linux-kernel - [PATCH 4.4 021/192] [PATCH 021/135] fm10k: reset max_queues on init_hw

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Message-Id: <20160912152159.798170575@linuxfoundation.org>
Date:   Mon, 12 Sep 2016 18:58:50 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jacob Keller <jacob.e.keller@...el.com>,
        Bruce Allan <bruce.w.allan@...el.com>,
        Krishneil Singh <Krishneil.k.singh@...el.com>,
        Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.4 021/192] [PATCH 021/135] fm10k: reset max_queues on init_hw_vf failure

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 0e8d5b5975401c83641efd5d4595e6cdbe9e9e2f ]

VF drivers must detect how many queues are available. Previously, the
driver assumed that each VF has at minimum 1 queue. This assumption is
incorrect, since it is possible that the PF has not yet assigned the
queues to the VF by the time the VF checks. To resolve this, we added a
check first to ensure that the first queue is infact owned by the VF at
init_hw_vf time. However, the code flow did not reset hw->mac.max_queues
to 0. In some cases, such as during reinit flows, we call init_hw_vf
without clearing the previous value of hw->mac.max_queues. Due to this,
when init_hw_vf errors out, if its error code is not properly handled
the VF driver may still believe it has queues which no longer belong to
it. Fix this by clearing the hw->mac.max_queues on exit due to errors.

Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
Reviewed-by: Bruce Allan <bruce.w.allan@...el.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/net/ethernet/intel/fm10k/fm10k_vf.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

--- a/drivers/net/ethernet/intel/fm10k/fm10k_vf.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_vf.c
@@ -105,8 +105,10 @@ static s32 fm10k_init_hw_vf(struct fm10k
 
 	/* verify we have at least 1 queue */
 	if (!~fm10k_read_reg(hw, FM10K_TXQCTL(0)) ||
-	    !~fm10k_read_reg(hw, FM10K_RXQCTL(0)))
-		return FM10K_ERR_NO_RESOURCES;
+	    !~fm10k_read_reg(hw, FM10K_RXQCTL(0))) {
+		err = FM10K_ERR_NO_RESOURCES;
+		goto reset_max_queues;
+	}
 
 	/* determine how many queues we have */
 	for (i = 1; tqdloc0 && (i < FM10K_MAX_QUEUES_POOL); i++) {
@@ -124,7 +126,7 @@ static s32 fm10k_init_hw_vf(struct fm10k
 	/* shut down queues we own and reset DMA configuration */
 	err = fm10k_disable_queues_generic(hw, i);
 	if (err)
-		return err;
+		goto reset_max_queues;
 
 	/* record maximum queue count */
 	hw->mac.max_queues = i;
@@ -134,6 +136,11 @@ static s32 fm10k_init_hw_vf(struct fm10k
 			       FM10K_TXQCTL_VID_MASK) >> FM10K_TXQCTL_VID_SHIFT;
 
 	return 0;
+
+reset_max_queues:
+	hw->mac.max_queues = 0;
+
+	return err;
 }
 
 /* This structure defines the attibutes to be parsed below */