From: Niklas Schnelle <schnelle@linux.ibm.com>
Date: Thu, 22 Jul 2021 12:38:29 +0200
Subject: s390/pci: handle FH state mismatch only on disable
Git-commit: 8256adda1f44ea1ec763711aefcd25f8c0cf93f3
Patch-mainline: v5.15-rc1
References: jsc#PED-592

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>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 arch/s390/include/asm/pci.h |    1 +
 arch/s390/pci/pci.c         |   15 ++++++++++++++-
 arch/s390/pci/pci_clp.c     |    6 +-----
 3 files changed, 16 insertions(+), 6 deletions(-)

--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -219,6 +219,7 @@ int clp_query_pci_fn(struct zpci_dev *zd
 int clp_enable_fh(struct zpci_dev *, u8);
 int clp_disable_fh(struct zpci_dev *);
 int clp_get_state(u32 fid, enum zpci_state *state);
+int clp_refresh_fh(u32 fid);
 
 /* UID */
 void update_uid_checking(bool new);
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -680,12 +680,25 @@ 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;
 }
 
 /**
--- a/arch/s390/pci/pci_clp.c
+++ b/arch/s390/pci/pci_clp.c
@@ -212,7 +212,6 @@ out:
 	return rc;
 }
 
-static int clp_refresh_fh(u32 fid);
 /**
  * clp_set_pci_fn() - Execute a command on a PCI function
  * @zdev: Function that will be affected
@@ -251,9 +250,6 @@ static int clp_set_pci_fn(struct zpci_de
 
 	if (!rc && rrb->response.hdr.rsp == CLP_RC_OK) {
 		zdev->fh = rrb->response.fh;
-	} else if (!rc && rrb->response.hdr.rsp == CLP_RC_SETPCIFN_ALRDY) {
-		/* Function is already in desired state - update handle */
-		rc = clp_refresh_fh(zdev->fid);
 	} else {
 		zpci_err("Set PCI FN:\n");
 		zpci_err_clp(rrb->response.hdr.rsp, rc);
@@ -409,7 +405,7 @@ static void __clp_refresh_fh(struct clp_
 /*
  * Refresh the function handle of the function matching @fid
  */
-static int clp_refresh_fh(u32 fid)
+int clp_refresh_fh(u32 fid)
 {
 	struct clp_req_rsp_list_pci *rrb;
 	int rc;