Hello friends, here's an RFC for a generic implementation of the FITRIM ioctl: * introduce a new file_operation call vector for fstrim * move the generic pieces (eg. cap check, copy from/to userland, etc) into a generic implementation that then calls into the fileop * passing to the old ioctl fileop when fstrim op is NULL * convert a few fs'es to the new schema Rationale: it seems that all file systems implement generic stuff like permission checks and buffer copy from/to userspace, all on their own. We already have a common place for generic ioctl() handling (do_vfs_ioctl). I feel its time for factoring this out the common fstrim pieces, too. The first patch of this series introduces a new file_operation and calls it on FITRIM (from do_vfs_ioctl) if it's set - otherwise just passes the ioctl to file_ioctl(), as it had been before. So, this only becomes active on a fs thats converted to the new file_operation. Subsequent patches do the conversion for a few file systems. Note this is just an RFC, don't apply it - there might still be bugs in there. have fun, --mtx
