spi: bitbang: Let spi_bitbang_start() take a reference to master
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>
diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index 8fbfe24..af2bb73 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -916,7 +916,7 @@
if (ret)
goto unmap_io;
- dspi->bitbang.master = spi_master_get(master);
+ dspi->bitbang.master = master;
if (dspi->bitbang.master == NULL) {
ret = -ENODEV;
goto irq_free;
@@ -925,7 +925,7 @@
dspi->clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(dspi->clk)) {
ret = -ENODEV;
- goto put_master;
+ goto irq_free;
}
clk_prepare_enable(dspi->clk);
@@ -1015,8 +1015,6 @@
free_clk:
clk_disable_unprepare(dspi->clk);
clk_put(dspi->clk);
-put_master:
- spi_master_put(master);
irq_free:
free_irq(dspi->irq, dspi);
unmap_io:
@@ -1024,7 +1022,7 @@
release_region:
release_mem_region(dspi->pbase, resource_size(r));
free_master:
- kfree(master);
+ spi_master_put(master);
err:
return ret;
}
@@ -1051,11 +1049,11 @@
clk_disable_unprepare(dspi->clk);
clk_put(dspi->clk);
- spi_master_put(master);
free_irq(dspi->irq, dspi);
iounmap(dspi->base);
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(dspi->pbase, resource_size(r));
+ spi_master_put(master);
return 0;
}