Re: [PATCHv2 2/2] media: venus: sync with threaded IRQ during inst destruction

[Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>]

On (24/10/24 19:08), Sergey Senozhatsky wrote:
> So, we need to
> - export a couple of symbols
> - include vdec header in core
[..]
> +++ b/drivers/media/platform/qcom/venus/core.c
> @@ -500,6 +500,31 @@ static __maybe_unused int venus_runtime_suspend(struct device *dev)
>  	return ret;
>  }
>  
> +void venus_close_common(struct venus_inst *inst)
> +{
> +	/*
> +	 * First, remove the inst from the ->instances list, so that
> +	 * to_instance() will return NULL.
> +	 */
> +	hfi_session_destroy(inst);
> +	/*
> +	 * Second, make sure we don't have IRQ/IRQ-thread currently running
> +	 * or pending execution, which would race with the inst destruction.
> +	 */
> +	synchronize_irq(inst->core->irq);
> +
> +	v4l2_m2m_ctx_release(inst->m2m_ctx);
> +	v4l2_m2m_release(inst->m2m_dev);
> +	ida_destroy(&inst->dpb_ids);
> +	v4l2_fh_del(&inst->fh);
> +	v4l2_fh_exit(&inst->fh);
> +	vdec_ctrl_deinit(inst);
> +
> +	mutex_destroy(&inst->lock);
> +	mutex_destroy(&inst->ctx_q_lock);
> +}
> +EXPORT_SYMBOL_GPL(venus_close_common);
[..]
> +++ b/drivers/media/platform/qcom/venus/core.h
> @@ -17,6 +17,7 @@
>  #include "hfi.h"
>  #include "hfi_platform.h"
>  #include "hfi_helper.h"
> +#include "vdec.h"
>  
>  #define VDBGL	"VenusLow : "
>  #define VDBGM	"VenusMed : "
> @@ -569,4 +570,6 @@ is_fw_rev_or_older(struct venus_core *core, u32 vmajor, u32 vminor, u32 vrev)
>  		(core)->venus_ver.minor == vminor &&
>  		(core)->venus_ver.rev <= vrev);
>  }
> +
> +void venus_close_common(struct venus_inst *inst);
>  #endif
[..]
> +++ b/drivers/media/platform/qcom/venus/vdec_ctrls.c
> @@ -192,3 +192,4 @@ void vdec_ctrl_deinit(struct venus_inst *inst)
>  {
>  	v4l2_ctrl_handler_free(&inst->ctrl_handler);
>  }
> +EXPORT_SYMBOL_GPL(vdec_ctrl_deinit);

Would have been entirely too simple had I compile-tested
my patches, wouldn't it?

	depmod: ERROR: Cycle detected: venus_core -> venus_dec -> venus_core


vdec_ctrl_deinit() is a v4l2_ctrl_handler_free() wrapper, a one-liner,
so I turned into a static inline.

Compiles with the addition of:

---

diff --git a/drivers/media/platform/qcom/venus/vdec.h b/drivers/media/platform/qcom/venus/vdec.h
index 6b262d0bf561..2687255b1616 100644
--- a/drivers/media/platform/qcom/venus/vdec.h
+++ b/drivers/media/platform/qcom/venus/vdec.h
@@ -6,9 +6,14 @@
 #ifndef __VENUS_VDEC_H__
 #define __VENUS_VDEC_H__
 
+#include <media/v4l2-ctrls.h>
+
 struct venus_inst;
 
 int vdec_ctrl_init(struct venus_inst *inst);
-void vdec_ctrl_deinit(struct venus_inst *inst);
+static inline void vdec_ctrl_deinit(struct venus_inst *inst)
+{
+       v4l2_ctrl_handler_free(&inst->ctrl_handler);
+}
 
 #endif
diff --git a/drivers/media/platform/qcom/venus/vdec_ctrls.c b/drivers/media/platform/qcom/venus/vdec_ctrls.c
index 2b6b2eee619c..fa034a7fdbed 100644
--- a/drivers/media/platform/qcom/venus/vdec_ctrls.c
+++ b/drivers/media/platform/qcom/venus/vdec_ctrls.c
@@ -4,7 +4,6 @@
  * Copyright (C) 2017 Linaro Ltd.
  */
 #include <linux/types.h>
-#include <media/v4l2-ctrls.h>
 
 #include "core.h"
 #include "helpers.h"
@@ -187,9 +186,3 @@ int vdec_ctrl_init(struct venus_inst *inst)
 
        return 0;
 }
-
-void vdec_ctrl_deinit(struct venus_inst *inst)
-{
-       v4l2_ctrl_handler_free(&inst->ctrl_handler);
-}