From ca52aa4c60f76566601b42e935b8a78f0fb4f8eb Mon Sep 17 00:00:00 2001 From: David Lechner Date: Mon, 8 Jul 2024 20:05:29 -0500 Subject: spi: add defer_optimize_message controller flag Adding spi_optimize_message() broke the spi-mux driver because it calls spi_async() from it's transfer_one_message() callback. This resulted in passing an incorrectly optimized message to the controller. For example, if the underlying controller has an optimize_message() callback, this would have not been called and can cause a crash when the underlying controller driver tries to transfer the message. Also, since the spi-mux driver swaps out the controller pointer by replacing msg->spi, __spi_unoptimize_message() was being called with a different controller than the one used in __spi_optimize_message(). This could cause a crash when attempting to free the message resources when __spi_unoptimize_message() is called in spi_finalize_current_message() since it is being called with a controller that did not allocate the resources. This is fixed by adding a defer_optimize_message flag for controllers. This flag causes all of the spi_[maybe_][un]optimize_message() calls to be a no-op (other than attaching a pointer to the spi device to the message). This allows the spi-mux driver to pass an unmodified message to spi_async() in spi_mux_transfer_one_message() after the spi device has been swapped out. This causes __spi_optimize_message() and __spi_unoptimize_message() to be called only once per message and with the correct/same controller in each case. Reported-by: Oleksij Rempel Closes: https://lore.kernel.org/linux-spi/Zn6HMrYG2b7epUxT@pengutronix.de/ Reported-by: Marc Kleine-Budde Closes: https://lore.kernel.org/linux-spi/20240628-awesome-discerning-bear-1621f9-mkl@pengutronix.de/ Fixes: 7b1d87af14d9 ("spi: add spi_optimize_message() APIs") Signed-off-by: David Lechner Link: https://patch.msgid.link/20240708-spi-mux-fix-v1-2-6c8845193128@baylibre.com Signed-off-by: Mark Brown --- drivers/spi/spi-mux.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/spi/spi-mux.c') diff --git a/drivers/spi/spi-mux.c b/drivers/spi/spi-mux.c index 5d72e3d59df8..f4b619cc2657 100644 --- a/drivers/spi/spi-mux.c +++ b/drivers/spi/spi-mux.c @@ -164,6 +164,7 @@ static int spi_mux_probe(struct spi_device *spi) ctlr->bus_num = -1; ctlr->dev.of_node = spi->dev.of_node; ctlr->must_async = true; + ctlr->defer_optimize_message = true; ret = devm_spi_register_controller(&spi->dev, ctlr); if (ret) -- cgit