During an eeh event when the cxl card is fenced and card sysfs attr
perst_reloads_same_image is set following warning message is seen in the
kernel logs:
[ 60.622727] Adapter context unlocked with 0 active contexts
[ 60.622762] ------------[ cut here ]------------
[ 60.622771] WARNING: CPU: 12 PID: 627 at
../drivers/misc/cxl/main.c:325 cxl_adapter_context_unlock+0x60/0x80 [cxl]
Even though this warning is harmless, it clutters the kernel log
during an eeh event. This warning is triggered as the EEH callback
cxl_pci_error_detected doesn't obtain a context-lock before forcibly
detaching all active context and when context-lock is released during
call to cxl_configure_adapter from cxl_pci_slot_reset, a warning in
cxl_adapter_context_unlock is triggered.
To fix this warning, we acquire the adapter context-lock via
cxl_adapter_context_lock() in the eeh callback
cxl_pci_error_detected() once all the virtual AFU PHBs are notified
and their contexts detached. After the EEH flow concludes with
call to cxl_pci_resume() the context-lock is released with a call to
cxl_adapter_context_unlock() just before notifying all virtual AFU
PHBs to resume so that they can re-activate any contexts if needed.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 70b565bbdb91("cxl: Prevent adapter reset if an active context exists")
Reported-by: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx>
Signed-off-by: Vaibhav Jain <vaibhav@xxxxxxxxxxxxxxxxxx>
---
Change-Log:
v2..v3
- As discussed with Fred removed function
cxl_adapter_context_force_lock() which may potentially expose the code
to deadlock in the future.
- Other details of changes in cxl_pci_error_detected() to fix an
earlier issue of eeh callbacks not being passed on to all slices, is
being reworked as a separate patch.
v2..v1
- Moved the call to cxl_adapter_context_force_lock() from
cxl_pci_error_detected() to cxl_remove. (Fred)
---
drivers/misc/cxl/pci.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index b27ea98..1e98245 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -1496,8 +1496,6 @@ static int cxl_configure_adapter(struct cxl *adapter, struct pci_dev *dev)
if ((rc = cxl_native_register_psl_err_irq(adapter)))
goto err;
- /* Release the context lock as adapter is configured */
- cxl_adapter_context_unlock(adapter);
return 0;
err:
@@ -1596,6 +1594,9 @@ static struct cxl *cxl_pci_init_adapter(struct pci_dev *dev)
if ((rc = cxl_sysfs_adapter_add(adapter)))
goto err_put1;
+ /* Release the context lock as adapter is configured */
+ cxl_adapter_context_unlock(adapter);
+
return adapter;
err_put1:
@@ -1895,6 +1896,13 @@ static pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev,
cxl_ops->afu_deactivate_mode(afu, afu->current_mode);
pci_deconfigure_afu(afu);
}
+
+ /* should take the context lock here */
+ if (cxl_adapter_context_lock(adapter) != 0)
+ dev_warn(&adapter->dev,
+ "Couldn't take context lock with %d active-contexts\n",
+ atomic_read(&adapter->contexts_num));
+
cxl_deconfigure_adapter(adapter);
return result;
@@ -1977,6 +1985,9 @@ static void cxl_pci_resume(struct pci_dev *pdev)
struct pci_dev *afu_dev;
int i;
+ /* Unlock context activation for the adapter */
+ cxl_adapter_context_unlock(adapter);
+
/* Everything is back now. Drivers should restart work now.
* This is not the place to be checking if everything came back up
* properly, because there's no return value: do that in slot_reset.
--
2.9.3