When uncorrectable error happens, AER driver and DPC driver interrupt
handlers likely call
pcie_do_recovery()
->pci_walk_bus()
->report_frozen_detected()
with pci_channel_io_frozen the same time.
If pci_dev_set_io_state() return true even if the original state is
pci_channel_io_frozen, that will cause AER or DPC handler re-enter
the error detecting and recovery procedure one after another.
The result is the recovery flow mixed between AER and DPC.
So simplify the pci_dev_set_io_state() function to only return true
when dev->error_state is really changed.
Signed-off-by: Ethan Zhao <haifeng.zhao@xxxxxxxxx>
Tested-by: Wen Jin <wen.jin@xxxxxxxxx>
Tested-by: Shanshan Zhang <ShanshanX.Zhang@xxxxxxxxx>
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
---
Changnes:
v2: revise description and code according to suggestion from Andy.
v3: change code to simpler.
v4: no change.
v5: no change.
v6: no change.
v7: changed based on Bjorn's code and truth table.
drivers/pci/pci.h | 53 ++++++++++++++++++-----------------------------
1 file changed, 20 insertions(+), 33 deletions(-)
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 455b32187abd..47af1ff2a286 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -354,44 +354,31 @@ struct pci_sriov {
*
* Must be called with device_lock held.
*
- * Returns true if state has been changed to the requested state.
+ * Returns true if state has been really changed to the requested state.
*/
static inline bool pci_dev_set_io_state(struct pci_dev *dev,
pci_channel_state_t new)
{
- bool changed = false;
-
device_lock_assert(&dev->dev);
- switch (new) {
- case pci_channel_io_perm_failure:
- switch (dev->error_state) {
- case pci_channel_io_frozen:
- case pci_channel_io_normal:
- case pci_channel_io_perm_failure:
- changed = true;
- break;
- }
- break;
- case pci_channel_io_frozen:
- switch (dev->error_state) {
- case pci_channel_io_frozen:
- case pci_channel_io_normal:
- changed = true;
- break;
- }
- break;
- case pci_channel_io_normal:
- switch (dev->error_state) {
- case pci_channel_io_frozen:
- case pci_channel_io_normal:
- changed = true;
- break;
- }
- break;
- }
- if (changed)
- dev->error_state = new;
- return changed;
+
+/*
+ * Truth table:
+ * requested new state
+ * current ------------------------------------------
+ * state normal frozen perm_failure
+ * ------------ + ------------- ------------- ------------
+ * normal | normal frozen perm_failure
+ * frozen | normal frozen perm_failure
+ * perm_failure | perm_failure* perm_failure* perm_failure
+ */
+
+ if (dev->error_state == pci_channel_io_perm_failure)
+ return false;
+ else if (dev->error_state == new)
+ return false;
+
+ dev->error_state = new;
+ return true;
}
static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused)
--
2.18.4
