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Commit 30424e38 authored by Sam Bobroff's avatar Sam Bobroff Committed by Michael Ellerman
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powerpc/eeh: Clean up pci_ers_result handling 



As EEH event handling progresses, a cumulative result of type
pci_ers_result is built up by (some of) the eeh_report_*() functions
using either:
	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
or:
	if ((*res == PCI_ERS_RESULT_NONE) ||
	    (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
	if (*res == PCI_ERS_RESULT_DISCONNECT &&
	    rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
(Where *res is the accumulator.)

However, the intent is not immediately clear and the result in some
situations is order dependent.

Address this by assigning a priority to each result value, and always
merging to the highest priority. This renders the intent clear, and
provides a stable value for all orderings.

Signed-off-by: default avatarSam Bobroff <sbobroff@linux.ibm.com>
[mpe: Minor formatting (clang-format)]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 2eae39f2

arch/powerpc/kernel/eeh_driver.c

+32 −10
Original line number Diff line number Diff line
@@ -39,6 +39,35 @@ struct eeh_rmv_data { 
	int removed;

};



static int eeh_result_priority(enum pci_ers_result result)

{

	switch (result) {

	case PCI_ERS_RESULT_NONE:

		return 1;

	case PCI_ERS_RESULT_NO_AER_DRIVER:

		return 2;

	case PCI_ERS_RESULT_RECOVERED:

		return 3;

	case PCI_ERS_RESULT_CAN_RECOVER:

		return 4;

	case PCI_ERS_RESULT_DISCONNECT:

		return 5;

	case PCI_ERS_RESULT_NEED_RESET:

		return 6;

	default:

		WARN_ONCE(1, "Unknown pci_ers_result value: %d\n", (int)result);

		return 0;

	}

};



static enum pci_ers_result pci_ers_merge_result(enum pci_ers_result old,

						enum pci_ers_result new)

{

	if (eeh_result_priority(new) > eeh_result_priority(old))

		return new;

	return old;

}



/**

 * eeh_pcid_get - Get the PCI device driver

 * @pdev: PCI device
@@ -206,9 +235,7 @@ static void *eeh_report_error(struct eeh_dev *edev, void *userdata) 


	rc = driver->err_handler->error_detected(dev, pci_channel_io_frozen);



	/* A driver that needs a reset trumps all others */

	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;

	if (*res == PCI_ERS_RESULT_NONE) *res = rc;

	*res = pci_ers_merge_result(*res, rc);



	edev->in_error = true;

	pci_uevent_ers(dev, PCI_ERS_RESULT_NONE);
@@ -249,9 +276,7 @@ static void *eeh_report_mmio_enabled(struct eeh_dev *edev, void *userdata) 


	rc = driver->err_handler->mmio_enabled(dev);



	/* A driver that needs a reset trumps all others */

	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;

	if (*res == PCI_ERS_RESULT_NONE) *res = rc;

	*res = pci_ers_merge_result(*res, rc);



out:

	eeh_pcid_put(dev);
@@ -294,10 +319,7 @@ static void *eeh_report_reset(struct eeh_dev *edev, void *userdata) 
		goto out;



	rc = driver->err_handler->slot_reset(dev);

	if ((*res == PCI_ERS_RESULT_NONE) ||

	    (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;

	if (*res == PCI_ERS_RESULT_DISCONNECT &&

	     rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;

	*res = pci_ers_merge_result(*res, rc);



out:

	eeh_pcid_put(dev);