On Thu, May 23, 2024 at 05:50:09PM +0200, Christoph Hellwig wrote: > On Thu, May 23, 2024 at 11:44:05AM -0400, Mike Snitzer wrote: > > a difference on larger IOs being formed (given it is virtual > > scsi_debug devices). > > > > In any case, we know I can reproduce with this scsi_debug-based mptest > > test and Marco has verified my fix resolves the issue on his FC > > multipath testbed. > > > > But I've just floated a patch to elevate the fix to block core (based > > on Ming's suggestion): > > https://patchwork.kernel.org/project/dm-devel/patch/Zk9i7V2GRoHxBPRu@xxxxxxxxxx/ > > I still think that is wrong. Unfortunately I can't actually reproduce > the issue locally, but I think we want sd to set the user_max_sectors > and stack if you want to see the limits propagated, i.e. the combined > patch below. In the longer run I need to get SCSI out of messing > with max_sectors directly, and the blk-mq stacking to stop looking > at it vs just the hardware limits (or just drop the check). This "works" but it doesn't safeguard blk_stack_limits() and blk_validate_limits() from other drivers that weren't trained to (ab)use max_user_sectors to get blk_validate_limits() to preserve the underlying device's max_sectors. But I suppose we can worry about any other similar issues if/when reported. Please send a proper patch to Jens so we can get this fixed for 6.10-rc1. Thanks. Acked-by: Mike Snitzer <snitzer@xxxxxxxxxx> > > diff --git a/block/blk-settings.c b/block/blk-settings.c > index a7fe8e90240a6e..7a672021daee6a 100644 > --- a/block/blk-settings.c > +++ b/block/blk-settings.c > @@ -611,6 +611,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, > unsigned int top, bottom, alignment, ret = 0; > > t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors); > + t->max_user_sectors = min_not_zero(t->max_user_sectors, > + b->max_user_sectors); > t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors); > t->max_dev_sectors = min_not_zero(t->max_dev_sectors, b->max_dev_sectors); > t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors, > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 332eb9dac22d91..f6c822c9cbd2d3 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -3700,8 +3700,10 @@ static int sd_revalidate_disk(struct gendisk *disk) > */ > if (sdkp->first_scan || > q->limits.max_sectors > q->limits.max_dev_sectors || > - q->limits.max_sectors > q->limits.max_hw_sectors) > + q->limits.max_sectors > q->limits.max_hw_sectors) { > q->limits.max_sectors = rw_max; > + q->limits.max_user_sectors = rw_max; > + } > > sdkp->first_scan = 0; > > >
