[Intel-wired-lan] [net PATCH] i40e/i40evf: avoid mutex re-init

[Jesse Brandeburg]

If the driver were to happen to have a mutex held while
the i40e_init_adminq call was called, the init_adminq might
inadvertently call mutex_init on a lock that was held
which is a violation of the calling semantics.

Fix this by avoiding adminq.c code allocating/freeing this memory, and
then do the same work only once in probe/remove.

Testing Hints (Required if no HSD): for VF, load i40evf in bare metal
and echo 32 > sriov_numvfs; echo 0 > sriov_numvfs in a loop.  Yes this
is a horrible thing to do.

Reported-by: Stefan Assmann <sassmann at redhat.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg at intel.com>
Change-ID: Ida263c51b34e195252179e7e5e400d73a99be7a2
---
 drivers/net/ethernet/intel/i40e/i40e_main.c     | 10 ++++++++++
 drivers/net/ethernet/intel/i40evf/i40evf_main.c | 10 ++++++++++
 2 files changed, 20 insertions(+)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 36645828..67cc0a8 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -10457,6 +10457,12 @@ static int i40e_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	/* set up a default setting for link flow control */
 	pf->hw.fc.requested_mode = I40E_FC_NONE;
 
+	/* set up the locks for the AQ, do this only once in probe
+	 * and destroy them only once in remove
+	 */
+	mutex_init(&hw->aq.asq_mutex);
+	mutex_init(&hw->aq.arq_mutex);
+
 	err = i40e_init_adminq(hw);
 	if (err) {
 		if (err == I40E_ERR_FIRMWARE_API_VERSION)
@@ -10917,6 +10923,10 @@ static void i40e_remove(struct pci_dev *pdev)
 			 "Failed to destroy the Admin Queue resources: %d\n",
 			 ret_code);
 
+	/* destroy the locks only once, here */
+	mutex_destroy(&hw->aq.arq_mutex);
+	mutex_destroy(&hw->aq.asq_mutex);
+
 	/* Clear all dynamic memory lists of rings, q_vectors, and VSIs */
 	i40e_clear_interrupt_scheme(pf);
 	for (i = 0; i < pf->num_alloc_vsi; i++) {
diff --git a/drivers/net/ethernet/intel/i40evf/i40evf_main.c b/drivers/net/ethernet/intel/i40evf/i40evf_main.c
index 7e207ed..6da6cd7 100644
--- a/drivers/net/ethernet/intel/i40evf/i40evf_main.c
+++ b/drivers/net/ethernet/intel/i40evf/i40evf_main.c
@@ -2652,6 +2652,12 @@ static int i40evf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	hw->bus.device = PCI_SLOT(pdev->devfn);
 	hw->bus.func = PCI_FUNC(pdev->devfn);
 
+	/* set up the locks for the AQ, do this only once in probe
+	 * and destroy them only once in remove
+	 */
+	mutex_init(&hw->aq.asq_mutex);
+	mutex_init(&hw->aq.arq_mutex);
+
 	INIT_LIST_HEAD(&adapter->mac_filter_list);
 	INIT_LIST_HEAD(&adapter->vlan_filter_list);
 
@@ -2808,6 +2814,10 @@ static void i40evf_remove(struct pci_dev *pdev)
 	if (hw->aq.asq.count)
 		i40evf_shutdown_adminq(hw);
 
+	/* destroy the locks only once, here */
+	mutex_destroy(&hw->aq.arq_mutex);
+	mutex_destroy(&hw->aq.asq_mutex);
+
 	iounmap(hw->hw_addr);
 	pci_release_regions(pdev);
 
-- 
1.8.3.1