On Wed, Jun 4, 2025 at 12:24 AM Jens Axboe <axboe@xxxxxxxxx> wrote: > > On 6/3/25 12:47 PM, Caleb Sander Mateos wrote: > > blk_rq_integrity_map_user() creates the ubuf iter with ITER_DEST for > > write-direction operations and ITER_SOURCE for read-direction ones. > > This is backwards; writes use the user buffer as a source for metadata > > and reads use it as a destination. Switch to the rq_data_dir() helper, > > which maps writes to ITER_SOURCE (WRITE) and reads to ITER_DEST(READ). > > Was going to ask "how did this ever work without splats", but looks like > a fairly recent change AND it's for integrity which isn't widely used. > But it does show a gap in testing for sure. > Yes, you're absolutely right. blk_rq_integrity_map_user() is currently only used by nvme-passthru, and Keith recently added a test for that path [1]. As for the user block integrity interface in general — it’s been a bit tricky to write generic tests so far, mostly because there's no way to query the device's integrity capabilities from userspace. But that should become much easier once we have support for that via an ioctl[2]. [1] https://lore.kernel.org/io-uring/20250416162802.3614051-1-kbusch@xxxxxxxx/ [2] https://lore.kernel.org/all/20250527104237.2928-1-anuj20.g@xxxxxxxxxxx/
