From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kQ66A-0005n1-U1 for barebox@lists.infradead.org; Wed, 07 Oct 2020 09:51:06 +0000 From: Ahmad Fatoum Date: Wed, 7 Oct 2020 11:50:52 +0200 Message-Id: <20201007095058.22950-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH v2 1/7] driver: introduce less error-prone dev_get_drvdata alternative To: barebox@lists.infradead.org Cc: Ahmad Fatoum We use dev_get_drvdata to get the driver match data associated with a device. This has two shortcomings: - Linux has dev_get_drvdata too, which returns a private pointer for driver specific info to associate with a device. We use dev->priv (or more often container_of) for that in barebox instead - It nearly always involves a cast to a double pointer, which is error-prone as size and alignment match need to be ensured on the programmer's part and can easily be gotten wrong: enum dev_type type; dev_get_drvdata(dev, (const void **)&type); // UB! Add a new function that instead of using a double pointer argument, returns the pointer directly: - For normal pointer driver data, no cast is necessary - For integer driver data casted to a pointer for storage, the cast is still necessary, but it's only a single pointer this way Signed-off-by: Ahmad Fatoum --- v1 -> v2: - Changed second patch to use pointer instead of enum in match data (Sascha) - Changed third and fourth patch to return error on match with driver name instead of assuming to be compatible with a default type. --- drivers/base/driver.c | 11 +++++++++++ include/driver.h | 18 ++++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/drivers/base/driver.c b/drivers/base/driver.c index 412db6c40699..3205bbc3c33b 100644 --- a/drivers/base/driver.c +++ b/drivers/base/driver.c @@ -500,3 +500,14 @@ int dev_get_drvdata(struct device_d *dev, const void **data) return -ENODEV; } + +const void *device_get_match_data(struct device_d *dev) +{ + if (dev->of_id_entry) + return dev->of_id_entry->data; + + if (dev->id_entry) + return (void *)dev->id_entry->driver_data; + + return NULL; +} diff --git a/include/driver.h b/include/driver.h index 1961ab6ed9ea..e2886d051d4f 100644 --- a/include/driver.h +++ b/include/driver.h @@ -540,8 +540,26 @@ int devfs_create_partitions(const char *devname, #define DRV_OF_COMPAT(compat) \ IS_ENABLED(CONFIG_OFDEVICE) ? (compat) : NULL +/** + * dev_get_drvdata - get driver match data associated with device + * @dev: device instance + * @data: pointer to void *, where match data is stored + * + * Returns 0 on success and error code otherwise. + * + * DEPRECATED: use device_get_match_data instead, which avoids + * common pitfalls due to explicit pointer casts + */ int dev_get_drvdata(struct device_d *dev, const void **data); +/** + * device_get_match_data - get driver match data associated with device + * @dev: device instance + * + * Returns match data on success and NULL otherwise + */ +const void *device_get_match_data(struct device_d *dev); + int device_match_of_modalias(struct device_d *dev, struct driver_d *drv); #endif /* DRIVER_H */ -- 2.28.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox