Commit 24c8cd1b authored Mar 18, 2016 by Heiko Stübner Committed by Mark Brown Mar 18, 2016

spi: fix possible deadlock between internal bus locks and bus_lock_flag



External users may use spi_bus_lock to get exclusive access. This will
also grab the bus_lock_mutex and may therefore result in a deadlock if
__spi_pump_messages also tries to get the mutex.

Therefore adapt spi_pump_messages as well as spi_sync to preset the
bus_locked parameter according to the master->bus_lock_flag.

Fixes: 49023d2e ("spi: core: Fix deadlock when sending messages")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

parent c508709b

drivers/spi/spi.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1209,7 +1209,7 @@ static void spi_pump_messages(struct kthread_work *work)
		struct spi_master *master =
		container_of(work, struct spi_master, pump_messages);

		__spi_pump_messages(master, true, false);
		__spi_pump_messages(master, true, master->bus_lock_flag);
		}

		static int spi_init_queue(struct spi_master *master)
		@@ -2853,7 +2853,7 @@ static int __spi_sync(struct spi_device spi, struct spi_message message,
		*/
		int spi_sync(struct spi_device spi, struct spi_message message)
		{
		return __spi_sync(spi, message, 0);
		return __spi_sync(spi, message, spi->master->bus_lock_flag);
		}
		EXPORT_SYMBOL_GPL(spi_sync);