On Wed, May 18, 2022 at 10:11:31AM -0700, Keith Busch wrote: > diff --git a/block/fops.c b/block/fops.c > index b9b83030e0df..d8537c29602f 100644 > --- a/block/fops.c > +++ b/block/fops.c > @@ -54,8 +54,9 @@ static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb, > struct bio bio; > ssize_t ret; > > - if ((pos | iov_iter_alignment(iter)) & > - (bdev_logical_block_size(bdev) - 1)) > + if ((pos | iov_iter_count(iter)) & (bdev_logical_block_size(bdev) - 1)) > + return -EINVAL; > + if (iov_iter_alignment(iter) & bdev_dma_alignment(bdev)) > return -EINVAL; The block layer makes a lot of assumptions that bios can be split at any bvec boundary. With this patch, bios whose length isn't a multiple of the logical block size can be generated by splitting, which isn't valid. Also some devices aren't compatible with logical blocks spanning bdevs at all. dm-crypt errors out in this case, for example. What am I missing? - Eric