Re: [PATCH v2] crypto: qat - adf_dev_stop should not be called in atomic context

[Herbert Xu]

On Wed, Apr 06, 2016 at 11:01:54AM -0700, Tadeusz Struk wrote:
> VFs call adf_dev_stop() from a PF to VF interrupt bottom half.
> This causes an oops "scheduling while atomic", because it tries
> to acquire a mutex to un-register crypto algorithms.
> This patch fixes the issue by calling adf_dev_stop() asynchronously.

Applied.
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Email: Herbert Xu 
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[PATCH v2] crypto: qat - adf_dev_stop should not be called in atomic context

[Tadeusz Struk]

VFs call adf_dev_stop() from a PF to VF interrupt bottom half.
This causes an oops "scheduling while atomic", because it tries
to acquire a mutex to un-register crypto algorithms.
This patch fixes the issue by calling adf_dev_stop() asynchronously.

Changes in v2:
 - change kthread to a work queue.

Signed-off-by: Tadeusz Struk 
---
 drivers/crypto/qat/qat_common/adf_common_drv.h |2 +
 drivers/crypto/qat/qat_common/adf_ctl_drv.c|6 ++
 drivers/crypto/qat/qat_common/adf_vf_isr.c |   59 +++-
 3 files changed, 64 insertions(+), 3 deletions(-)

diff --git a/drivers/crypto/qat/qat_common/adf_common_drv.h 
b/drivers/crypto/qat/qat_common/adf_common_drv.h
index c9e4d46..fd096ed 100644
--- a/drivers/crypto/qat/qat_common/adf_common_drv.h
+++ b/drivers/crypto/qat/qat_common/adf_common_drv.h
@@ -144,6 +144,8 @@ void adf_disable_aer(struct adf_accel_dev *accel_dev);
 void adf_dev_restore(struct adf_accel_dev *accel_dev);
 int adf_init_aer(void);
 void adf_exit_aer(void);
+int adf_init_vf_wq(void);
+void adf_exit_vf_wq(void);
 int adf_init_admin_comms(struct adf_accel_dev *accel_dev);
 void adf_exit_admin_comms(struct adf_accel_dev *accel_dev);
 int adf_send_admin_init(struct adf_accel_dev *accel_dev);
diff --git a/drivers/crypto/qat/qat_common/adf_ctl_drv.c 
b/drivers/crypto/qat/qat_common/adf_ctl_drv.c
index 48a1248..116ddda 100644
--- a/drivers/crypto/qat/qat_common/adf_ctl_drv.c
+++ b/drivers/crypto/qat/qat_common/adf_ctl_drv.c
@@ -471,12 +471,17 @@ static int __init adf_register_ctl_device_driver(void)
if (adf_init_aer())
goto err_aer;
 
+   if (adf_init_vf_wq())
+   goto err_vf_wq;
+
if (qat_crypto_register())
goto err_crypto_register;
 
return 0;
 
 err_crypto_register:
+   adf_exit_vf_wq();
+err_vf_wq:
adf_exit_aer();
 err_aer:
adf_chr_drv_destroy();
@@ -489,6 +494,7 @@ static void __exit adf_unregister_ctl_device_driver(void)
 {
adf_chr_drv_destroy();
adf_exit_aer();
+   adf_exit_vf_wq();
qat_crypto_unregister();
adf_clean_vf_map(false);
mutex_destroy(_ctl_lock);
diff --git a/drivers/crypto/qat/qat_common/adf_vf_isr.c 
b/drivers/crypto/qat/qat_common/adf_vf_isr.c
index 09427b3..c3d5016 100644
--- a/drivers/crypto/qat/qat_common/adf_vf_isr.c
+++ b/drivers/crypto/qat/qat_common/adf_vf_isr.c
@@ -51,6 +51,7 @@
 #include 
 #include 
 #include 
+#include 
 #include "adf_accel_devices.h"
 #include "adf_common_drv.h"
 #include "adf_cfg.h"
@@ -64,6 +65,13 @@
 #define ADF_VINTSOU_BUNBIT(0)
 #define ADF_VINTSOU_PF2VF  BIT(1)
 
+static struct workqueue_struct *adf_vf_stop_wq;
+
+struct adf_vf_stop_data {
+   struct adf_accel_dev *accel_dev;
+   struct work_struct work;
+};
+
 static int adf_enable_msi(struct adf_accel_dev *accel_dev)
 {
struct adf_accel_pci *pci_dev_info = _dev->accel_pci_dev;
@@ -90,6 +98,20 @@ static void adf_disable_msi(struct adf_accel_dev *accel_dev)
pci_disable_msi(pdev);
 }
 
+static void adf_dev_stop_async(struct work_struct *work)
+{
+   struct adf_vf_stop_data *stop_data =
+   container_of(work, struct adf_vf_stop_data, work);
+   struct adf_accel_dev *accel_dev = stop_data->accel_dev;
+
+   adf_dev_stop(accel_dev);
+   adf_dev_shutdown(accel_dev);
+
+   /* Re-enable PF2VF interrupts */
+   adf_enable_pf2vf_interrupts(accel_dev);
+   kfree(stop_data);
+}
+
 static void adf_pf2vf_bh_handler(void *data)
 {
struct adf_accel_dev *accel_dev = data;
@@ -107,11 +129,27 @@ static void adf_pf2vf_bh_handler(void *data)
goto err;
 
switch ((msg & ADF_PF2VF_MSGTYPE_MASK) >> ADF_PF2VF_MSGTYPE_SHIFT) {
-   case ADF_PF2VF_MSGTYPE_RESTARTING:
+   case ADF_PF2VF_MSGTYPE_RESTARTING: {
+   struct adf_vf_stop_data *stop_data;
+
dev_dbg(_DEV(accel_dev),
"Restarting msg received from PF 0x%x\n", msg);
-   adf_dev_stop(accel_dev);
-   break;
+
+   stop_data = kzalloc(sizeof(*stop_data), GFP_ATOMIC);
+   if (!stop_data) {
+   dev_err(_DEV(accel_dev),
+   "Couldn't schedule stop for vf_%d\n",
+   accel_dev->accel_id);
+   return;
+   }
+   stop_data->accel_dev = accel_dev;
+   INIT_WORK(_data->work, adf_dev_stop_async);
+   queue_work(adf_vf_stop_wq, _data->work);
+   /* To ack, clear the PF2VFINT bit */
+   msg &= ~BIT(0);
+   ADF_CSR_WR(pmisc_bar_addr, hw_data->get_pf2vf_offset(0), msg);
+   return;
+   }
case ADF_PF2VF_MSGTYPE_VERSION_RESP:
dev_dbg(_DEV(accel_dev),
"Version resp received from PF 0x%x\n", msg);
@@ -278,3 +316,18 @@ err_out:
return -EFAULT;