netdev - [PATCH V2 net 3/3] net: ena: Fix error handling when calculating max IO queues number

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Message-ID: <20220102073728.12242-4-akiyano@amazon.com>
Date:   Sun, 2 Jan 2022 07:37:28 +0000
From:   Arthur Kiyanovski <akiyano@...zon.com>
To:     David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, <netdev@...r.kernel.org>
CC:     Arthur Kiyanovski <akiyano@...zon.com>,
        "Woodhouse, David" <dwmw@...zon.com>,
        "Machulsky, Zorik" <zorik@...zon.com>,
        "Matushevsky, Alexander" <matua@...zon.com>,
        Saeed Bshara <saeedb@...zon.com>,
        "Wilson, Matt" <msw@...zon.com>,
        "Liguori, Anthony" <aliguori@...zon.com>,
        "Bshara, Nafea" <nafea@...zon.com>,
        "Belgazal, Netanel" <netanel@...zon.com>,
        "Saidi, Ali" <alisaidi@...zon.com>,
        "Herrenschmidt, Benjamin" <benh@...zon.com>,
        "Dagan, Noam" <ndagan@...zon.com>,
        "Agroskin, Shay" <shayagr@...zon.com>,
        "Arinzon, David" <darinzon@...zon.com>
Subject: [PATCH V2 net 3/3] net: ena: Fix error handling when calculating max IO queues number

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@...zon.com>
Signed-off-by: Arthur Kiyanovski <akiyano@...zon.com>
---
 drivers/net/ethernet/amazon/ena/ena_netdev.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index 52a8c60b7e29..c72f0c7ff4aa 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -4026,10 +4026,6 @@ static u32 ena_calc_max_io_queue_num(struct pci_dev *pdev,
 	max_num_io_queues = min_t(u32, max_num_io_queues, io_tx_cq_num);
 	/* 1 IRQ 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;
 }
-- 
2.32.0