From 4862c8861d902d43645a493e441c4478be1c6c44 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 29 Apr 2025 18:50:17 +0200 Subject: dm: Allow .prepare_ioctl to handle ioctls directly This adds a 'bool *forward' parameter to .prepare_ioctl, which allows device mapper targets to accept ioctls to themselves instead of the underlying device. If the target already fully handled the ioctl, it sets *forward to false and device mapper won't forward it to the underlying device any more. In order for targets to actually know what the ioctl is about and how to handle it, pass also cmd and arg. As long as targets restrict themselves to interpreting ioctls of type DM_IOCTL, this is a backwards compatible change because previously, any such ioctl would have been passed down through all device mapper layers until it reached a device that can't understand the ioctl and would return an error. Signed-off-by: Kevin Wolf Reviewed-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka --- include/linux/device-mapper.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'include/linux/device-mapper.h') diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index bcc6d7b69470..cb95951547ab 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -93,7 +93,14 @@ typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, typedef int (*dm_message_fn) (struct dm_target *ti, unsigned int argc, char **argv, char *result, unsigned int maxlen); -typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti, struct block_device **bdev); +/* + * Called with *forward == true. If it remains true, the ioctl should be + * forwarded to bdev. If it is reset to false, the target already fully handled + * the ioctl and the return value is the return value for the whole ioctl. + */ +typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti, struct block_device **bdev, + unsigned int cmd, unsigned long arg, + bool *forward); #ifdef CONFIG_BLK_DEV_ZONED typedef int (*dm_report_zones_fn) (struct dm_target *ti, -- cgit