On Tue, Dec 06, 2022 at 10:13:21AM +0800, Longpeng(Mike) wrote:
From: Longpeng <[email protected]>
1. We should not set status to 0 when invoking vp_vdpa_set_status(),
trigger a warning in that case.
2. The driver MUST wait for a read of device_status to return 0 before
reinitializing the device. But we also don't want to keep us in an
infinite loop forever, so wait for 5s if we try to reset the device.
Signed-off-by: Longpeng <[email protected]>
---
Changes v1->v2:
- use WARN_ON instead of BUG_ON. [Stefano]
- use "warning + failed" instead of "infinite loop". [Jason, Stefano]
- use usleep_range instead of msleep (checkpatch). [Longpeng]
---
drivers/vdpa/virtio_pci/vp_vdpa.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c
b/drivers/vdpa/virtio_pci/vp_vdpa.c
index 13701c2a1963..a2d3b13ac646 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -214,6 +214,9 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8
status)
struct virtio_pci_modern_device *mdev = vp_vdpa_to_mdev(vp_vdpa);
u8 s = vp_vdpa_get_status(vdpa);
+ /* We should never be setting status to 0. */
+ WARN_ON(status == 0);
+
if (status & VIRTIO_CONFIG_S_DRIVER_OK &&
!(s & VIRTIO_CONFIG_S_DRIVER_OK)) {
vp_vdpa_request_irq(vp_vdpa);
@@ -222,14 +225,33 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa,
u8 status)
vp_modern_set_status(mdev, status);
}
+#define VP_VDPA_RESET_TMOUT_MS 5000 /* 5s */
What about moving this define on top of this file?
Near the other macro.
And I would use TIMEOUT entirely.
+
static int vp_vdpa_reset(struct vdpa_device *vdpa, bool clear)
{
struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
struct virtio_pci_modern_device *mdev = vp_vdpa_to_mdev(vp_vdpa);
u8 s = vp_vdpa_get_status(vdpa);
+ unsigned long timeout;
vp_modern_set_status(mdev, 0);
+ /*
+ * As the virtio v1.1 spec (4.1.4.3.2) says: After writing 0 to
I think we can refer to the lates v1.2 (the section should be the same).
+ * device_status, the driver MUST wait for a read of device_status
+ * to return 0 before reinitializing the device.
+ * To avoid keep us here forever, we only wait for 5 seconds.
+ */
+ timeout = jiffies + msecs_to_jiffies(VP_VDPA_RESET_TMOUT_MS);
+ while (vp_modern_get_status(mdev)) {
+ usleep_range(1000, 1500);
+ if (time_after(jiffies, timeout)) {
+ dev_err(&mdev->pci_dev->dev,
+ "vp_vdpa: fail to reset device\n");
+ return -ETIMEDOUT;
+ }
+ }
+
if (s & VIRTIO_CONFIG_S_DRIVER_OK)
vp_vdpa_free_irq(vp_vdpa);
--
2.23.0
The rest LGTM!
Thanks,
Stefano
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