From: Bartosz Golaszewski Date: Thu, 22 Sep 2022 09:51:24 +0000 (+0200) Subject: gpiolib: cdev: add fdinfo output for line request file descriptors X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0ae3109a839192920f09338e9abc4d5321107865;p=linux.git gpiolib: cdev: add fdinfo output for line request file descriptors Add fdinfo output for file descriptors created for user-space line requests in GPIO uAPI v2. The fdinfo file now contains the name of the GPIO chip that is the "parent" of the request as well as offsets of the lines requested. This allows user-space to parse the /proc/$PID/fdinfo entries and deduce the PID of the process that requested a specific line. Signed-off-by: Bartosz Golaszewski Reviewed-by: Kent Gibson --- diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index f8041d4898d19..01c15e9e6896b 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -1497,6 +1497,21 @@ static int linereq_release(struct inode *inode, struct file *file) return 0; } +#ifdef CONFIG_PROC_FS +static void linereq_show_fdinfo(struct seq_file *out, struct file *file) +{ + struct linereq *lr = file->private_data; + struct device *dev = &lr->gdev->dev; + u16 i; + + seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev)); + + for (i = 0; i < lr->num_lines; i++) + seq_printf(out, "gpio-line:\t%d\n", + gpio_chip_hwgpio(lr->lines[i].desc)); +} +#endif + static const struct file_operations line_fileops = { .release = linereq_release, .read = linereq_read, @@ -1507,6 +1522,9 @@ static const struct file_operations line_fileops = { #ifdef CONFIG_COMPAT .compat_ioctl = linereq_ioctl_compat, #endif +#ifdef CONFIG_PROC_FS + .show_fdinfo = linereq_show_fdinfo, +#endif }; static int linereq_create(struct gpio_device *gdev, void __user *ip)