spi: fix possible deadlock between internal bus locks and bus_lock_flag
From: Heiko Stuebner <heiko@...> Date: Fri, 18 Mar 2016 00:12:03 +0100
Commit-Message
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@...>
Patch-Comment
changes in v2: - move the second check from __spi_pump_messages to its calling functions spi_pump_messages and __spi_sync as suggested by Vignesh drivers/spi/spi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
Statistics
- 2 lines added
- 2 lines removed
Changes
------------------------------ drivers/spi/spi.c -------------------------------
index de2f2f9..0239b45 100644
@@ -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, 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, spi->master->bus_lock_flag);
}
EXPORT_SYMBOL_GPL(spi_sync);