lkml.org 
[lkml]   [2004]   [Sep]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subject[patch 1/3] uml-ubd-no-empty-queue
    From
    Date

    Avoid using, in the UBD driver, the elv_queue_empty function. It's for
    the block layer only; in fact, the Anticipatory Scheduler can return NULL
    with elv_next_request() even if the queue is not empty, because it waits
    for the process to send another request before seeking on the disk.

    In fact, if (with uml-ubd-any-elevator) we let UBD use any scheduler,
    elevator=as will make the UBD driver Oops, if we don't have this patch.

    Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>
    ---

    uml-linux-2.6.8.1-paolo/arch/um/drivers/ubd_kern.c | 6 ++----
    1 files changed, 2 insertions(+), 4 deletions(-)

    diff -puN arch/um/drivers/ubd_kern.c~uml-ubd-no-empty-queue arch/um/drivers/ubd_kern.c
    --- uml-linux-2.6.8.1/arch/um/drivers/ubd_kern.c~uml-ubd-no-empty-queue 2004-08-29 14:40:51.313410952 +0200
    +++ uml-linux-2.6.8.1-paolo/arch/um/drivers/ubd_kern.c 2004-08-29 14:40:51.315410648 +0200
    @@ -1038,8 +1038,7 @@ static void do_ubd_request(request_queue
    int err, n;

    if(thread_fd == -1){
    - while(!elv_queue_empty(q)){
    - req = elv_next_request(q);
    + while((req = elv_next_request(q)) != NULL){
    err = prepare_request(req, &io_req);
    if(!err){
    do_io(&io_req);
    @@ -1048,9 +1047,8 @@ static void do_ubd_request(request_queue
    }
    }
    else {
    - if(do_ubd || elv_queue_empty(q))
    + if(do_ubd || (req = elv_next_request(q)) == NULL)
    return;
    - req = elv_next_request(q);
    err = prepare_request(req, &io_req);
    if(!err){
    do_ubd = ubd_handler;
    _
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/
    \
     
     \ /
      Last update: 2005-03-22 14:05    [W:0.019 / U:30.396 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site