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 <[email protected]>
Tested-by: Dexuan Cui <[email protected]>
Signed-off-by: Vitaly Kuznetsov <[email protected]>
---
This patch may be considered for stable as it fixes a regression introduced in
stable.
---
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(-)
diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c
index 9aee601..a5596a6 100644
--- a/drivers/hv/hv_fcopy.c
+++ b/drivers/hv/hv_fcopy.c
@@ -71,7 +71,6 @@ static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
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.
*/
@@ -331,7 +330,6 @@ 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)
@@ -339,7 +337,6 @@ int hv_fcopy_init(struct hv_util_service *srv)
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.
@@ -361,5 +358,4 @@ 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);
}
diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index de26371..a1adfe2 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -101,7 +101,6 @@ static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
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.
@@ -714,7 +713,6 @@ 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
@@ -723,7 +721,6 @@ 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.
@@ -747,5 +744,4 @@ 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);
}
diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index bcc03f0..e659d1b 100644
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -79,7 +79,6 @@ 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);
@@ -361,13 +360,11 @@ 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");
@@ -400,5 +397,4 @@ 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);
}
diff --git a/drivers/hv/hv_utils_transport.c b/drivers/hv/hv_utils_transport.c
index c235a95..4402a71 100644
--- 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 *inode, struct file *file)
* 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_transport_init(const char *name,
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 hvutil_transport *hvt)
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);
}
diff --git a/drivers/hv/hv_utils_transport.h b/drivers/hv/hv_utils_transport.h
index d98f522..79afb62 100644
--- 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,
--
2.9.3
> From: Vitaly Kuznetsov [mailto:[email protected]]
> Sent: Thursday, March 2, 2017 17:48
> To: [email protected]
> Cc: [email protected]; KY Srinivasan <[email protected]>; Haiyang
> Zhang <[email protected]>; Stephen Hemminger
> <[email protected]>; Dexuan Cui <[email protected]>; Alex Ng (LIS)
> <[email protected]>
> Subject: [PATCH] Drivers: hv: util: move waiting for release to hv_utils_transport
> itself
>
> 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 <[email protected]>
> Tested-by: Dexuan Cui <[email protected]>
> Signed-off-by: Vitaly Kuznetsov <[email protected]>
Acked-by: Dexuan Cui <[email protected]>
On Thu, 2 Mar 2017 10:47:49 +0100
Vitaly Kuznetsov <[email protected]> wrote:
> 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 <[email protected]>
> Tested-by: Dexuan Cui <[email protected]>
> Signed-off-by: Vitaly Kuznetsov <[email protected]>
Acked-by: Stephen Hemminger <[email protected]>