linux-toradex.git/ipc/util.h, branch v2.6.27.10

ipc: get rid of ipc_lock_down()

2008-07-25T17:53:42+00:00

Remove the ipc_lock_down() routines: they used to call idr_find() locklessly
(given that the ipc ids lock was already held), so they are not needed
anymore.

Signed-off-by: Nadia Derbey 
Acked-by: "Paul E. McKenney" 
Cc: Manfred Spraul 
Cc: Jim Houston 
Cc: Pierre Peiffer 
Acked-by: Rik van Riel 
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: recompute msgmni on memory add / remove

2008-04-29T15:06:12+00:00

Introduce the registration of a callback routine that recomputes msg_ctlmni
upon memory add / remove.

A single notifier block is registered in the hotplug memory chain for all the
ipc namespaces.

Since the ipc namespaces are not linked together, they have their own
notification chain: one notifier_block is defined per ipc namespace.

Each time an ipc namespace is created (removed) it registers (unregisters) its
notifier block in (from) the ipcns chain.  The callback routine registered in
the memory chain invokes the ipcns notifier chain with the IPCNS_LOWMEM event.
 Each callback routine registered in the ipcns namespace, in turn, recomputes
msgmni for the owning namespace.

Signed-off-by: Nadia Derbey 
Cc: Yasunori Goto 
Cc: Matt Helsley 
Cc: Mingming Cao 
Cc: Pierre Peiffer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

IPC: make struct ipc_ids static in ipc_namespace

2008-02-08T17:22:26+00:00

Each ipc_namespace contains a table of 3 pointers to struct ipc_ids (3 for
msg, sem and shm, structure used to store all ipcs) These 'struct ipc_ids'
are dynamically allocated for each icp_namespace as the ipc_namespace
itself (for the init namespace, they are initialized with pointers to
static variables instead)

It is so for historical reason: in fact, before the use of idr to store the
ipcs, the ipcs were stored in tables of variable length, depending of the
maximum number of ipc allowed.  Now, these 'struct ipc_ids' have a fixed
size.  As they are allocated in any cases for each new ipc_namespace, there
is no gain of memory in having them allocated separately of the struct
ipc_namespace.

This patch proposes to make this table static in the struct ipc_namespace.
Thus, we can allocate all in once and get rid of all the code needed to
allocate and free these ipc_ids separately.

Signed-off-by: Pierre Peiffer 
Acked-by: Cedric Le Goater 
Cc: Pavel Emelyanov 
Cc: Nadia Derbey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: uninline some code from util.h

2008-02-08T17:22:25+00:00

ipc_lock_check_down(), ipc_lock_check() and ipcget() seem too large to be
inline.  Besides, they give no optimization being inline as they perform
calls inside in any case.

Moving them into ipc/util.c saves 500 bytes of vmlinux and shortens IPC
internal API.

$ ./scripts/bloat-o-meter vmlinux-orig vmlinux
add/remove: 3/2 grow/shrink: 0/10 up/down: 490/-989 (-499)
function                                     old     new   delta
ipcget                                         -     392    +392
ipc_lock_check_down                            -      49     +49
ipc_lock_check                                 -      49     +49
sys_semget                                   119     105     -14
sys_shmget                                   108      86     -22
sys_msgget                                   100      78     -22
do_msgsnd                                    665     631     -34
do_msgrcv                                    680     644     -36
do_shmat                                     771     733     -38
sys_msgctl                                  1302    1229     -73
ipcget_new                                    80       -     -80
sys_semtimedop                              1534    1452     -82
sys_semctl                                  2034    1922    -112
sys_shmctl                                  1919    1765    -154
ipcget_public                                322       -    -322

The ipcget() growth is the result of gcc inlining of currently static
ipcget_new/_public.

Signed-off-by: Pavel Emelyanov 
Cc: Nadia Derbey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

namespaces: move the IPC namespace under IPC_NS option

2008-02-08T17:22:23+00:00

Currently the IPC namespace management code is spread over the ipc/*.c files.
I moved this code into ipc/namespace.c file which is compiled out when needed.

The linux/ipc_namespace.h file is used to store the prototypes of the
functions in namespace.c and the stubs for NAMESPACES=n case.  This is done
so, because the stub for copy_ipc_namespace requires the knowledge of the
CLONE_NEWIPC flag, which is in sched.h.  But the linux/ipc.h file itself in
included into many many .c files via the sys.h->sem.h sequence so adding the
sched.h into it will make all these .c depend on sched.h which is not that
good.  On the other hand the knowledge about the namespaces stuff is required
in 4 .c files only.

Besides, this patch compiles out some auxiliary functions from ipc/sem.c,
msg.c and shm.c files.  It turned out that moving these functions into
namespaces.c is not that easy because they use many other calls and macros
from the original file.  Moving them would make this patch complicated.  On
the other hand all these functions can be consolidated, so I will send a
separate patch doing this a bit later.

Signed-off-by: Pavel Emelyanov 
Acked-by: Serge Hallyn 
Cc: Cedric Le Goater 
Cc: "Eric W. Biederman" 
Cc: Herbert Poetzl 
Cc: Kirill Korotaev 
Cc: Sukadev Bhattiprolu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: remove unneeded parameters

2007-10-19T18:53:48+00:00

Remvoe the unneeded parameters from ipc_checkid() and ipc_buildid()
interfaces.

Signed-off-by: Nadia Derbey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fix idr_find() locking

2007-10-19T18:53:48+00:00

This is a patch that fixes the way idr_find() used to be called in ipc_lock():
in all the paths that don't imply an update of the ipcs idr, it was called
without the idr tree being locked.

The changes are:
  . in ipc_ids, the mutex has been changed into a reader/writer semaphore.
  . ipc_lock() now takes the mutex as a reader during the idr_find().
  . a new routine ipc_lock_down() has been defined: it doesn't take the
    mutex, assuming that it is being held by the caller. This is the routine
    that is now called in all the update paths.

Signed-off-by: Nadia Derbey 
Acked-by: Jarek Poplawski 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds