From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Shay Agroskin <shayagr@amazon.com>,
        Arthur Kiyanovski <akiyano@amazon.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.10 25/43] net: ena: Fix error handling when calculating max IO queues number
Date:   Mon, 10 Jan 2022 08:23:22 +0100
Message-Id: <20220110071818.195583561@linuxfoundation.org>
In-Reply-To: <20220110071817.337619922@linuxfoundation.org>
References: <20220110071817.337619922@linuxfoundation.org>
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From: Arthur Kiyanovski <akiyano@amazon.com>

commit 5055dc0348b8b7c168e3296044bccd724e1ae6cd upstream.

The role of ena_calc_max_io_queue_num() is to return the number
of queues supported by the device, which means the return value
should be >=0.

The function that calls ena_calc_max_io_queue_num(), checks
the return value. If it is 0, it means the device reported
it supports 0 IO queues. This case is considered an error
and is handled by the calling function accordingly.

However the current implementation of ena_calc_max_io_queue_num()
is wrong, since when it detects the device supports 0 IO queues,
it returns -EFAULT.

In such a case the calling function doesn't detect the error,
and therefore doesn't handle it.

This commit changes ena_calc_max_io_queue_num() to return 0
in case the device reported it supports 0 queues, allowing the
calling function to properly handle the error case.

Fixes: 736ce3f414cc ("net: ena: make ethtool -l show correct max number of queues")
Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/amazon/ena/ena_netdev.c |    4 ----
 1 file changed, 4 deletions(-)

--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -3927,10 +3927,6 @@ static u32 ena_calc_max_io_queue_num(str
 	max_num_io_queues = min_t(u32, max_num_io_queues, io_tx_cq_num);
 	/* 1 IRQ for for mgmnt and 1 IRQs for each IO direction */
 	max_num_io_queues = min_t(u32, max_num_io_queues, pci_msix_vec_count(pdev) - 1);
-	if (unlikely(!max_num_io_queues)) {
-		dev_err(&pdev->dev, "The device doesn't have io queues\n");
-		return -EFAULT;
-	}
 
 	return max_num_io_queues;
 }