netdev - [RESEND PATCH] ixgbe: Don't call kmap() on page allocated with GFP

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Date:   Thu, 15 Sep 2022 14:40:12 +0200
From:   "Fabio M. De Francesco" <fmdefrancesco@...il.com>
To:     Jesse Brandeburg <jesse.brandeburg@...el.com>,
        Tony Nguyen <anthony.l.nguyen@...el.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        John Fastabend <john.fastabend@...il.com>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, bpf@...r.kernel.org,
        linux-hwmon@...r.kernel.org
Cc:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Alexander Duyck <alexander.duyck@...il.com>,
        Gurucharan <gurucharanx.g@...el.com>
Subject: [RESEND PATCH] ixgbe: Don't call kmap() on page allocated with GFP_ATOMIC

Pages allocated with GFP_ATOMIC cannot come from Highmem. This is why
there is no need to call kmap() on them.

Therefore, don't call kmap() on rx_buffer->page() and instead use a
plain page_address() to get the kernel address.

Suggested-by: Ira Weiny <ira.weiny@...el.com>
Suggested-by: Alexander Duyck <alexander.duyck@...il.com>
Reviewed-by: Ira Weiny <ira.weiny@...el.com>
Reviewed-by: Alexander Duyck <alexander.duyck@...il.com>
Tested-by: Gurucharan <gurucharanx.g@...el.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@...il.com>
---

I send again this patch because it was submitted more than two months ago,
Monday 4th July 2022, but for one or more (good?) reasons it has not yet
reached Linus' tree. In the meantime I am also forwarding two "Reviewed-by"
and one "Tested-by" tags (thanks a lot to Ira, Alexander, Gurucharan).
Obviously I have not made any changes to the code.

 drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
index 04f453eabef6..cb5c707538a5 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
@@ -1964,15 +1964,13 @@ static bool ixgbe_check_lbtest_frame(struct ixgbe_rx_buffer *rx_buffer,
 
 	frame_size >>= 1;
 
-	data = kmap(rx_buffer->page) + rx_buffer->page_offset;
+	data = page_address(rx_buffer->page) + rx_buffer->page_offset;
 
 	if (data[3] != 0xFF ||
 	    data[frame_size + 10] != 0xBE ||
 	    data[frame_size + 12] != 0xAF)
 		match = false;
 
-	kunmap(rx_buffer->page);
-
 	return match;
 }
 
-- 
2.37.2