On 21.01.2020 15:36, Kirill Tkhai wrote: > On 21.01.2020 15:24, Mike Snitzer wrote: >> On Tue, Jan 21 2020 at 5:42am -0500, >> Kirill Tkhai <ktkhai@xxxxxxxxxxxxx> wrote: >> >>> Since dm inherits limits from underlining block devices, >>> this patch directly disables max_allocate_sectors for dm >>> till full allocation support is implemented. >>> >>> This prevents high-level primitives (generic_make_request_checks(), >>> __blkdev_issue_write_zeroes(), ...) from sending REQ_ALLOCATE >>> requests. >>> >>> Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx> >>> --- >>> drivers/md/dm-table.c | 2 ++ >>> drivers/md/md.h | 1 + >>> 2 files changed, 3 insertions(+) >> >> You're mixing DM and MD changes in the same patch. >> >> But I'm wondering if it might be best to set this default for stacking >> devices in blk_set_stacking_limits()? >> >> And then it is up to each stacking driver to override as needed. > > Hm. Sound like a good idea. This "lim->max_allocate_sectors = 0" in blk_set_stacking_limits() > should work for dm's dm_calculate_queue_limits(), since it calls blk_stack_limits(), which is: > > t->max_allocate_sectors = min(t->max_allocate_sectors, > b->max_allocate_sectors); > > Could you please tell is this fix is also enough for md? It looks like it's enough since queue defaults are set in md_alloc()->blk_set_stacking_limits(). In case of we set "max_allocate_sectors = 0", in further it can be changed only manually, but nobody does this. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
