09 Feb, 2008

3 commits

  • 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

    Pierre Peiffer
     
  • 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

    Pierre Peiffer
     
  • 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

    Pavel Emelyanov