mhi: Fix double dma free

mhi_deinit_chan_ctxt functionthat takes care of unitializing channel
resources, including unmapping coherent MHI areas, can be called
from different path in case of controller unregistering/removal:
 - From a client driver remove callback, via mhi_unprepare_channel
 - From mhi_driver_remove that unitialize all channels

mhi_driver_remove()
|-> driver->remove()
|    |-> mhi_unprepare_channel()
|        |-> mhi_deinit_chan_ctxt()
|...
|-> mhi_deinit_chan_ctxt()

This leads to double dma freeing...

Fix that by preventing deinit for already uninitialized channel.

Link: https://lore.kernel.org/r/1612894264-15956-1-git-send-email-loic.poulain@linaro.org
Fixes: a7f422f2f89e ("bus: mhi: Fix channel close issue on driver remove")
Reported-by: Kalle Valo <kvalo@codeaurora.org>
Tested-by: Kalle Valo <kvalo@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210210082538.2494-2-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index aa575d3..be4eebb 100644 (file)
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -557,6 +557,9 @@ void mhi_deinit_chan_ctxt(struct mhi_controller *mhi_cntrl,
        tre_ring = &mhi_chan->tre_ring;
        chan_ctxt = &mhi_cntrl->mhi_ctxt->chan_ctxt[mhi_chan->chan];
 
+       if (!chan_ctxt->rbase) /* Already uninitialized */
+               return;
+
        mhi_free_coherent(mhi_cntrl, tre_ring->alloc_size,
                          tre_ring->pre_aligned, tre_ring->dma_handle);
        vfree(buf_ring->base);