linux-toradex.git/ipc, branch v2.6.26-rc2

tiny mq_open optimization

2008-05-03T20:50:33+00:00

A very small cleanup for mq_open.

We do not have to call set_close_on_exit if we create the file
descriptor right away with the flag set.  We have a function for this
now.  The resulting code is smaller and a tiny bit faster.

Signed-off-by: Ulrich Drepper 
Signed-off-by: Linus Torvalds

sysvipc: use non-racy method for proc entries creation

2008-04-29T15:06:20+00:00

Use proc_create_data() to make sure that ->proc_fops and ->data be setup
before gluing PDE to main tree.

Signed-off-by: Denis V. Lunev 
Cc: Alexey Dobriyan 
Cc: "Eric W. Biederman" 
Cc: Nadia Derbey 
Cc: Pierre Peiffer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: sysvsem: implement sys_unshare(CLONE_SYSVSEM)

2008-04-29T15:06:14+00:00

sys_unshare(CLONE_NEWIPC) doesn't handle the undo lists properly, this can
cause a kernel memory corruption.  CLONE_NEWIPC must detach from the existing
undo lists.

Fix, part 1: add support for sys_unshare(CLONE_SYSVSEM)

The original reason to not support it was the potential (inevitable?)
confusion due to the fact that sys_unshare(CLONE_SYSVSEM) has the
inverse meaning of clone(CLONE_SYSVSEM).

Our two most reasonable options then appear to be (1) fully support
CLONE_SYSVSEM, or (2) continue to refuse explicit CLONE_SYSVSEM,
but always do it anyway on unshare(CLONE_SYSVSEM).  This patch does
(1).

Changelog:
	Apr 16: SEH: switch to Manfred's alternative patch which
		removes the unshare_semundo() function which
		always refused CLONE_SYSVSEM.

Signed-off-by: Manfred Spraul 
Signed-off-by: Serge E. Hallyn 
Acked-by: "Eric W. Biederman" 
Cc: Pavel Emelyanov 
Cc: Michael Kerrisk 
Cc: Pierre Peiffer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: add definitions of USHORT_MAX and others

2008-04-29T15:06:14+00:00

Add definitions of USHORT_MAX and others into kernel.  ipc uses it and slub
implementation might also use it.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Zhang Yanmin 
Reviewed-by: Christoph Lameter 
Cc: Nadia Derbey 
Cc: "Pierre Peiffer" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

IPC: consolidate all xxxctl_down() functions

2008-04-29T15:06:14+00:00

semctl_down(), msgctl_down() and shmctl_down() are used to handle the same set
of commands for each kind of IPC.  They all start to do the same job (they
retrieve the ipc and do some permission checks) before handling the commands
on their own.

This patch proposes to consolidate this by moving these same pieces of code
into one common function called ipcctl_pre_down().

It simplifies a little these xxxctl_down() functions and increases a little
the maintainability.

Signed-off-by: Pierre Peiffer 
Acked-by: Serge Hallyn 
Cc: Nadia Derbey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

IPC: introduce ipc_update_perm()

2008-04-29T15:06:13+00:00

The IPC_SET command performs the same permission setting for all IPCs.  This
patch introduces a common ipc_update_perm() function to update these
permissions and makes use of it for all IPCs.

Signed-off-by: Pierre Peiffer 
Acked-by: Serge Hallyn 
Cc: Nadia Derbey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

IPC: get rid of the use *_setbuf structure.

2008-04-29T15:06:13+00:00

All IPCs make use of an intermetiate *_setbuf structure to handle the IPC_SET
command.  This is not really needed and, moreover, it complicates a little bit
the code.

This patch gets rid of the use of it and uses directly the semid64_ds/
msgid64_ds/shmid64_ds structure.

In addition of removing one struture declaration, it also simplifies and
improves a little bit the common 64-bits path.

Signed-off-by: Pierre Peiffer 
Acked-by: Serge Hallyn 
Cc: Nadia Derbey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

IPC/semaphores: remove one unused parameter from semctl_down()

2008-04-29T15:06:13+00:00

semctl_down() takes one unused parameter: semnum.  This patch proposes to get
rid of it.

Signed-off-by: Pierre Peiffer 
Acked-by: Serge Hallyn 
Cc: Nadia Derbey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

IPC/semaphores: move the rwmutex handling inside semctl_down

2008-04-29T15:06:13+00:00

semctl_down is called with the rwmutex (the one which protects the list of
ipcs) taken in write mode.

This patch moves this rwmutex taken in write-mode inside semctl_down.

This has the advantages of reducing a little bit the window during which this
rwmutex is taken, clarifying sys_semctl, and finally of having a coherent
behaviour with [shm|msg]ctl_down

Signed-off-by: Pierre Peiffer 
Acked-by: Serge Hallyn 
Cc: Nadia Derbey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

IPC/message queues: introduce msgctl_down

2008-04-29T15:06:13+00:00

Currently, sys_msgctl is not easy to read.

This patch tries to improve that by introducing the msgctl_down function to
handle all commands requiring the rwmutex to be taken in write mode (ie
IPC_SET and IPC_RMID for now).  It is the equivalent function of semctl_down
for message queues.

This greatly changes the readability of sys_msgctl and also harmonizes the way
these commands are handled among all IPCs.

Signed-off-by: Pierre Peiffer 
Acked-by: Serge Hallyn 
Cc: Nadia Derbey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds