src/patches/suse-2.6.27.25/patches.arch/ppc-spufs-03-sputrace-Only-enable-logging-on-open.patch

   1 Subject: Only enable logging on open(), prevent multiple openers
   2 From: Jeremy Kerr <jk@ozlabs.org>
   3 References: 447133 - LTC50070
   4
   5 Currently, sputrace will start logging to the event buffer before the
   6 log buffer has been open()ed. This results in a heap of "lost samples"
   7 warnings if the sputrace file hasn't yet been opened.
   8
   9 Since the buffer is reset on open() anyway, there's no need to enable
  10 logging when no-one has opened the log.
  11
  12 Because open clears the log, make it return EBUSY for mutliple open
  13 calls.
  14
  15 Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
  16 Signed-off-by: Olaf Hering <olh@suse.de>
  17 ---
  18  arch/powerpc/platforms/cell/spufs/sputrace.c |   32 ++++++++++++++++++++++++---
  19  1 file changed, 29 insertions(+), 3 deletions(-)
  20
  21 --- a/arch/powerpc/platforms/cell/spufs/sputrace.c
  22 +++ b/arch/powerpc/platforms/cell/spufs/sputrace.c
  23 @@ -40,6 +40,7 @@ static DECLARE_WAIT_QUEUE_HEAD(sputrace_
  24  static ktime_t sputrace_start;
  25  static unsigned long sputrace_head, sputrace_tail;
  26  static struct sputrace *sputrace_log;
  27 +static int sputrace_logging;
  28
  29  static int sputrace_used(void)
  30  {
  31 @@ -109,24 +110,49 @@ static ssize_t sputrace_read(struct file
  32
  33  static int sputrace_open(struct inode *inode, struct file *file)
  34  {
  35 +       int rc;
  36 +
  37         spin_lock(&sputrace_lock);
  38 +       if (sputrace_logging) {
  39 +               rc = -EBUSY;
  40 +               goto out;
  41 +       }
  42 +
  43 +       sputrace_logging = 1;
  44         sputrace_head = sputrace_tail = 0;
  45         sputrace_start = ktime_get();
  46 +       rc = 0;
  47 +
  48 +out:
  49         spin_unlock(&sputrace_lock);
  50 +       return rc;
  51 +}
  52
  53 +static int sputrace_release(struct inode *inode, struct file *file)
  54 +{
  55 +       spin_lock(&sputrace_lock);
  56 +       sputrace_logging = 0;
  57 +       spin_unlock(&sputrace_lock);
  58         return 0;
  59  }
  60
  61  static const struct file_operations sputrace_fops = {
  62 -       .owner  = THIS_MODULE,
  63 -       .open   = sputrace_open,
  64 -       .read   = sputrace_read,
  65 +       .owner   = THIS_MODULE,
  66 +       .open    = sputrace_open,
  67 +       .read    = sputrace_read,
  68 +       .release = sputrace_release,
  69  };
  70
  71  static void sputrace_log_item(const char *name, struct spu_context *ctx,
  72                 struct spu *spu)
  73  {
  74         spin_lock(&sputrace_lock);
  75 +
  76 +       if (!sputrace_logging) {
  77 +               spin_unlock(&sputrace_lock);
  78 +               return;
  79 +       }
  80 +
  81         if (sputrace_avail() > 1) {
  82                 struct sputrace *t = sputrace_log + sputrace_head;
  83