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: 49023d2e4ead ("spi: core: Fix deadlock when sending messages")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index de2f2f9..0239b45 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -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);