[PATCH] ibmvnic: Fix possibly uninitialized old_num_tx_queues variable warning.

GCC 7.5 reports:
../drivers/net/ethernet/ibm/ibmvnic.c: In function 'ibmvnic_reset_init':
../drivers/net/ethernet/ibm/ibmvnic.c:5373:51: warning: 'old_num_tx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]
../drivers/net/ethernet/ibm/ibmvnic.c:5373:6: warning: 'old_num_rx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]

The variable is initialized only if(reset) and used only if(reset &&
something) so this is a false positive. However, there is no reason to
not initialize the variables unconditionally avoiding the warning.

Fixes: 635e442f4a48 ("ibmvnic: merge ibmvnic_reset_init and ibmvnic_init")
Signed-off-by: Michal Suchanek <redacted>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 118a4bd3f877..3bad762083c5 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c

@@ -5219,16 +5219,14 @@ static int ibmvnic_reset_init(struct ibmvnic_adapter *adapter, bool reset)
 {
 	struct device *dev = &adapter->vdev->dev;
 	unsigned long timeout = msecs_to_jiffies(20000);
-	u64 old_num_rx_queues, old_num_tx_queues;
+	u64 old_num_rx_queues = adapter->req_rx_queues;
+	u64 old_num_tx_queues = adapter->req_tx_queues;
 	int rc;
 
 	adapter->from_passive_init = false;
 
-	if (reset) {
-		old_num_rx_queues = adapter->req_rx_queues;
-		old_num_tx_queues = adapter->req_tx_queues;
+	if (reset)
 		reinit_completion(&adapter->init_done);
-	}
 
 	adapter->init_done_rc = 0;
 	rc = ibmvnic_send_crq_init(adapter);

-- 
2.26.2

Michal Suchanek [msuchanek@suse.de] wrote:

GCC 7.5 reports:
../drivers/net/ethernet/ibm/ibmvnic.c: In function 'ibmvnic_reset_init':
../drivers/net/ethernet/ibm/ibmvnic.c:5373:51: warning: 'old_num_tx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]
../drivers/net/ethernet/ibm/ibmvnic.c:5373:6: warning: 'old_num_rx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]

The variable is initialized only if(reset) and used only if(reset &&
something) so this is a false positive. However, there is no reason to
not initialize the variables unconditionally avoiding the warning.

Yeah, its a false positive, but initializing doesn't hurt.

Fixes: 635e442f4a48 ("ibmvnic: merge ibmvnic_reset_init and ibmvnic_init")
Signed-off-by: Michal Suchanek <redacted>

Reviewed-by: Sukadev Bhattiprolu <redacted>

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Tue,  2 Mar 2021 20:47:47 +0100 you wrote:

GCC 7.5 reports:
../drivers/net/ethernet/ibm/ibmvnic.c: In function 'ibmvnic_reset_init':
../drivers/net/ethernet/ibm/ibmvnic.c:5373:51: warning: 'old_num_tx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]
../drivers/net/ethernet/ibm/ibmvnic.c:5373:6: warning: 'old_num_rx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]

The variable is initialized only if(reset) and used only if(reset &&
something) so this is a false positive. However, there is no reason to
not initialize the variables unconditionally avoiding the warning.

[...]

Here is the summary with links:
  - ibmvnic: Fix possibly uninitialized old_num_tx_queues variable warning.
    https://git.kernel.org/netdev/net/c/6881b07fdd24

You are awesome, thank you!
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