[PATCH 5.4 34/84] spi: Cleanup on failure of initial setup

Greg Kroah-Hartman
2021-06-14T10:58:43Z

From: Lukas Wunner <lukas@wunner.de>

[ Upstream commit 2ec6f20b33eb4f62ab90bdcd620436c883ec3af6 ]

Commit c7299fea6769 ("spi: Fix spi device unregister flow") changed the
SPI core's behavior if the ->setup() hook returns an error upon adding
an spi_device: Before, the ->cleanup() hook was invoked to free any
allocations that were made by ->setup(). With the commit, that's no
longer the case, so the ->setup() hook is expected to free the
allocations itself.

I've identified 5 drivers which depend on the old behavior and am fixing
them up hereinafter: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c
spi-omap2-mcspi.c spi-pxa2xx.c

Importantly, ->setup() is not only invoked on spi_device *addition*:
It may subsequently be called to *change* SPI parameters. If changing
these SPI parameters fails, freeing memory allocations would be wrong.
That should only be done if the spi_device is finally destroyed.
I am therefore using a bool "initial_setup" in 4 of the affected drivers
to differentiate between the invocation on *adding* the spi_device and
any subsequent invocations: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c
spi-omap2-mcspi.c

In spi-pxa2xx.c, it seems the ->setup() hook can only fail on spi_device
addition, not any subsequent calls. It therefore doesn't need the bool.

It's worth noting that 5 other drivers already perform a cleanup if the
->setup() hook fails. Before c7299fea6769, they caused a double-free
if ->setup() failed on spi_device addition. Since the commit, they're
fine. These drivers are: spi-mpc512x-psc.c spi-pl022.c spi-s3c64xx.c
spi-st-ssc4.c spi-tegra114.c

(spi-pxa2xx.c also already performs a cleanup, but only in one of
several error paths.)

Fixes: c7299fea6769 ("spi: Fix spi device unregister flow")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Saravana Kannan <saravanak@google.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> # pxa2xx
Link: https://lore.kernel.org/r/f76a0599469f265b69c371538794101fa37b5536.1622149321.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-bitbang.c | 18 ++++++++++++----
drivers/spi/spi-fsl-spi.c | 4 ++++
drivers/spi/spi-omap-uwire.c | 9 +++++++-
drivers/spi/spi-omap2-mcspi.c | 39 +++++++++++++++++++++--------------
drivers/spi/spi-pxa2xx.c | 9 +++++++-
5 files changed, 57 insertions(+), 22 deletions(-)

diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c
index d84e22dd6f9f..7d61a3b71ee5 100644
--- a/drivers/spi/spi-bitbang.c
+++ b/drivers/spi/spi-bitbang.c
@@ -181,6 +181,8 @@ int spi_bitbang_setup(struct spi_device *spi)
{
struct spi_bitbang_cs *cs = spi->controller_state;
struct spi_bitbang *bitbang;
+ bool initial_setup = false;
+ int retval;

bitbang = spi_master_get_devdata(spi->master);

@@ -189,22 +191,30 @@ int spi_bitbang_setup(struct spi_device *spi)
if (!cs)
return -ENOMEM;
spi->controller_state = cs;
+ initial_setup = true;
}

/* per-word shift register access, in hardware or bitbanging */
cs->txrx_word = bitbang->txrx_word[spi->mode & (SPI_CPOL|SPI_CPHA)];
- if (!cs->txrx_word)
- return -EINVAL;
+ if (!cs->txrx_word) {
+ retval = -EINVAL;
+ goto err_free;
+ }

if (bitbang->setup_transfer) {
- int retval = bitbang->setup_transfer(spi, NULL);
+ retval = bitbang->setup_transfer(spi, NULL);
if (retval < 0)
- return retval;
+ goto err_free;
}

dev_dbg(&spi->dev, "%s, %u nsec/bit\n", __func__, 2 * cs->nsecs);

return 0;
+
+err_free:
+ if (initial_setup)
+ kfree(cs);
+ return retval;
}
EXPORT_SYMBOL_GPL(spi_bitbang_setup);

diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c
index 18a93a2854d8..02b999d48ca1 100644
--- a/drivers/spi/spi-fsl-spi.c
+++ b/drivers/spi/spi-fsl-spi.c
@@ -442,6 +442,7 @@ static int fsl_spi_setup(struct spi_device *spi)
{
struct mpc8xxx_spi *mpc8xxx_spi;
struct fsl_spi_reg *reg_base;
+ bool initial_setup = false;
int retval;
u32 hw_mode;
struct spi_mpc8xxx_cs *cs = spi_get_ctldata(spi);
@@ -454,6 +455,7 @@ static int fsl_spi_setup(struct spi_device *spi)
if (!cs)
return -ENOMEM;
spi_set_ctldata(spi, cs);
+ initial_setup = true;
}
mpc8xxx_spi = spi_master_get_devdata(spi->master);

@@ -477,6 +479,8 @@ static int fsl_spi_setup(struct spi_device *spi)
retval = fsl_spi_setup_transfer(spi, NULL);
if (retval < 0) {
cs->hw_mode = hw_mode; /* Restore settings */
+ if (initial_setup)
+ kfree(cs);
return retval;
}

diff --git a/drivers/spi/spi-omap-uwire.c b/drivers/spi/spi-omap-uwire.c
index ce8dbdbce312..85ee907e28f9 100644
--- a/drivers/spi/spi-omap-uwire.c
+++ b/drivers/spi/spi-omap-uwire.c
@@ -424,15 +424,22 @@ done:
static int uwire_setup(struct spi_device *spi)
{
struct uwire_state *ust = spi->controller_state;
+ bool initial_setup = false;
+ int status;

if (ust == NULL) {
ust = kzalloc(sizeof(*ust), GFP_KERNEL);
if (ust == NULL)
return -ENOMEM;
spi->controller_state = ust;
+ initial_setup = true;
}

- return uwire_setup_transfer(spi, NULL);
+ status = uwire_setup_transfer(spi, NULL);
+ if (status && initial_setup)
+ kfree(ust);
+
+ return status;
}

static void uwire_cleanup(struct spi_device *spi)
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 7646b4b56bed..38f4be209234 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -1043,8 +1043,25 @@ static void omap2_mcspi_release_dma(struct spi_master *master)
}
}

+static void omap2_mcspi_cleanup(struct spi_device *spi)
+{
+ struct omap2_mcspi_cs *cs;
+
+ if (spi->controller_state) {
+ /* Unlink controller state from context save list */
+ cs = spi->controller_state;
+ list_del(&cs->node);
+
+ kfree(cs);
+ }
+
+ if (gpio_is_valid(spi->cs_gpio))
+ gpio_free(spi->cs_gpio);
+}
+
static int omap2_mcspi_setup(struct spi_device *spi)
{
+ bool initial_setup = false;
int ret;
struct omap2_mcspi *mcspi = spi_master_get_devdata(spi->master);
struct omap2_mcspi_regs *ctx = &mcspi->ctx;
@@ -1062,6 +1079,7 @@ static int omap2_mcspi_setup(struct spi_device *spi)
spi->controller_state = cs;
/* Link this to context save list */
list_add_tail(&cs->node, &ctx->cs);
+ initial_setup = true;

if (gpio_is_valid(spi->cs_gpio)) {
ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev));
@@ -1077,33 +1095,22 @@ static int omap2_mcspi_setup(struct spi_device *spi)
ret = pm_runtime_get_sync(mcspi->dev);
if (ret < 0) {
pm_runtime_put_noidle(mcspi->dev);
+ if (initial_setup)
+ omap2_mcspi_cleanup(spi);

return ret;
}

ret = omap2_mcspi_setup_transfer(spi, NULL);
+ if (ret && initial_setup)
+ omap2_mcspi_cleanup(spi);
+
pm_runtime_mark_last_busy(mcspi->dev);
pm_runtime_put_autosuspend(mcspi->dev);

return ret;
}

-static void omap2_mcspi_cleanup(struct spi_device *spi)
-{
- struct omap2_mcspi_cs *cs;
-
- if (spi->controller_state) {
- /* Unlink controller state from context save list */
- cs = spi->controller_state;
- list_del(&cs->node);
-
- kfree(cs);
- }
-
- if (gpio_is_valid(spi->cs_gpio))
- gpio_free(spi->cs_gpio);
-}
-
static irqreturn_t omap2_mcspi_irq_handler(int irq, void *data)
{
struct omap2_mcspi *mcspi = data;
diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index f5a10a94f156..e32d51f27944 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -1241,6 +1241,8 @@ static int setup_cs(struct spi_device *spi, struct chip_data *chip,
chip->gpio_cs_inverted = spi->mode & SPI_CS_HIGH;

err = gpiod_direction_output(gpiod, !chip->gpio_cs_inverted);
+ if (err)
+ gpiod_put(chip->gpiod_cs);
}

return err;
@@ -1254,6 +1256,7 @@ static int setup(struct spi_device *spi)
struct driver_data *drv_data =
spi_controller_get_devdata(spi->controller);
uint tx_thres, tx_hi_thres, rx_thres;
+ int err;

switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
@@ -1400,7 +1403,11 @@ static int setup(struct spi_device *spi)
if (drv_data->ssp_type == CE4100_SSP)
return 0;

- return setup_cs(spi, chip, chip_info);
+ err = setup_cs(spi, chip, chip_info);
+ if (err)
+ kfree(chip);
+
+ return err;
}

static void cleanup(struct spi_device *spi)
--
2.30.2