bus: mhi: core: Drop the references to mhi_dev in mhi_destroy_device() (3eb583a6) · Commits · 戴 / test

For some scenarios like controller suspend and resume, mhi_destroy_device() will get called without mhi_unregister_controller(). In that case, the references to the mhi_dev created for the channels will not be dropped but the channels will be destroyed as per the spec. This will cause issue during resume as the channels will not be created due to the fact that mhi_dev is not NULL. Hence, this change decrements the refcount for mhi_dev in mhi_destroy_device() for concerned channels and also sets mhi_dev to NULL in release_device(). Reported-by:

Carl Huang <cjhuang@codeaurora.org> Reviewed-by:

Jeffrey Hugo <jhugo@codeaurora.org> Signed-off-by:

Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Link: https://lore.kernel.org/r/20200324061050.14845-5-manivannan.sadhasivam@linaro.org Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/bus/mhi/core/init.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -1028,6 +1028,18 @@ static void mhi_release_device(struct device *dev)
		{
		struct mhi_device *mhi_dev = to_mhi_device(dev);

		/*
		* We need to set the mhi_chan->mhi_dev to NULL here since the MHI
		* devices for the channels will only get created if the mhi_dev
		* associated with it is NULL. This scenario will happen during the
		* controller suspend and resume.
		*/
		if (mhi_dev->ul_chan)
		mhi_dev->ul_chan->mhi_dev = NULL;

		if (mhi_dev->dl_chan)
		mhi_dev->dl_chan->mhi_dev = NULL;

		kfree(mhi_dev);
		}

drivers/bus/mhi/core/main.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -244,6 +244,19 @@ int mhi_destroy_device(struct device dev, void data)
		if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER)
		return 0;

		/*
		* For the suspend and resume case, this function will get called
		* without mhi_unregister_controller(). Hence, we need to drop the
		* references to mhi_dev created for ul and dl channels. We can
		* be sure that there will be no instances of mhi_dev left after
		* this.
		*/
		if (mhi_dev->ul_chan)
		put_device(&mhi_dev->ul_chan->mhi_dev->dev);

		if (mhi_dev->dl_chan)
		put_device(&mhi_dev->dl_chan->mhi_dev->dev);

		dev_dbg(&mhi_cntrl->mhi_dev->dev, "destroy device for chan:%s\n",
		mhi_dev->chan_name);

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