From: Christoph Hellwig <hch@lst.de>
To: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Cc: kbusch@kernel.org, hch@lst.de, linux-nvme@lists.infradead.org,
sagi@grimberg.me
Subject: Re: [PATCH V2 2/2] nvmet: use xarray for ctrl ns storing
Date: Wed, 1 Jul 2020 08:08:20 +0200 [thread overview]
Message-ID: <20200701060820.GA28214@lst.de> (raw)
In-Reply-To: <20200701022517.6738-3-chaitanya.kulkarni@wdc.com>
Ok, for the target I can see how this makes sense unlike the host.
Comments below:
> - u64 host_reads = 0, host_writes = 0;
> u64 data_units_read = 0, data_units_written = 0;
> - struct nvmet_ns *ns;
> + u64 host_reads = 0, host_writes = 0;
> struct nvmet_ctrl *ctrl;
> + struct nvmet_ns *ns;
> + unsigned long idx;
Please don't randomly reorder the variable declarations. Same for
later function.
> diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
> index cea7c3834021..d14edaa22ad5 100644
> --- a/drivers/nvme/target/core.c
> +++ b/drivers/nvme/target/core.c
> @@ -10,6 +10,9 @@
> #include <linux/pci-p2pdma.h>
> #include <linux/scatterlist.h>
>
> +#include "../host/nvme.h"
> +#undef CREATE_TRACE_POINTS
We really shoud not include the host nvme.h in the target code. What
are you trying to get from it?
> static unsigned int nvmet_max_nsid(struct nvmet_subsys *subsys)
> {
> - struct nvmet_ns *ns;
> + struct nvmet_ns *cur;
> + unsigned long idx;
> + unsigned long nsid;
>
> - if (list_empty(&subsys->namespaces))
> + if (xa_empty(&subsys->namespaces))
> return 0;
>
> - ns = list_last_entry(&subsys->namespaces, struct nvmet_ns, dev_link);
> - return ns->nsid;
> + xa_for_each(&subsys->namespaces, idx, cur)
> + nsid = cur->nsid;
> +
> + return nsid;
No need for the xa_empty here. I also forwarded a question to Matthew
if there is a better way to find the highest index.
> struct nvmet_ns *nvmet_find_namespace(struct nvmet_ctrl *ctrl, __le32 nsid)
> {
> + XA_STATE(xas, &ctrl->subsys->namespaces, le32_to_cpu(nsid));
> + struct nvmet_ns *ns = NULL;
>
> rcu_read_lock();
> + do {
> + ns = xas_load(&xas);
> + if (xa_is_zero(ns))
> + ns = NULL;
> + } while (xas_retry(&xas, ns));
> if (ns)
> percpu_ref_get(&ns->ref);
> rcu_read_unlock();
Why doesn't this use xa_load?
> + ret = xa_insert(&subsys->namespaces, ns->nsid, ns, GFP_KERNEL);
> + if (ret) {
> + switch (ret) {
> + case -ENOMEM:
> + pr_err("xa insert memory allocation\n");
> + goto out_unlock;
> + case -EBUSY:
> + pr_err("xa insert entry already present\n");
> + goto out_unlock;
> + default:
> + goto out_unlock;
> }
> }
> +
I don't think we need the switch statement, just return any error
encountered.
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next prev parent reply other threads:[~2020-07-01 6:08 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-01 2:25 [PATCH V2 0/2] nvme: replace linked list with xarray for ns tracking Chaitanya Kulkarni
2020-07-01 2:25 ` [PATCH V2 1/2] nvme-core: use xarray for ctrl " Chaitanya Kulkarni
2020-07-01 13:12 ` Christoph Hellwig
2020-07-01 16:44 ` Keith Busch
2020-07-01 18:19 ` Chaitanya Kulkarni
2020-07-01 18:29 ` Keith Busch
2020-07-01 18:40 ` Chaitanya Kulkarni
2020-07-01 2:25 ` [PATCH V2 2/2] nvmet: use xarray for ctrl ns storing Chaitanya Kulkarni
2020-07-01 6:08 ` Christoph Hellwig [this message]
2020-07-01 18:36 ` Chaitanya Kulkarni
2020-07-01 5:36 ` [PATCH V2 0/2] nvme: replace linked list with xarray for ns tracking Christoph Hellwig
2020-07-01 13:21 ` Keith Busch
2020-07-01 16:49 ` Sagi Grimberg
2020-07-01 18:43 ` Chaitanya Kulkarni
2020-07-01 18:41 ` Chaitanya Kulkarni
2020-07-01 18:41 ` Chaitanya Kulkarni
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