From 702a4879ec337463f858c8ab467482cce260bf18 Mon Sep 17 00:00:00 2001 From: Axel Lin Date: Tue, 10 Sep 2013 15:43:41 +0800 Subject: 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 Suggested-by: Uwe Kleine-Koenig Acked-by: Uwe Kleine-Koenig Signed-off-by: Mark Brown --- drivers/spi/spi-bitbang.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'drivers/spi/spi-bitbang.c') diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c index 8c11355dec23..0056623dfc6b 100644 --- a/drivers/spi/spi-bitbang.c +++ b/drivers/spi/spi-bitbang.c @@ -414,10 +414,16 @@ static int spi_bitbang_unprepare_hardware(struct spi_master *spi) * This routine registers the spi_master, which will process requests in a * dedicated task, keeping IRQs unblocked most of the time. To stop * processing those requests, call spi_bitbang_stop(). + * + * On success, this routine will take a reference to master. 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. */ int spi_bitbang_start(struct spi_bitbang *bitbang) { struct spi_master *master = bitbang->master; + int ret; if (!master || !bitbang->chipselect) return -EINVAL; @@ -449,7 +455,11 @@ int spi_bitbang_start(struct spi_bitbang *bitbang) /* driver may get busy before register() returns, especially * if someone registered boardinfo for devices */ - return spi_register_master(master); + ret = spi_register_master(spi_master_get(master)); + if (ret) + spi_master_put(master); + + return 0; } EXPORT_SYMBOL_GPL(spi_bitbang_start); -- cgit From cff93c58f7a99b3bf2fc3b343a1b6ca0546120da Mon Sep 17 00:00:00 2001 From: Jingoo Han Date: Mon, 14 Oct 2013 10:33:38 +0900 Subject: spi: bitbang: Fix checkpatch issue Fix the following checkpatch warnings WARNING: sizeof *cs should be sizeof(*cs) WARNING: please, no space before tabs WARNING: space prohibited between function name and open parenthesis '(' WARNING: line over 80 characters Signed-off-by: Jingoo Han Signed-off-by: Mark Brown --- drivers/spi/spi-bitbang.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'drivers/spi/spi-bitbang.c') diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c index 0056623dfc6b..bd222f6b677d 100644 --- a/drivers/spi/spi-bitbang.c +++ b/drivers/spi/spi-bitbang.c @@ -191,7 +191,7 @@ int spi_bitbang_setup(struct spi_device *spi) bitbang = spi_master_get_devdata(spi->master); if (!cs) { - cs = kzalloc(sizeof *cs, GFP_KERNEL); + cs = kzalloc(sizeof(*cs), GFP_KERNEL); if (!cs) return -ENOMEM; spi->controller_state = cs; @@ -258,7 +258,7 @@ static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t) static int spi_bitbang_prepare_hardware(struct spi_master *spi) { - struct spi_bitbang *bitbang; + struct spi_bitbang *bitbang; unsigned long flags; bitbang = spi_master_get_devdata(spi); @@ -273,7 +273,7 @@ static int spi_bitbang_prepare_hardware(struct spi_master *spi) static int spi_bitbang_transfer_one(struct spi_master *master, struct spi_message *m) { - struct spi_bitbang *bitbang; + struct spi_bitbang *bitbang; unsigned nsecs; struct spi_transfer *t = NULL; unsigned cs_change; @@ -292,7 +292,7 @@ static int spi_bitbang_transfer_one(struct spi_master *master, cs_change = 1; status = 0; - list_for_each_entry (t, &m->transfers, transfer_list) { + list_for_each_entry(t, &m->transfers, transfer_list) { /* override speed or wordsize? */ if (t->speed_hz || t->bits_per_word) @@ -349,7 +349,8 @@ static int spi_bitbang_transfer_one(struct spi_master *master, if (t->delay_usecs) udelay(t->delay_usecs); - if (cs_change && !list_is_last(&t->transfer_list, &m->transfers)) { + if (cs_change && + !list_is_last(&t->transfer_list, &m->transfers)) { /* sometimes a short mid-message deselect of the chip * may be needed to terminate a mode or command */ @@ -378,7 +379,7 @@ static int spi_bitbang_transfer_one(struct spi_master *master, static int spi_bitbang_unprepare_hardware(struct spi_master *spi) { - struct spi_bitbang *bitbang; + struct spi_bitbang *bitbang; unsigned long flags; bitbang = spi_master_get_devdata(spi); -- cgit