int ret;
struct spu_context *ctx = file->private_data;
+ /* pre-check for file position: if we'd return EOF, there's no point
+ * causing a deschedule */
+ if (*pos >= sizeof(ctx->csa.lscsa->gprs))
+ return 0;
+
ret = spu_acquire_saved(ctx);
if (ret)
return ret;
static int spufs_switch_log_open(struct inode *inode, struct file *file)
{
struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
+ int rc;
+
+ rc = spu_acquire(ctx);
+ if (rc)
+ return rc;
- /*
- * We (ab-)use the mapping_lock here because it serves the similar
- * purpose for synchronizing open/close elsewhere. Maybe it should
- * be renamed eventually.
- */
- mutex_lock(&ctx->mapping_lock);
if (ctx->switch_log) {
- spin_lock(&ctx->switch_log->lock);
- ctx->switch_log->head = 0;
- ctx->switch_log->tail = 0;
- spin_unlock(&ctx->switch_log->lock);
- } else {
- /*
- * We allocate the switch log data structures on first open.
- * They will never be free because we assume a context will
- * be traced until it goes away.
- */
- ctx->switch_log = kzalloc(sizeof(struct switch_log) +
- SWITCH_LOG_BUFSIZE * sizeof(struct switch_log_entry),
- GFP_KERNEL);
- if (!ctx->switch_log)
- goto out;
- spin_lock_init(&ctx->switch_log->lock);
- init_waitqueue_head(&ctx->switch_log->wait);
+ rc = -EBUSY;
+ goto out;
}
- mutex_unlock(&ctx->mapping_lock);
+
+ ctx->switch_log = kmalloc(sizeof(struct switch_log) +
+ SWITCH_LOG_BUFSIZE * sizeof(struct switch_log_entry),
+ GFP_KERNEL);
+
+ if (!ctx->switch_log) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ ctx->switch_log->head = ctx->switch_log->tail = 0;
+ init_waitqueue_head(&ctx->switch_log->wait);
+ rc = 0;
+
+out:
+ spu_release(ctx);
+ return rc;
+}
+
+static int spufs_switch_log_release(struct inode *inode, struct file *file)
+{
+ struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
+ int rc;
+
+ rc = spu_acquire(ctx);
+ if (rc)
+ return rc;
+
+ kfree(ctx->switch_log);
+ ctx->switch_log = NULL;
+ spu_release(ctx);
return 0;
- out:
- mutex_unlock(&ctx->mapping_lock);
- return -ENOMEM;
}
static int switch_log_sprint(struct spu_context *ctx, char *tbuf, int n)
if (!buf || len < 0)
return -EINVAL;
+ error = spu_acquire(ctx);
+ if (error)
+ return error;
+
while (cnt < len) {
char tbuf[128];
int width;
- if (file->f_flags & O_NONBLOCK) {
- if (spufs_switch_log_used(ctx) <= 0)
- return cnt ? cnt : -EAGAIN;
- } else {
- /* Wait for data in buffer */
- error = wait_event_interruptible(ctx->switch_log->wait,
- spufs_switch_log_used(ctx) > 0);
- if (error)
+ if (spufs_switch_log_used(ctx) == 0) {
+ if (cnt > 0) {
+ /* If there's data ready to go, we can
+ * just return straight away */
+ break;
+
+ } else if (file->f_flags & O_NONBLOCK) {
+ error = -EAGAIN;
break;
- }
- spin_lock(&ctx->switch_log->lock);
- if (ctx->switch_log->head == ctx->switch_log->tail) {
- /* multiple readers race? */
- spin_unlock(&ctx->switch_log->lock);
- continue;
+ } else {
+ /* spufs_wait will drop the mutex and
+ * re-acquire, but since we're in read(), the
+ * file cannot be _released (and so
+ * ctx->switch_log is stable).
+ */
+ error = spufs_wait(ctx->switch_log->wait,
+ spufs_switch_log_used(ctx) > 0);
+
+ /* On error, spufs_wait returns without the
+ * state mutex held */
+ if (error)
+ return error;
+
+ /* We may have had entries read from underneath
+ * us while we dropped the mutex in spufs_wait,
+ * so re-check */
+ if (spufs_switch_log_used(ctx) == 0)
+ continue;
+ }
}
width = switch_log_sprint(ctx, tbuf, sizeof(tbuf));
- if (width < len) {
+ if (width < len)
ctx->switch_log->tail =
(ctx->switch_log->tail + 1) %
SWITCH_LOG_BUFSIZE;
- }
-
- spin_unlock(&ctx->switch_log->lock);
-
- /*
- * If the record is greater than space available return
- * partial buffer (so far)
- */
- if (width >= len)
+ else
+ /* If the record is greater than space available return
+ * partial buffer (so far) */
break;
error = copy_to_user(buf + cnt, tbuf, width);
cnt += width;
}
+ spu_release(ctx);
+
return cnt == 0 ? error : cnt;
}
struct inode *inode = file->f_path.dentry->d_inode;
struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
unsigned int mask = 0;
+ int rc;
poll_wait(file, &ctx->switch_log->wait, wait);
+ rc = spu_acquire(ctx);
+ if (rc)
+ return rc;
+
if (spufs_switch_log_used(ctx) > 0)
mask |= POLLIN;
+ spu_release(ctx);
+
return mask;
}
static const struct file_operations spufs_switch_log_fops = {
- .owner = THIS_MODULE,
- .open = spufs_switch_log_open,
- .read = spufs_switch_log_read,
- .poll = spufs_switch_log_poll,
+ .owner = THIS_MODULE,
+ .open = spufs_switch_log_open,
+ .read = spufs_switch_log_read,
+ .poll = spufs_switch_log_poll,
+ .release = spufs_switch_log_release,
};
+/**
+ * Log a context switch event to a switch log reader.
+ *
+ * Must be called with ctx->state_mutex held.
+ */
void spu_switch_log_notify(struct spu *spu, struct spu_context *ctx,
u32 type, u32 val)
{
if (!ctx->switch_log)
return;
- spin_lock(&ctx->switch_log->lock);
if (spufs_switch_log_avail(ctx) > 1) {
struct switch_log_entry *p;
ctx->switch_log->head =
(ctx->switch_log->head + 1) % SWITCH_LOG_BUFSIZE;
}
- spin_unlock(&ctx->switch_log->lock);
wake_up(&ctx->switch_log->wait);
}
projects / linux-2.6-omap-h63xx.git / blobdiff