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[058/108] spi: bitbang: Let spi_bitbang_start() take a reference to master

Message ID 1386922983-22135-59-git-send-email-daniel.sangorrin@toshiba.co.jp (mailing list archive)
State New, archived
Headers show

Commit Message

Daniel Sangorrin Dec. 13, 2013, 8:22 a.m. UTC 
From: Axel Lin <axel.lin@ingics.com>

Many drivers that use bitbang library have a leak on probe error paths.
This is because once a spi_master_get() call succeeds, we need an additional
spi_master_put() call to free the memory.

Fix this issue by moving the code taking a reference to master to
spi_bitbang_start(), so spi_bitbang_start() will take a reference to master on
success. With this change, the caller is responsible for calling
spi_bitbang_stop() to decrement the reference and spi_master_put() as
counterpart of spi_alloc_master() to prevent a memory leak.

So now we have below patten for drivers using bitbang library:

probe:
spi_alloc_master        -> Init reference count to 1
spi_bitbang_start       -> Increment reference count
remove:
spi_bitbang_stop        -> Decrement reference count
spi_master_put          -> Decrement reference count (reference count reaches 0)

Fixup all users accordingly.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Suggested-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
(cherry picked from commit 94c69f765f1b4a658d96905ec59928e3e3e07e6a)
Signed-off-by: Daniel Sangorrin <daniel.sangorrin@toshiba.co.jp>
Signed-off-by: Yoshitake Kobayashi <yoshitake.kobayashi@toshiba.co.jp>
---
 drivers/spi/spi-xilinx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox

Patch

diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index 0bf1b2c..ec3a83f 100644
--- a/drivers/spi/spi-xilinx.c
+++ b/drivers/spi/spi-xilinx.c
@@ -372,7 +372,7 @@  static int xilinx_spi_probe(struct platform_device *pdev)
 	master->mode_bits = SPI_CPOL | SPI_CPHA;
 
 	xspi = spi_master_get_devdata(master);
-	xspi->bitbang.master = spi_master_get(master);
+	xspi->bitbang.master = master;
 	xspi->bitbang.chipselect = xilinx_spi_chipselect;
 	xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
 	xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;