On Wed, Mar 18, 2026 at 06:40:52PM +0100, Mikulas Patocka wrote: > On Wed, 18 Mar 2026, Keith Busch wrote: > > > But even then, the only thing I know of that really wants this has an > > offset that straddles two pages per block, so I never need more than 2 > > segments, and the inline scatterlist has four. There's just currently no > > way for the block layer to report a max-segments-per-block limit, so I'm > > including this patch to be consistent with the reportable limits. > > Can userspace use preadv/pwritev with many small iovecs on a file opened > for direct I/O?
Yes, I have several patches that were accepted last year to block and iomap that align direct-io memory requirements to the backing device's dma constraints. You can do dword aligned and sized vectored IO to a block device today if the block limits say its okay.
