habanalabs: reset after device is actually released

The device is actually released only after the refcnt of the hpriv
structure is 0, which means all its contexts were closed.

If we reset the device while a context is still open, there are
possibilities for unexpected behavior and crashes. For example, if the
process has a mapping of a register block that is now currently being
reset, and the process writes/reads to that block during the reset,
the device can get stuck.

Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

diff --git a/drivers/misc/habanalabs/common/device.c b/drivers/misc/habanalabs/common/device.c
index c74bdf4ae6aa8fb9946f59aa7a97aee08c68718b..cba23e5f1bb361e6d16f3832dbd38219d514e273 100644 (file)
--- a/drivers/misc/habanalabs/common/device.c
+++ b/drivers/misc/habanalabs/common/device.c
@@ -70,6 +70,22 @@ static void hpriv_release(struct kref *ref)
        mutex_unlock(&hdev->fpriv_list_lock);
 
        kfree(hpriv);
+
+       if (hdev->reset_upon_device_release) {
+               u64 idle_mask[HL_BUSY_ENGINES_MASK_EXT_SIZE] = {0};
+
+               /* We try soft reset first */
+               hl_device_reset(hdev, false, false);
+
+               /* If device is not idle perform hard reset */
+               if (!hdev->asic_funcs->is_device_idle(hdev, idle_mask,
+                               HL_BUSY_ENGINES_MASK_EXT_SIZE, NULL)) {
+                       dev_info(hdev->dev,
+                               "device is not idle (mask %#llx %#llx) after soft reset, performing hard reset",
+                               idle_mask[0], idle_mask[1]);
+                       hl_device_reset(hdev, true, false);
+               }
+       }
 }
 
 void hl_hpriv_get(struct hl_fpriv *hpriv)
@@ -106,22 +122,6 @@ static int hl_device_release(struct inode *inode, struct file *filp)
        hl_cb_mgr_fini(hdev, &hpriv->cb_mgr);
        hl_ctx_mgr_fini(hdev, &hpriv->ctx_mgr);
 
-       if (hdev->reset_upon_device_release) {
-               u64 idle_mask[HL_BUSY_ENGINES_MASK_EXT_SIZE] = {0};
-
-               /* We try soft reset first */
-               hl_device_reset(hdev, false, false);
-
-               /* If device is not idle perform hard reset */
-               if (!hdev->asic_funcs->is_device_idle(hdev, idle_mask,
-                               HL_BUSY_ENGINES_MASK_EXT_SIZE, NULL)) {
-                       dev_info(hdev->dev,
-                               "device is not idle (mask %#llx %#llx) after soft reset, performing hard reset",
-                               idle_mask[0], idle_mask[1]);
-                       hl_device_reset(hdev, true, false);
-               }
-       }
-
        hl_hpriv_put(hpriv);
 
        return 0;