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    SubjectRe: inappropriate use of in_atomic()
    Hi Andrew,

    On Thu, 10 Mar 2005 20:40:06 -0800 Andrew Morton <akpm@osdl.org> wrote:
    >
    > in_atomic() is not a reliable indication of whether it is currently safe
    > to call schedule().
    >
    > arch/ppc64/kernel/viopath.c

    in_atomic() in viopath.c was just used to determine if we had initialised
    enough to be able to wait in a semaphore (i.e. schedule). Thus it can be
    replaced now with checking system_state for SYSTEM_RUNNING.

    Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

    Test booted on iSeries (which is the only place it is used).
    --
    Cheers,
    Stephen Rothwell sfr@canb.auug.org.au
    http://www.canb.auug.org.au/~sfr/

    diff -ruNp linus/arch/ppc64/kernel/viopath.c linus-in_atomic/arch/ppc64/kernel/viopath.c
    --- linus/arch/ppc64/kernel/viopath.c 2005-01-22 06:09:01.000000000 +1100
    +++ linus-in_atomic/arch/ppc64/kernel/viopath.c 2005-03-11 17:19:45.000000000 +1100
    @@ -79,7 +79,7 @@ static void handleMonitorEvent(struct Hv
    /*
    * We use this structure to handle asynchronous responses. The caller
    * blocks on the semaphore and the handler posts the semaphore. However,
    - * if in_atomic() is true in the caller, then wait_atomic is used ...
    + * if system_state is not SYSTEM_RUNNING, then wait_atomic is used ...
    */
    struct doneAllocParms_t {
    struct semaphore *sem;
    @@ -465,7 +465,7 @@ static int allocateEvents(HvLpIndex remo
    DECLARE_MUTEX_LOCKED(Semaphore);
    atomic_t wait_atomic;

    - if (in_atomic()) {
    + if (system_state != SYSTEM_RUNNING) {
    parms.used_wait_atomic = 1;
    atomic_set(&wait_atomic, 1);
    parms.wait_atomic = &wait_atomic;
    @@ -475,7 +475,7 @@ static int allocateEvents(HvLpIndex remo
    }
    mf_allocate_lp_events(remoteLp, HvLpEvent_Type_VirtualIo, 250, /* It would be nice to put a real number here! */
    numEvents, &viopath_donealloc, &parms);
    - if (in_atomic()) {
    + if (system_state != SYSTEM_RUNNING) {
    while (atomic_read(&wait_atomic))
    mb();
    } else[unhandled content-type:application/pgp-signature]
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