From baf399273f2ea38e2fcbd4d0b6cc7ba7f7db43eb Mon Sep 17 00:00:00 2001
From: Jeremy Kerr <jk@ozlabs.org>
Date: Wed, 15 Oct 2008 13:16:18 +1100
Subject: powerpc/spufs: sputrace: Only enable logging on open(), prevent
multiple openers
Currently, sputrace will start logging to the event buffer before the
log buffer has been open()ed. This results in a heap of "lost samples"
warnings if the sputrace file hasn't yet been opened.
Since the buffer is reset on open() anyway, there's no need to enable
logging when no-one has opened the log.
Because open clears the log, make it return EBUSY for mutliple open
calls.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
---
arch/powerpc/platforms/cell/spufs/sputrace.c | 32 +++++++++++++++++++++++++---
1 file changed, 29 insertions(+), 3 deletions(-)
(limited to 'arch/powerpc')
diff --git a/arch/powerpc/platforms/cell/spufs/sputrace.c b/arch/powerpc/platforms/cell/spufs/sputrace.c
index 92d20e9..50cae0c 100644
--- a/arch/powerpc/platforms/cell/spufs/sputrace.c
+++ b/arch/powerpc/platforms/cell/spufs/sputrace.c
@@ -40,6 +40,7 @@ static DECLARE_WAIT_QUEUE_HEAD(sputrace_wait);
static ktime_t sputrace_start;
static unsigned long sputrace_head, sputrace_tail;
static struct sputrace *sputrace_log;
+static int sputrace_logging;
static int sputrace_used(void)
{
@@ -109,24 +110,49 @@ static ssize_t sputrace_read(struct file *file, char __user *buf,
static int sputrace_open(struct inode *inode, struct file *file)
{
+ int rc;
+
spin_lock(&sputrace_lock);
+ if (sputrace_logging) {
+ rc = -EBUSY;
+ goto out;
+ }
+
+ sputrace_logging = 1;
sputrace_head = sputrace_tail = 0;
sputrace_start = ktime_get();
+ rc = 0;
+
+out:
spin_unlock(&sputrace_lock);
+ return rc;
+}
+static int sputrace_release(struct inode *inode, struct file *file)
+{
+ spin_lock(&sputrace_lock);
+ sputrace_logging = 0;
+ spin_unlock(&sputrace_lock);
return 0;
}
static const struct file_operations sputrace_fops = {
- .owner = THIS_MODULE,
- .open = sputrace_open,
- .read = sputrace_read,
+ .owner = THIS_MODULE,
+ .open = sputrace_open,
+ .read = sputrace_read,
+ .release = sputrace_release,
};
static void sputrace_log_item(const char *name, struct spu_context *ctx,
struct spu *spu)
{
spin_lock(&sputrace_lock);
+
+ if (!sputrace_logging) {
+ spin_unlock(&sputrace_lock);
+ return;
+ }
+
if (sputrace_avail() > 1) {
struct sputrace *t = sputrace_log + sputrace_head;
--
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