; static const char vss_devname[] = "vmbus/hv_vss"; static __u8 *recv_buffer; static struct hvutil_transport *hvt; -static struct completion release_event;
static void vss_timeout_func(struct work_struct *dummy); static void vss_handle_request(struct work_struct *dummy); @@ -331,13 +330,11 @@ static void vss_on_reset(void) if (cancel_delayed_work_sync(&vss_timeout_work)) vss_respond_to_host(HV_E_FAIL); vss_transaction.state = HVUTIL_DEVICE_INIT; - complete(&release_event); }
int hv_vss_init(struct hv_util_service *srv) { - init_completion(&release_event); if (vmbus_proto_version < VERSION_WIN8_1) { pr_warn("Integration service 'Backup (volume snapshot)'" " not supported on this host version.\n"); @@ -368,5 +365,4 @@ void hv_vss_deinit(void) cancel_delayed_work_sync(&vss_timeout_work); cancel_work_sync(&vss_handle_request_work); hvutil_transport_destroy(hvt); - wait_for_completion(&release_event); } --- a/drivers/hv/hv_utils_transport.c +++ b/drivers/hv/hv_utils_transport.c @@ -182,10 +182,11 @@ static int hvt_op_release(struct inode * * connects back. */ hvt_reset(hvt); - mutex_unlock(&hvt->lock);
if (mode_old == HVUTIL_TRANSPORT_DESTROY) - hvt_transport_free(hvt); + complete(&hvt->release); + + mutex_unlock(&hvt->lock);
return 0; } @@ -304,6 +305,7 @@ struct hvutil_transport *hvutil_transpor
init_waitqueue_head(&hvt->outmsg_q); mutex_init(&hvt->lock); + init_completion(&hvt->release);
spin_lock(&hvt_list_lock); list_add(&hvt->list, &hvt_list); @@ -351,6 +353,8 @@ void hvutil_transport_destroy(struct hvu if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0) cn_del_callback(&hvt->cn_id);
- if (mode_old != HVUTIL_TRANSPORT_CHARDEV) - hvt_transport_free(hvt); + if (mode_old == HVUTIL_TRANSPORT_CHARDEV) + wait_for_completion(&hvt->release); + + hvt_transport_free(hvt); } --- a/drivers/hv/hv_utils_transport.h +++ b/drivers/hv/hv_utils_transport.h @@ -41,6 +41,7 @@ struct hvutil_transport { int outmsg_len; /* its length */ wait_queue_head_t outmsg_q; /* poll/read wait queue */ struct mutex lock; /* protects struct members */ + struct completion release; /* synchronize with fd release */ };
struct hvutil_transport *hvutil_transport_init(const char *name,
Patches currently in stable-queue which might be from vkuznets@redhat.com are
queue-4.9/drivers-hv-util-move-waiting-for-release-to-hv_utils_transport-itself.patch