docs: networking: convert netdevices.txt to ReST

- add SPDX header;
- adjust title markup;
- mark lists as such;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 104 deletions

diff --git a/Documentation/networking/netdevices.txt b/Documentation/networking/netdevices.txt
deleted file mode 100644
index 7fec2061a334..000000000000
--- a/Documentation/networking/netdevices.txt
+++ /dev/null
@@ -1,104 +0,0 @@
-
-Network Devices, the Kernel, and You!
-
-
-Introduction
-============
-The following is a random collection of documentation regarding
-network devices.
-
-struct net_device allocation rules
-==================================
-Network device structures need to persist even after module is unloaded and
-must be allocated with alloc_netdev_mqs() and friends.
-If device has registered successfully, it will be freed on last use
-by free_netdev(). This is required to handle the pathologic case cleanly
-(example: rmmod mydriver </sys/class/net/myeth/mtu )
-
-alloc_netdev_mqs()/alloc_netdev() reserve extra space for driver
-private data which gets freed when the network device is freed. If
-separately allocated data is attached to the network device
-(netdev_priv(dev)) then it is up to the module exit handler to free that.
-
-MTU
-===
-Each network device has a Maximum Transfer Unit. The MTU does not
-include any link layer protocol overhead. Upper layer protocols must
-not pass a socket buffer (skb) to a device to transmit with more data
-than the mtu. The MTU does not include link layer header overhead, so
-for example on Ethernet if the standard MTU is 1500 bytes used, the
-actual skb will contain up to 1514 bytes because of the Ethernet
-header. Devices should allow for the 4 byte VLAN header as well.
-
-Segmentation Offload (GSO, TSO) is an exception to this rule.  The
-upper layer protocol may pass a large socket buffer to the device
-transmit routine, and the device will break that up into separate
-packets based on the current MTU.
-
-MTU is symmetrical and applies both to receive and transmit. A device
-must be able to receive at least the maximum size packet allowed by
-the MTU. A network device may use the MTU as mechanism to size receive
-buffers, but the device should allow packets with VLAN header. With
-standard Ethernet mtu of 1500 bytes, the device should allow up to
-1518 byte packets (1500 + 14 header + 4 tag).  The device may either:
-drop, truncate, or pass up oversize packets, but dropping oversize
-packets is preferred.
-
-
-struct net_device synchronization rules
-=======================================
-ndo_open:
-	Synchronization: rtnl_lock() semaphore.
-	Context: process
-
-ndo_stop:
-	Synchronization: rtnl_lock() semaphore.
-	Context: process
-	Note: netif_running() is guaranteed false
-
-ndo_do_ioctl:
-	Synchronization: rtnl_lock() semaphore.
-	Context: process
-
-ndo_get_stats:
-	Synchronization: dev_base_lock rwlock.
-	Context: nominally process, but don't sleep inside an rwlock
-
-ndo_start_xmit:
-	Synchronization: __netif_tx_lock spinlock.
-
-	When the driver sets NETIF_F_LLTX in dev->features this will be
-	called without holding netif_tx_lock. In this case the driver
-	has to lock by itself when needed.
-	The locking there should also properly protect against
-	set_rx_mode. WARNING: use of NETIF_F_LLTX is deprecated.
-	Don't use it for new drivers.
-
-	Context: Process with BHs disabled or BH (timer),
-	         will be called with interrupts disabled by netconsole.
-
-	Return codes: 
-	o NETDEV_TX_OK everything ok. 
-	o NETDEV_TX_BUSY Cannot transmit packet, try later 
-	  Usually a bug, means queue start/stop flow control is broken in
-	  the driver. Note: the driver must NOT put the skb in its DMA ring.
-
-ndo_tx_timeout:
-	Synchronization: netif_tx_lock spinlock; all TX queues frozen.
-	Context: BHs disabled
-	Notes: netif_queue_stopped() is guaranteed true
-
-ndo_set_rx_mode:
-	Synchronization: netif_addr_lock spinlock.
-	Context: BHs disabled
-
-struct napi_struct synchronization rules
-========================================
-napi->poll:
-	Synchronization: NAPI_STATE_SCHED bit in napi->state.  Device
-		driver's ndo_stop method will invoke napi_disable() on
-		all NAPI instances which will do a sleeping poll on the
-		NAPI_STATE_SCHED napi->state bit, waiting for all pending
-		NAPI activity to cease.
-	Context: softirq
-	         will be called with interrupts disabled by netconsole.