Re: [PATCH 3/5] nvme: refactor namespace probing

Joel Granados
2022-07-20T08:35:06Z

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On Tue, Jul 19, 2022 at 04:37:03PM +0200, Christoph Hellwig wrote:
> On Tue, Jul 19, 2022 at 03:00:48PM +0200, Joel Granados wrote:
> > > +++ b/drivers/nvme/host/core.c
> > > @@ -2011,8 +2011,10 @@ static int nvme_update_ns_info_block(struct nvme_ns *ns,
> > >
> > > if (blk_queue_is_zoned(ns->queue)) {
> > > ret = nvme_revalidate_zones(ns);
> > > - if (ret && !nvme_first_scan(ns->disk))
> > > + if (ret && !nvme_first_scan(ns->disk)) {
> > > + kfree(id);
> > > return ret;
> > > + }
> > > }
> > >
> >
> > Should we also take care to hide the device?
> > As I read it the call to nvme_revalidate_zones can return a -ENODEV
> > (through blk_revalidate_disk_zones) which is the original condition to
> > hide the block device.
>
> Yes, I think we need something like the patch below folded in. This
> unfreezes before setting the hidden flag and setting the ns ready,
> but I can't see why we'd need it frozen for that.
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index bbdf0f95331f3..e6025f80744f6 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -2012,7 +2012,7 @@ static int nvme_update_ns_info_block(struct nvme_ns *ns,
> if (blk_queue_is_zoned(ns->queue)) {
> ret = nvme_revalidate_zones(ns);
> if (ret && !nvme_first_scan(ns->disk))
> - return ret;
> + goto out_free_id;
> }
>
> if (nvme_ns_head_multipath(ns->head)) {
> @@ -2029,6 +2029,8 @@ static int nvme_update_ns_info_block(struct nvme_ns *ns,
> return 0;
>
> out_unfreeze:
> + blk_mq_unfreeze_queue(ns->disk->queue);
> +out_free_id:
> /*
> * If probing fails due an unsupported feature, hide the block device,
> * but still allow other access.
> @@ -2038,7 +2040,6 @@ static int nvme_update_ns_info_block(struct nvme_ns *ns,
> set_bit(NVME_NS_READY, &ns->flags);
> ret = 0;
> }
> - blk_mq_unfreeze_queue(ns->disk->queue);
> kfree(id);
> return ret;
> }

Yes. And with unfreeze in its own goto, we can return with the
out_free_id on success. In this way we do not duplicate the 'kfree' line
and future uses of 'ret' will just work.
Something like this:

diff --git i/drivers/nvme/host/core.c w/drivers/nvme/host/core.c
index bbdf0f95331f..8359efbb1d29 100644
--- i/drivers/nvme/host/core.c
+++ w/drivers/nvme/host/core.c
@@ -2012,7 +2012,7 @@ static int nvme_update_ns_info_block(struct nvme_ns *ns,
if (blk_queue_is_zoned(ns->queue)) {
ret = nvme_revalidate_zones(ns);
if (ret && !nvme_first_scan(ns->disk))
- return ret;
+ goto out_free_id;
}

if (nvme_ns_head_multipath(ns->head)) {
@@ -2025,10 +2025,11 @@ static int nvme_update_ns_info_block(struct nvme_ns *ns,
disk_update_readahead(ns->head->disk);
blk_mq_unfreeze_queue(ns->head->disk->queue);
}
- kfree(id);
- return 0;
+ goto out_free_id;

out_unfreeze:
+ blk_mq_unfreeze_queue(ns->disk->queue);
+out_free_id:
/*
* If probing fails due an unsupported feature, hide the block device,
* but still allow other access.
@@ -2038,7 +2039,6 @@ static int nvme_update_ns_info_block(struct nvme_ns *ns,
set_bit(NVME_NS_READY, &ns->flags);
ret = 0;
}
- blk_mq_unfreeze_queue(ns->disk->queue);
kfree(id);
return ret;
}

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