On Wed, Jun 14, 2023 at 01:46:34PM +0200, Hannes Reinecke wrote:
> @@ -43,9 +43,11 @@ struct brd_device {
> */
> struct xarray brd_folios;
> u64 brd_nr_folios;
> + unsigned int brd_sector_shift;
> + unsigned int brd_sector_size;
> };
>
> -#define BRD_SECTOR_SHIFT(b) (PAGE_SHIFT - SECTOR_SHIFT)
> +#define BRD_SECTOR_SHIFT(b) ((b)->brd_sector_shift - SECTOR_SHIFT)
>
> static pgoff_t brd_sector_index(struct brd_device *brd, sector_t sector)
> {
> @@ -85,7 +87,7 @@ static int brd_insert_folio(struct brd_device *brd, sector_t sector, gfp_t gfp)
> {
> pgoff_t idx;
> struct folio *folio, *cur;
> - unsigned int rd_sector_order = get_order(PAGE_SIZE);
> + unsigned int rd_sector_order = get_order(brd->brd_sector_size);
Surely max(0, brd->brd_sector_shift - PAGE_SHIFT) ?
> @@ -346,6 +353,25 @@ static int brd_alloc(int i)
> return -ENOMEM;
> brd->brd_number = i;
> list_add_tail(&brd->brd_list, &brd_devices);
> + brd->brd_sector_shift = ilog2(rd_blksize);
> + if ((1ULL << brd->brd_sector_shift) != rd_blksize) {
> + pr_err("rd_blksize %d is not supported\n", rd_blksize);
Are you trying to require power-of-two here? We have is_power_of_2()
for that purpose.
