From: Xie He <xie.he.0141@gmail.com>
To: Krzysztof Halasa <khc@pm.waw.pl>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Xie He <xie.he.0141@gmail.com>, Martin Schiller <ms@dev.tdt.de>
Subject: [PATCH net v2] drivers/net/wan/hdlc_fr: Add needed_headroom for PVC devices
Date: Wed, 2 Sep 2020 17:06:58 -0700 [thread overview]
Message-ID: <20200903000658.89944-1-xie.he.0141@gmail.com> (raw)
PVC devices are virtual devices in this driver stacked on top of the
actual HDLC device. They are the devices normal users would use.
PVC devices have two types: normal PVC devices and Ethernet-emulating
PVC devices.
When transmitting data with PVC devices, the ndo_start_xmit function
will prepend a header of 4 or 10 bytes. Currently this driver requests
this headroom to be reserved for normal PVC devices by setting their
hard_header_len to 10. However, this does not work when these devices
are used with AF_PACKET/RAW sockets. Also, this driver does not request
this headroom for Ethernet-emulating PVC devices (but deals with this
problem by reallocating the skb when needed, which is not optimal).
This patch replaces hard_header_len with needed_headroom, and set
needed_headroom for Ethernet-emulating PVC devices, too. This makes
the driver to request headroom for all PVC devices in all cases.
Cc: Krzysztof Halasa <khc@pm.waw.pl>
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
---
Change from v1:
English language fix for the commit message.
Changed "Ethernet-emulated" to "Ethernet-emulating" because the device
is emulating an Ethernet device, rather than being emulated by an
Ethernet device.
I'm sorry for my poor English.
---
drivers/net/wan/hdlc_fr.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c
index 9acad651ea1f..12b35404cd8e 100644
--- a/drivers/net/wan/hdlc_fr.c
+++ b/drivers/net/wan/hdlc_fr.c
@@ -1041,7 +1041,7 @@ static void pvc_setup(struct net_device *dev)
{
dev->type = ARPHRD_DLCI;
dev->flags = IFF_POINTOPOINT;
- dev->hard_header_len = 10;
+ dev->hard_header_len = 0;
dev->addr_len = 2;
netif_keep_dst(dev);
}
@@ -1093,6 +1093,7 @@ static int fr_add_pvc(struct net_device *frad, unsigned int dlci, int type)
dev->mtu = HDLC_MAX_MTU;
dev->min_mtu = 68;
dev->max_mtu = HDLC_MAX_MTU;
+ dev->needed_headroom = 10;
dev->priv_flags |= IFF_NO_QUEUE;
dev->ml_priv = pvc;
--
2.25.1
next reply other threads:[~2020-09-03 0:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 0:06 Xie He [this message]
2020-09-04 22:14 ` [PATCH net v2] drivers/net/wan/hdlc_fr: Add needed_headroom for PVC devices Jakub Kicinski
2020-09-05 1:28 ` Xie He
2020-09-05 1:57 ` Xie He
2020-09-05 4:36 ` Jakub Kicinski
2020-09-05 9:20 ` Xie He
2020-09-14 5:26 ` Krzysztof Hałasa
2020-09-14 6:18 ` Xie He
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