linux.git/drivers/char/tty_io.c, branch master

TTY: create drivers/tty and move the tty core files there

2010-11-05T15:10:33+00:00

The tty code should be in its own subdirectory and not in the char
driver with all of the cruft that is currently there.

Based on work done by Arnd Bergmann 

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

tty: Make tiocgicount a handler

2010-10-22T17:20:04+00:00

Dan Rosenberg noted that various drivers return the struct with uncleared
fields. Instead of spending forever trying to stomp all the drivers that
get it wrong (and every new driver) do the job in one place.

This first patch adds the needed operations and hooks them up, including
the needed USB midlayer and serial core plumbing.

Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty_io: check return code of tty_register_device

2010-10-22T17:20:03+00:00

Function tty_register_device may return ERR_PTR(...). Check for it.

Signed-off-by: Vasiliy Kulikov 
Signed-off-by: Greg Kroah-Hartman

tty: Remove __GFP_NOFAIL from tty_add_file()

2010-10-22T17:19:58+00:00

This patch removes __GFP_NOFAIL use from tty_add_file() and adds proper error
handling to the call-sites of the function.

Cc: Andrew Morton 
Cc: Alan Cox 
Cc: Arnd Bergmann 
Signed-off-by: Pekka Enberg 
Acked-by: David Rientjes 
Signed-off-by: Greg Kroah-Hartman

tty: add tty_struct->dev pointer to corresponding device instance

2010-10-22T17:19:56+00:00

Some device drivers (mostly tty line disciplines) would like to have way
know a struct device instance corresponding to passed tty_struct. Add
a struct device pointer to struct tty_struct and populate it during
initialize_tty_struct().

Signed-off-by: Dmitry Eremin-Solenikov 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty: fix tty_line must not be equal to number of allocated tty pointers in tty driver

2010-09-04T00:29:04+00:00

I found a bug "by chance" in drivers/char/tty_io.c

I mean "by chance" because I was just reading the code of the
tty_find_polling_driver() to make a new tty_find_by_name() function.

In tty_find_polling_driver() the driver actually test "tty_line <=
p->num" while num refers to the number of struct tty_struct pointers
allocated for the p->ttys (p is a tty_driver), and tty_line is scanned
in a tty name, which can be for example ttyS2. Then tty_line equals 2.
And if p->num is 2, we have only p->ttys[0] and p->ttys[1], but no
p->ttys[2].

This is actually unharmful, for tty_find_polling_driver() is used only
in drivers/serial/kgdboc.c, and there's a test over there to find a
console with a matching index, which will never happen.

This is still a bug anyway.

Signed-off-by: Nathael Pajani 
Signed-off-by: Greg Kroah-Hartman

tty: fix fu_list abuse

2010-08-18T12:35:47+00:00

tty: fix fu_list abuse

tty code abuses fu_list, which causes a bug in remount,ro handling.

If a tty device node is opened on a filesystem, then the last link to the inode
removed, the filesystem will be allowed to be remounted readonly. This is
because fs_may_remount_ro does not find the 0 link tty inode on the file sb
list (because the tty code incorrectly removed it to use for its own purpose).
This can result in a filesystem with errors after it is marked "clean".

Taking idea from Christoph's initial patch, allocate a tty private struct
at file->private_data and put our required list fields in there, linking
file and tty. This makes tty nodes behave the same way as other device nodes
and avoid meddling with the vfs, and avoids this bug.

The error handling is not trivial in the tty code, so for this bugfix, I take
the simple approach of using __GFP_NOFAIL and don't worry about memory errors.
This is not a problem because our allocator doesn't fail small allocs as a rule
anyway. So proper error handling is left as an exercise for tty hackers.

[ Arguably filesystem's device inode would ideally be divorced from the
driver's pseudo inode when it is opened, but in practice it's not clear whether
that will ever be worth implementing. ]

Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig 
Cc: Alan Cox 
Cc: Greg Kroah-Hartman 
Signed-off-by: Nick Piggin 
Signed-off-by: Al Viro

fs: cleanup files_lock locking

2010-08-18T12:35:47+00:00

fs: cleanup files_lock locking

Lock tty_files with a new spinlock, tty_files_lock; provide helpers to
manipulate the per-sb files list; unexport the files_lock spinlock.

Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig 
Cc: Alan Cox 
Acked-by: Andi Kleen 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Nick Piggin 
Signed-off-by: Al Viro

tty_io: remove casts from void*

2010-08-10T20:47:44+00:00

Remove unnesessary casts from void*.

Signed-off-by: Kulikov Vasiliy 
Signed-off-by: Greg Kroah-Hartman

tty: avoid recursive BTM in pty_close

2010-08-10T20:47:44+00:00

When the console has been redirected, a hangup of the tty
will cause tty_release to be called under the big tty_mutex,
which leads to a deadlock because hangup is also called
under the BTM.

This moves the BTM deeper into the tty_hangup function so
we can close the redirected tty without holding the BTM.
In case of pty, we now need to drop the BTM before
calling tty_vhangup.

Signed-off-by: Arnd Bergmann 
Acked-by: Alan Cox 
Cc: Tony Luck 
Cc: Thomas Gleixner 
Cc: Andrew Morton 
Cc: John Kacur 
Cc: Al Viro 
Cc: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman