Re: [PATCH v2 07/13] powerpc/eeh: Clean up pci_ers_result handling
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2018-06-01 15:40:54
Sam Bobroff [off-list ref] writes:
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: Sam Bobroff <redacted> --- ====== v1 -> v2: ====== * Added the value, and missing newline, to some WARN()s. * Improved name of merge_result() to pci_ers_merge_result(). * Adjusted the result priorities so that unknown doesn't overlap with _NONE.
These === markers seem to have confused patchwork, they ended up in the patch, and then git put them in the changelog. http://patchwork.ozlabs.org/patch/920194/ The usual format is just something like: v2 - Added the value, and missing newline, to some WARN()s. - Improved name of merge_result() to pci_ers_merge_result(). - Adjusted the result priorities so that unknown doesn't overlap with _NONE. cheers
quoted hunk ↗ jump to hunk
arch/powerpc/kernel/eeh_driver.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-)diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c index 188d15c4fe3a..2d3cac584899 100644 --- a/arch/powerpc/kernel/eeh_driver.c +++ b/arch/powerpc/kernel/eeh_driver.c@@ -39,6 +39,29 @@ 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 +229,7 @@ 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 +270,7 @@ 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 +313,7 @@ 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);-- 2.16.1.74.g9b0b1f47b