This is a note to let you know that I've just added the patch titled
cxl: Force context lock during EEH flow
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cxl-force-context-lock-during-eeh-flow.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ea9a26d117cf0637c71d3e0076f4a124bf5859df Mon Sep 17 00:00:00 2001
From: Vaibhav Jain <vaibhav@xxxxxxxxxxxxxxxxxx>
Date: Thu, 27 Apr 2017 10:53:25 +0530
Subject: cxl: Force context lock during EEH flow
From: Vaibhav Jain <vaibhav@xxxxxxxxxxxxxxxxxx>
commit ea9a26d117cf0637c71d3e0076f4a124bf5859df upstream.
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:
Adapter context unlocked with 0 active contexts
------------[ cut here ]------------
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. The context-lock is released in
cxl_pci_slot_reset() after the adapter is successfully reconfigured
and before the we call the slot_reset callback on slice attached
device-drivers.
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>
Acked-by: Frederic Barrat <fbarrat@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Matthew R. Ochs <mrochs@xxxxxxxxxxxxxxxxxx>
Tested-by: Uma Krishnan <ukrishn@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/misc/cxl/pci.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -1496,8 +1496,6 @@ static int cxl_configure_adapter(struct
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(
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:
@@ -1893,6 +1894,13 @@ static pci_ers_result_t cxl_pci_error_de
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;
@@ -1911,6 +1919,13 @@ static pci_ers_result_t cxl_pci_slot_res
if (cxl_configure_adapter(adapter, pdev))
goto err;
+ /*
+ * Unlock context activation for the adapter. Ideally this should be
+ * done in cxl_pci_resume but cxlflash module tries to activate the
+ * master context as part of slot_reset callback.
+ */
+ cxl_adapter_context_unlock(adapter);
+
for (i = 0; i < adapter->slices; i++) {
afu = adapter->afu[i];
Patches currently in stable-queue which might be from vaibhav@xxxxxxxxxxxxxxxxxx are
queue-4.9/cxl-force-context-lock-during-eeh-flow.patch
queue-4.9/cxl-route-eeh-events-to-all-drivers-in-cxl_pci_error_detected.patch