On Mon, Dec 04, 2023 at 11:19:20AM +0800, Ming Lei wrote: > On Fri, Sep 29, 2023 at 10:27:07AM +0000, John Garry wrote: > > We rely the block layer always being able to send a bio of size > > atomic_write_unit_max without being required to split it due to request > > queue or other bio limits. > > > > A bio may contain min(BIO_MAX_VECS, limits->max_segments) vectors, > > and each vector is at worst case the device logical block size from > > direct IO alignment requirement. > > Both unit_max and unit_min are applied to FS bio, which is built over > single userspace buffer, so only the 1st and last vector can include Actually it isn't true for pwritev, and sorry for the noise. Thanks, Ming