linux/ipc/sem.c, branch v2.6.26

ipc: sysvsem: implement sys_unshare(CLONE_SYSVSEM)

2008-04-29T15:06:14Z

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: consolidate all xxxctl_down() functions

2008-04-29T15:06:14Z

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()

2008-04-29T15:06:13Z

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.

2008-04-29T15:06:13Z

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()

2008-04-29T15:06:13Z

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

2008-04-29T15:06:13Z

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/semaphores: code factorisation

2008-04-29T15:06:13Z

Trivial patch which adds some small locking functions and makes use of them to factorize some part of the code and to make it cleaner. Signed-off-by: Pierre Peiffer Acked-by: Serge Hallyn Cc: Nadia Derbey Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

IPC: use ipc_buildid() directly from ipc_addid()

2008-04-29T15:06:12Z

By continuing to consolidate a little the IPC code, each id can be built directly in ipc_addid() instead of having it built from each callers of ipc_addid() And I also remove shm_addid() in order to have, as much as possible, the same code for shm/sem/msg. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Pierre Peiffer Cc: Nadia Derbey Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

IPC: consolidate sem_exit_ns(), msg_exit_ns() and shm_exit_ns()

2008-02-08T17:22:26Z

sem_exit_ns(), msg_exit_ns() and shm_exit_ns() are all called when an ipc_namespace is released to free all ipcs of each type. But in fact, they do the same thing: they loop around all ipcs to free them individually by calling a specific routine. This patch proposes to consolidate this by introducing a common function, free_ipcs(), that do the job. The specific routine to call on each individual ipcs is passed as parameter. For this, these ipc-specific 'free' routines are reworked to take a generic 'struct ipc_perm' as parameter. Signed-off-by: Pierre Peiffer Cc: Cedric Le Goater Cc: Pavel Emelyanov Cc: Nadia Derbey Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

IPC: make struct ipc_ids static in ipc_namespace

2008-02-08T17:22:26Z

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