On Wed 02-05-18 13:32:28, Darrick J. Wong wrote:
> +/*
> + * Collect physical extents for this swap file. Physical extents reported to
> + * the swap code must be trimmed to align to a page boundary. The logical
> + * offset within the file is irrelevant since the swapfile code maps logical
> + * page numbers of the swap device to the physical page-aligned extents.
> + */
> +static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi)
> +{
> + struct iomap *iomap = &isi->iomap;
> + unsigned long nr_pages;
> + uint64_t first_ppage;
> + uint64_t first_ppage_reported;
> + uint64_t last_ppage;
> + int error;
> +
> + /*
> + * Round the start up and the length down so that the physical
> + * extent aligns to a page boundary.
> + */
> + first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT;
> + last_ppage = (ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >>
> + PAGE_SHIFT) - 1;
> + nr_pages = last_ppage - first_ppage + 1;
So if I pass in iomap->addr = 1k, iomap->length = 1k, I get first_ppage =
1, last_ppage = -1, and thus nr_pages = (unsigned long)-1 and the test
below does not hit although it should. I think you need there
if (first_ppage > last_ppage)
Otherwise the patch looks good to me.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
