6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: David Lechner dlechner@baylibre.com
[ Upstream commit ca52aa4c60f76566601b42e935b8a78f0fb4f8eb ]
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 o.rempel@pengutronix.de Closes: https://lore.kernel.org/linux-spi/Zn6HMrYG2b7epUxT@pengutronix.de/ Reported-by: Marc Kleine-Budde mkl@pengutronix.de Closes: https://lore.kernel.org/linux-spi/20240628-awesome-discerning-bear-1621f9-mk... Fixes: 7b1d87af14d9 ("spi: add spi_optimize_message() APIs") Signed-off-by: David Lechner dlechner@baylibre.com Link: https://patch.msgid.link/20240708-spi-mux-fix-v1-2-6c8845193128@baylibre.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-mux.c | 1 + drivers/spi/spi.c | 18 +++++++++++++++++- include/linux/spi/spi.h | 4 ++++ 3 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/spi-mux.c b/drivers/spi/spi-mux.c index bd988f53753e2..031b5795d1060 100644 --- a/drivers/spi/spi-mux.c +++ b/drivers/spi/spi-mux.c @@ -162,6 +162,7 @@ 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) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index a1958e86f75c8..9304fd03bf764 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2137,7 +2137,8 @@ static void __spi_unoptimize_message(struct spi_message *msg) */ static void spi_maybe_unoptimize_message(struct spi_message *msg) { - if (!msg->pre_optimized && msg->optimized) + if (!msg->pre_optimized && msg->optimized && + !msg->spi->controller->defer_optimize_message) __spi_unoptimize_message(msg); }
@@ -4285,6 +4286,11 @@ static int __spi_optimize_message(struct spi_device *spi, static int spi_maybe_optimize_message(struct spi_device *spi, struct spi_message *msg) { + if (spi->controller->defer_optimize_message) { + msg->spi = spi; + return 0; + } + if (msg->pre_optimized) return 0;
@@ -4315,6 +4321,13 @@ int spi_optimize_message(struct spi_device *spi, struct spi_message *msg) { int ret;
+ /* + * Pre-optimization is not supported and optimization is deferred e.g. + * when using spi-mux. + */ + if (spi->controller->defer_optimize_message) + return 0; + ret = __spi_optimize_message(spi, msg); if (ret) return ret; @@ -4341,6 +4354,9 @@ EXPORT_SYMBOL_GPL(spi_optimize_message); */ void spi_unoptimize_message(struct spi_message *msg) { + if (msg->spi->controller->defer_optimize_message) + return; + __spi_unoptimize_message(msg); msg->pre_optimized = false; } diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index c459809efee4f..64a4deb18dd00 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -532,6 +532,9 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch * @queue_empty: signal green light for opportunistically skipping the queue * for spi_sync transfers. * @must_async: disable all fast paths in the core + * @defer_optimize_message: set to true if controller cannot pre-optimize messages + * and needs to defer the optimization step until the message is actually + * being transferred * * Each SPI controller can communicate with one or more @spi_device * children. These make a small bus, sharing MOSI, MISO and SCK signals @@ -775,6 +778,7 @@ struct spi_controller { /* Flag for enabling opportunistic skipping of the queue in spi_sync */ bool queue_empty; bool must_async; + bool defer_optimize_message; };
static inline void *spi_controller_get_devdata(struct spi_controller *ctlr)