Revision ac3a0c8472969a03c0496ae774b3a29eb26c8d5a authored by Linus Torvalds on 01 August 2020, 23:47:24 UTC, committed by Linus Torvalds on 01 August 2020, 23:47:24 UTC
Pull networking fixes from David Miller:

 1) Encap offset calculation is incorrect in esp6, from Sabrina Dubroca.

 2) Better parameter validation in pfkey_dump(), from Mark Salyzyn.

 3) Fix several clang issues on powerpc in selftests, from Tanner Love.

 4) cmsghdr_from_user_compat_to_kern() uses the wrong length, from Al
    Viro.

 5) Out of bounds access in mlx5e driver, from Raed Salem.

 6) Fix transfer buffer memleak in lan78xx, from Johan Havold.

 7) RCU fixups in rhashtable, from Herbert Xu.

 8) Fix ipv6 nexthop refcnt leak, from Xiyu Yang.

 9) vxlan FDB dump must be done under RCU, from Ido Schimmel.

10) Fix use after free in mlxsw, from Ido Schimmel.

11) Fix map leak in HASH_OF_MAPS bpf code, from Andrii Nakryiko.

12) Fix bug in mac80211 Tx ack status reporting, from Vasanthakumar
    Thiagarajan.

13) Fix memory leaks in IPV6_ADDRFORM code, from Cong Wang.

14) Fix bpf program reference count leaks in mlx5 during
    mlx5e_alloc_rq(), from Xin Xiong.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (86 commits)
  vxlan: fix memleak of fdb
  rds: Prevent kernel-infoleak in rds_notify_queue_get()
  net/sched: The error lable position is corrected in ct_init_module
  net/mlx5e: fix bpf_prog reference count leaks in mlx5e_alloc_rq
  net/mlx5e: E-Switch, Specify flow_source for rule with no in_port
  net/mlx5e: E-Switch, Add misc bit when misc fields changed for mirroring
  net/mlx5e: CT: Support restore ipv6 tunnel
  net: gemini: Fix missing clk_disable_unprepare() in error path of gemini_ethernet_port_probe()
  ionic: unlock queue mutex in error path
  atm: fix atm_dev refcnt leaks in atmtcp_remove_persistent
  net: ethernet: mtk_eth_soc: fix MTU warnings
  net: nixge: fix potential memory leak in nixge_probe()
  devlink: ignore -EOPNOTSUPP errors on dumpit
  rxrpc: Fix race between recvmsg and sendmsg on immediate call failure
  MAINTAINERS: Replace Thor Thayer as Altera Triple Speed Ethernet maintainer
  selftests/bpf: fix netdevsim trap_flow_action_cookie read
  ipv6: fix memory leaks on IPV6_ADDRFORM path
  net/bpfilter: Initialize pos in __bpfilter_process_sockopt
  igb: reinit_locked() should be called with rtnl_lock
  e1000e: continue to init PHY even when failed to disable ULP
  ...
2 parent s 0ae3495 + fda2ec6
Raw File
ide-tape.rst
===============================
IDE ATAPI streaming tape driver
===============================

This driver is a part of the Linux ide driver.

The driver, in co-operation with ide.c, basically traverses the
request-list for the block device interface. The character device
interface, on the other hand, creates new requests, adds them
to the request-list of the block device, and waits for their completion.

The block device major and minor numbers are determined from the
tape's relative position in the ide interfaces, as explained in ide.c.

The character device interface consists of the following devices::

  ht0		major 37, minor 0	first  IDE tape, rewind on close.
  ht1		major 37, minor 1	second IDE tape, rewind on close.
  ...
  nht0		major 37, minor 128	first  IDE tape, no rewind on close.
  nht1		major 37, minor 129	second IDE tape, no rewind on close.
  ...

The general magnetic tape commands compatible interface, as defined by
include/linux/mtio.h, is accessible through the character device.

General ide driver configuration options, such as the interrupt-unmask
flag, can be configured by issuing an ioctl to the block device interface,
as any other ide device.

Our own ide-tape ioctl's can be issued to either the block device or
the character device interface.

Maximal throughput with minimal bus load will usually be achieved in the
following scenario:

     1.	ide-tape is operating in the pipelined operation mode.
     2.	No buffering is performed by the user backup program.

Testing was done with a 2 GB CONNER CTMA 4000 IDE ATAPI Streaming Tape Drive.

Here are some words from the first releases of hd.c, which are quoted
in ide.c and apply here as well:

* Special care is recommended.  Have Fun!

Possible improvements
=====================

1. Support for the ATAPI overlap protocol.

In order to maximize bus throughput, we currently use the DSC
overlap method which enables ide.c to service requests from the
other device while the tape is busy executing a command. The
DSC overlap method involves polling the tape's status register
for the DSC bit, and servicing the other device while the tape
isn't ready.

In the current QIC development standard (December 1995),
it is recommended that new tape drives will *in addition*
implement the ATAPI overlap protocol, which is used for the
same purpose - efficient use of the IDE bus, but is interrupt
driven and thus has much less CPU overhead.

ATAPI overlap is likely to be supported in most new ATAPI
devices, including new ATAPI cdroms, and thus provides us
a method by which we can achieve higher throughput when
sharing a (fast) ATA-2 disk with any (slow) new ATAPI device.
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