linux-kernel - [PATCH 3/5] iov: Fix sriov_enable exception handling path

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Date:	Tue, 27 Oct 2015 13:52:27 -0700
From:	Alexander Duyck <aduyck@...antis.com>
To:	bhelgaas@...gle.com
Cc:	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 3/5] iov: Fix sriov_enable exception handling path

>>From what I can tell there were several errors in the sriov_enable
exception handling path.  Below is a brief list of what I believe I am
fixing:

1.  If pcibios_enable_sriov failed, we returned without disabling SR-IOV on
    the device.
2.  If virtfn_add failed we didn't call pcibios_disable_sriov to undo
    pcibios_enable_sriov.
3.  We were resetting numvfs to 0 before a second had passed for the VFs to
    quiesce.
4.  Minor coding style issues for white space and for assignment in
    conditional check.

Beyond addressing these 4 issues there were also 2 other minor issues in
that retval was a redundant variable with rc, and j wasn't actually needed
as we could simply reverse the loop we were running when setting up i.  As
such I have updated the code to address those two items.

Signed-off-by: Alexander Duyck <aduyck@...antis.com>
---
 drivers/pci/iov.c |   31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 238950412de0..cecc242c1af0 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -231,13 +231,18 @@ static void virtfn_remove(struct pci_dev *dev, int id, int reset)
 
 int __weak pcibios_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
 {
-       return 0;
+	return 0;
+}
+
+int __weak pcibios_sriov_disable(struct pci_dev *pdev)
+{
+	return 0;
 }
 
 static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 {
 	int rc;
-	int i, j;
+	int i;
 	int nres;
 	u16 offset, stride, initial;
 	struct resource *res;
@@ -245,7 +250,6 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 	struct pci_sriov *iov = dev->sriov;
 	int bars = 0;
 	int bus;
-	int retval;
 
 	if (!nr_virtfn)
 		return 0;
@@ -322,10 +326,11 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 	if (nr_virtfn < initial)
 		initial = nr_virtfn;
 
-	if ((retval = pcibios_sriov_enable(dev, initial))) {
+	rc = pcibios_sriov_enable(dev, initial);
+	if (rc) {
 		dev_err(&dev->dev, "failure %d from pcibios_sriov_enable()\n",
-			retval);
-		return retval;
+			rc);
+		goto err_pcibios;
 	}
 
 	for (i = 0; i < initial; i++) {
@@ -340,25 +345,23 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 	return 0;
 
 failed:
-	for (j = 0; j < i; j++)
-		virtfn_remove(dev, j, 0);
+	while (i--)
+		virtfn_remove(dev, i, 0);
 
+	pcibios_sriov_disable(dev);
+err_pcibios:
 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 	pci_cfg_access_lock(dev);
 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
-	pci_iov_set_numvfs(dev, 0);
 	ssleep(1);
 	pci_cfg_access_unlock(dev);
 
 	if (iov->link != dev->devfn)
 		sysfs_remove_link(&dev->dev.kobj, "dep_link");
 
-	return rc;
-}
+	pci_iov_set_numvfs(dev, 0);
 
-int __weak pcibios_sriov_disable(struct pci_dev *pdev)
-{
-       return 0;
+	return rc;
 }
 
 static void sriov_disable(struct pci_dev *dev)

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