spi: Add cond_resched() in main message processing loop
When a controller has only PIO support it is very likely that we will
run into use cases where we spend a very large amount of time consuming
CPU. Code that does this should call cond_resched() every once in a
while to give other tasks more of a chance to run so do that in the main
SPI loop, the overhead is negligable if it's not needed.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index dcc6f6e..0b2bbf1 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1184,6 +1184,9 @@
return;
}
mutex_unlock(&master->bus_lock_mutex);
+
+ /* Prod the scheduler in case transfer_one() was busy waiting */
+ cond_resched();
}
/**