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Commit 068f4070 authored by David Brownell's avatar David Brownell Committed by Linus Torvalds
Browse files

SPI: use mutex not semaphore 



Make spi_write_then_read() use a mutex not a binary semaphore.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f8fcc933

drivers/spi/spi.c

+3 −3
Original line number Diff line number Diff line
@@ -589,7 +589,7 @@ int spi_write_then_read(struct spi_device *spi, 
		const u8 *txbuf, unsigned n_tx,

		u8 *rxbuf, unsigned n_rx)

{

	static DECLARE_MUTEX(lock);

	static DEFINE_MUTEX(lock);



	int			status;

	struct spi_message	message;
@@ -615,7 +615,7 @@ int spi_write_then_read(struct spi_device *spi, 
	}



	/* ... unless someone else is using the pre-allocated buffer */

	if (down_trylock(&lock)) {

	if (!mutex_trylock(&lock)) {

		local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);

		if (!local_buf)

			return -ENOMEM;
@@ -634,7 +634,7 @@ int spi_write_then_read(struct spi_device *spi, 
	}



	if (x[0].tx_buf == buf)

		up(&lock);

		mutex_unlock(&lock);

	else

		kfree(local_buf);