Re: [PATCH 07/19] block: simplify bio_map_kern

Christoph Hellwig
2025-05-02T07:05:43Z

On Fri, May 02, 2025 at 03:56:08AM +0900, Damien Le Moal wrote:
> > - unsigned long kaddr = (unsigned long)data;
> > - unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
> > - unsigned long start = kaddr >> PAGE_SHIFT;
> > - const int nr_pages = end - start;
> > - bool is_vmalloc = is_vmalloc_addr(data);
> > - struct page *page;
> > - int offset, i;
> > + unsigned int nr_vecs = bio_add_max_vecs(data, len);
> > struct bio *bio;
> >
> > - bio = bio_kmalloc(nr_pages, gfp_mask);
> > + bio = bio_kmalloc(nr_vecs, gfp_mask);
>
> This may also fail if nr_vecs is larger than UIO_MAXIOV, in which case, the
> ENOMEM error may not really be appropriate. I guess we can sort this out
> separately though.

Yeah. It's also existing behavior, so no real change here.