linux-toradex.git/drivers/char/pcmcia, branch v4.4.29

tty: Remove ASYNC_CLOSING checks in open()/hangup() methods

2015-10-18T04:11:29+00:00

Since at least before 2.6.30, tty drivers that do not drop the tty lock
while closing cannot observe ASYNC_CLOSING set while holding the
tty lock; this includes the tty driver's open() and hangup() methods,
since the tty core calls these methods holding the tty lock.

For these drivers, waiting for ASYNC_CLOSING to clear while opening
is not required, since this condition cannot occur. Similarly, even
when the open() method drops and reacquires the tty lock after
blocking, ASYNC_CLOSING cannot be set (again, for drivers that
do not drop the tty lock while closing).

Now that tty port drivers no longer drop the tty lock while closing
(since 'tty: Remove tty_wait_until_sent_from_close()'), the same
conditions apply: waiting for ASYNC_CLOSING to clear while opening
is not required, nor is re-checking ASYNC_CLOSING after dropping and
reacquiring the tty lock while blocking (eg., in *_block_til_ready()).

Note: The ASYNC_CLOSING flag state is still maintained since several
bitrotting drivers use it for (dubious) other purposes.

Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'char-misc-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2015-06-26T21:51:15+00:00

Pull char/misc driver updates from Greg KH:
 "Here's the big char/misc driver pull request for 4.2-rc1.

  Lots of mei, extcon, coresight, uio, mic, and other driver updates in
  here.  Full details in the shortlog.  All of these have been in
  linux-next for some time with no reported problems"

* tag 'char-misc-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (176 commits)
  mei: me: wait for power gating exit confirmation
  mei: reset flow control on the last client disconnection
  MAINTAINERS: mei: add mei_cl_bus.h to maintained file list
  misc: sram: sort and clean up included headers
  misc: sram: move reserved block logic out of probe function
  misc: sram: add private struct device and virt_base members
  misc: sram: report correct SRAM pool size
  misc: sram: bump error message level on unclean driver unbinding
  misc: sram: fix device node reference leak on error
  misc: sram: fix enabled clock leak on error path
  misc: mic: Fix reported static checker warning
  misc: mic: Fix randconfig build error by including errno.h
  uio: pruss: Drop depends on ARCH_DAVINCI_DA850 from config
  uio: pruss: Add CONFIG_HAS_IOMEM dependence
  uio: pruss: Include 
  extcon: Redefine the unique id of supported external connectors without 'enum extcon' type
  char:xilinx_hwicap:buffer_icap - change 1/0 to true/false for bool type variable in function buffer_icap_set_configuration().
  Drivers: hv: vmbus: Allocate ring buffer memory in NUMA aware fashion
  parport: check exclusive access before register
  w1: use correct lock on error in w1_seq_show()
  ...

char:pcmcia:synclink_cs - Do not initialise statics to 0.

2015-05-31T21:38:21+00:00

Static variables are initialised to 0 by GCC.
Fixes the following checkpatch error:
ERROR: do not initialise statics to 0 or NULL
FILE: drivers/char/pcmcia/synclink_cs.c:440:
static bool break_on_load = 0;

Signed-off-by: Shailendra Verma 
Signed-off-by: Greg Kroah-Hartman

pcmcia: Convert dev_printk to dev_

2015-05-30T14:09:04+00:00

Reduce object size a little by using dev_
calls instead of dev_printk(KERN_.

Other miscellanea:

o Coalesce formats
o Realign arguments
o Use pr_cont instead of naked printk
  reorder test to use "%s\n"

Signed-off-by: Joe Perches 
Signed-off-by: Dominik Brodowski

char: synclink: Remove WARN_ON for bad port count

2014-07-10T23:07:46+00:00

tty_port_close_start() already validates the port counts and issues
a diagnostic if validation fails.

Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Remove tty_hung_up_p() tests from tty drivers' open()

2014-07-10T23:06:49+00:00

Since at least before 2.6.30, it has not been possible to observe
a hung up file pointer in a tty driver's open() method unless/until
the driver open() releases the tty_lock() (eg., before blocking).

This is because tty_open() adds the file pointer while holding
the tty_lock() _and_ doesn't release the lock until after calling
the tty driver's open() method. [ Before tty_lock(), this was
lock_kernel(). ]

Since __tty_hangup() first waits on the tty_lock() before
enumerating and hanging up the open file pointers, either
__tty_hangup() will wait for the tty_lock() or tty_open() will
not yet have added the file pointer. For example,

CPU 0                          |  CPU 1
                               |
tty_open                       |  __tty_hangup
  ..                           |    ..
  tty_lock                     |    ..
  tty_reopen                   |    tty_lock  / blocks
  ..                           |
  tty_add_file(tty, filp)      |
  ..                           |
  tty->ops->open(tty, filp)    |
    tty_port_open              |
      tty_port_block_til_ready |
        ..                     |
        while (1)              |
          ..                   |
          tty_unlock           |    / unblocks
          schedule             |    for each filp on tty->tty_files
                               |      f_ops = tty_hung_up_fops;
                               |    ..
                               |    tty_unlock
          tty_lock             |
  ..                           |
  tty_unlock                   |

Note that since tty_port_block_til_ready() and similar drop
the tty_lock while blocking, when woken, the file pointer
must then be tested for having been hung up.

Also, fix bit-rotted drivers that used extra_count to track the
port->count bump.

CC: Mikael Starvik 
CC: Samuel Ortiz 
CC: "David S. Miller" 
Signed-off-by: Peter Hurley 
Acked-by: Jesper Nilsson 
Signed-off-by: Greg Kroah-Hartman

tty: Fix help text of SYNCLINK_CS

2014-04-16T21:31:13+00:00

Enabling SYNCLINK_CS as a module builds synclink_cs, not synclinkmp.

Signed-off-by: Jean Delvare 
Signed-off-by: Greg Kroah-Hartman

tty: synclink: avoid sleep_on race

2014-01-08T01:05:21+00:00

The four variants of the synclink driver use the same code in their
open() callback to wait for a port in process of being closed,
using interruptible_sleep_on, which is racy and going away soon.

Making things worse, these functions hold the BTM while doing so,
which means that if we ever enter this code path, we cannot actually
continue since the other thread that is in process of closing the
port can no longer get the BTM.

This addresses both issues by using wait_event_interruptible_tty()
instead.

Signed-off-by: Arnd Bergmann 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Signed-off-by: Greg Kroah-Hartman

pcmcia: synclink_cs: replace sum of bitmasks with OR operation.

2013-07-27T00:59:07+00:00

Suggested by coccinelle and manually verified.

Signed-off-by: Alexandru Juncu 
Signed-off-by: Greg Kroah-Hartman

Finally eradicate CONFIG_HOTPLUG

2013-06-03T21:20:18+00:00

Ever since commit 45f035ab9b8f ("CONFIG_HOTPLUG should be always on"),
it has been basically impossible to build a kernel with CONFIG_HOTPLUG
turned off.  Remove all the remaining references to it.

Cc: Russell King 
Cc: Doug Thompson 
Cc: Bjorn Helgaas 
Cc: Steven Whitehouse 
Cc: Arnd Bergmann 
Cc: Pavel Machek 
Cc: "Rafael J. Wysocki" 
Cc: Andrew Morton 
Signed-off-by: Stephen Rothwell 
Acked-by: Mauro Carvalho Chehab 
Acked-by: Hans Verkuil 
Signed-off-by: Greg Kroah-Hartman