[Intel-gfx] [PATCH 09/19] drm/i915/perf: Replace gt->perf.lock with stream->lock for file ops

Umesh Nerlige Ramappa
2022-08-23T20:42:50Z

With multi-gt, user can access multiple OA buffers concurrently. Use
stream->lock instead of gt->perf.lock to serialize file operations.

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
---
drivers/gpu/drm/i915/i915_perf.c | 31 ++++++++++++--------------
drivers/gpu/drm/i915/i915_perf_types.h | 5 +++++
2 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 5dccb3ffffc5..87b92d2946f4 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -3244,6 +3244,7 @@ static int i915_oa_stream_init(struct i915_perf_stream *stream,
stream->poll_check_timer.function = oa_poll_check_timer_cb;
init_waitqueue_head(&stream->poll_wq);
spin_lock_init(&stream->oa_buffer.ptr_lock);
+ mutex_init(&stream->lock);

return 0;

@@ -3307,7 +3308,6 @@ static ssize_t i915_perf_read(struct file *file,
loff_t *ppos)
{
struct i915_perf_stream *stream = file->private_data;
- struct intel_gt *gt = stream->engine->gt;
size_t offset = 0;
int ret;

@@ -3331,14 +3331,14 @@ static ssize_t i915_perf_read(struct file *file,
if (ret)
return ret;

- mutex_lock(&gt->perf.lock);
+ mutex_lock(&stream->lock);
ret = stream->ops->read(stream, buf, count, &offset);
- mutex_unlock(&gt->perf.lock);
+ mutex_unlock(&stream->lock);
} while (!offset && !ret);
} else {
- mutex_lock(&gt->perf.lock);
+ mutex_lock(&stream->lock);
ret = stream->ops->read(stream, buf, count, &offset);
- mutex_unlock(&gt->perf.lock);
+ mutex_unlock(&stream->lock);
}

/* We allow the poll checking to sometimes report false positive EPOLLIN
@@ -3385,9 +3385,6 @@ static enum hrtimer_restart oa_poll_check_timer_cb(struct hrtimer *hrtimer)
* &i915_perf_stream_ops->poll_wait to call poll_wait() with a wait queue that
* will be woken for new stream data.
*
- * Note: The &gt->perf.lock mutex has been taken to serialize
- * with any non-file-operation driver hooks.
- *
* Returns: any poll events that are ready without sleeping
*/
static __poll_t i915_perf_poll_locked(struct i915_perf_stream *stream,
@@ -3426,12 +3423,11 @@ static __poll_t i915_perf_poll_locked(struct i915_perf_stream *stream,
static __poll_t i915_perf_poll(struct file *file, poll_table *wait)
{
struct i915_perf_stream *stream = file->private_data;
- struct intel_gt *gt = stream->engine->gt;
__poll_t ret;

- mutex_lock(&gt->perf.lock);
+ mutex_lock(&stream->lock);
ret = i915_perf_poll_locked(stream, file, wait);
- mutex_unlock(&gt->perf.lock);
+ mutex_unlock(&stream->lock);

return ret;
}
@@ -3530,9 +3526,6 @@ static long i915_perf_config_locked(struct i915_perf_stream *stream,
* @cmd: the ioctl request
* @arg: the ioctl data
*
- * Note: The &gt->perf.lock mutex has been taken to serialize
- * with any non-file-operation driver hooks.
- *
* Returns: zero on success or a negative error code. Returns -EINVAL for
* an unknown ioctl request.
*/
@@ -3570,12 +3563,11 @@ static long i915_perf_ioctl(struct file *file,
unsigned long arg)
{
struct i915_perf_stream *stream = file->private_data;
- struct intel_gt *gt = stream->engine->gt;
long ret;

- mutex_lock(&gt->perf.lock);
+ mutex_lock(&stream->lock);
ret = i915_perf_ioctl_locked(stream, cmd, arg);
- mutex_unlock(&gt->perf.lock);
+ mutex_unlock(&stream->lock);

return ret;
}
@@ -3621,6 +3613,11 @@ static int i915_perf_release(struct inode *inode, struct file *file)
struct i915_perf *perf = stream->perf;
struct intel_gt *gt = stream->engine->gt;

+ /*
+ * Within this call, we know that the fd is being closed and we have no
+ * other user of stream->lock. Use the perf lock to destroy the stream
+ * here.
+ */
mutex_lock(&gt->perf.lock);
i915_perf_destroy_locked(stream);
mutex_unlock(&gt->perf.lock);
diff --git a/drivers/gpu/drm/i915/i915_perf_types.h b/drivers/gpu/drm/i915/i915_perf_types.h
index e888bfab478f..dc9bfd8086cf 100644
--- a/drivers/gpu/drm/i915/i915_perf_types.h
+++ b/drivers/gpu/drm/i915/i915_perf_types.h
@@ -146,6 +146,11 @@ struct i915_perf_stream {
*/
struct intel_engine_cs *engine;

+ /*
+ * Lock associated with operations on stream
+ */
+ struct mutex lock;
+
/**
* @sample_flags: Flags representing the `DRM_I915_PERF_PROP_SAMPLE_*`
* properties given when opening a stream, representing the contents
--
2.25.1