s390/pci: handle FH state mismatch only on disable

Instead of always treating CLP_RC_SETPCIFN_ALRDY as success and blindly
updating the function handle restrict this special handling to the
disable case by moving it into zpci_disable_device() and still treating
it as an error while also updating the function handle such that
a subsequent zpci_disable_device() succeeds or the caller can ignore the
error when aborting is not an option such as for zPCI event 0x304.
Also print this occurrence to the log such that an admin can tell why
a disable operation returned an error.

A mismatch between the state of the underlying device and our view of it
can naturally happen when the device suddenly enters the error state but
we haven't gotten the error notification yet, it must not happen on
enable though.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 4eafa8160184..6be5ee320194 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -674,12 +674,25 @@ out:
 
 int zpci_disable_device(struct zpci_dev *zdev)
 {
+	int cc, rc = 0;
+
 	zpci_dma_exit_device(zdev);
 	/*
 	 * The zPCI function may already be disabled by the platform, this is
 	 * detected in clp_disable_fh() which becomes a no-op.
 	 */
-	return clp_disable_fh(zdev) ? -EIO : 0;
+	cc = clp_disable_fh(zdev);
+	if (cc == CLP_RC_SETPCIFN_ALRDY) {
+		pr_info("Disabling PCI function %08x had no effect as it was already disabled\n",
+			zdev->fid);
+		/* Function is already disabled - update handle */
+		rc = clp_refresh_fh(zdev->fid);
+		if (!rc)
+			rc = -EINVAL;
+	} else if (cc) {
+		rc = -EIO;
+	}
+	return rc;
 }
 
 /**