[PATCHv2] NVMe: Fix removal in case of active namespace list scanning method

[PATCHv2] NVMe: Fix removal in case of active namespace list scanning method

[Sunad Bhandary S]

From: Sunad Bhandary <sunad.s@samsung.com>

In case of the active namespace list scanning method, a namespace that
is detached is not removed from the host if it was the last entry in
the list. Fix this by adding a scan to validate namespaces greater than
the value of prev.

This also handles the case of removing namespaces whose value exceed
the device's reported number of namespaces.

Signed-off-by: Sunad Bhandary S <sunad.s at samsung.com>
Reviewed-by: Christoph Hellwig <hch at lst.de>
---
v1 -> v2:
 Removed unnecessary braces around if condition
 
 drivers/nvme/host/core.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 2de248b..3da998f 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1483,6 +1483,17 @@ static void nvme_validate_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 		nvme_alloc_ns(ctrl, nsid);
 }
 
+static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
+					unsigned nsid)
+{
+	struct nvme_ns *ns, *next;
+
+	list_for_each_entry_safe(ns, next, &ctrl->namespaces, list) {
+		if (ns->ns_id > nsid)
+			nvme_ns_remove(ns);
+	}
+}
+
 static int nvme_scan_ns_list(struct nvme_ctrl *ctrl, unsigned nn)
 {
 	struct nvme_ns *ns;
@@ -1497,7 +1508,7 @@ static int nvme_scan_ns_list(struct nvme_ctrl *ctrl, unsigned nn)
 	for (i = 0; i < num_lists; i++) {
 		ret = nvme_identify_ns_list(ctrl, prev, ns_list);
 		if (ret)
-			goto out;
+			goto free;
 
 		for (j = 0; j < min(nn, 1024U); j++) {
 			nsid = le32_to_cpu(ns_list[j]);
@@ -1515,13 +1526,14 @@ static int nvme_scan_ns_list(struct nvme_ctrl *ctrl, unsigned nn)
 		nn -= j;
 	}
  out:
+	nvme_remove_invalid_namespaces(ctrl, prev);
+ free:
 	kfree(ns_list);
 	return ret;
 }
 
 static void nvme_scan_ns_sequential(struct nvme_ctrl *ctrl, unsigned nn)
 {
-	struct nvme_ns *ns, *next;
 	unsigned i;
 
 	lockdep_assert_held(&ctrl->namespaces_mutex);
@@ -1529,10 +1541,7 @@ static void nvme_scan_ns_sequential(struct nvme_ctrl *ctrl, unsigned nn)
 	for (i = 1; i <= nn; i++)
 		nvme_validate_ns(ctrl, i);
 
-	list_for_each_entry_safe(ns, next, &ctrl->namespaces, list) {
-		if (ns->ns_id > nn)
-			nvme_ns_remove(ns);
-	}
+	nvme_remove_invalid_namespaces(ctrl, nn);
 }
 
 static void nvme_scan_work(struct work_struct *work)
-- 
1.9.3

[PATCHv2] NVMe: Fix removal in case of active namespace list scanning method

[Keith Busch]

On Fri, May 27, 2016@03:59:43PM +0530, Sunad Bhandary S wrote:
>  static int nvme_scan_ns_list(struct nvme_ctrl *ctrl, unsigned nn)
>  {
>  	struct nvme_ns *ns;
> @@ -1497,7 +1508,7 @@ static int nvme_scan_ns_list(struct nvme_ctrl *ctrl, unsigned nn)
>  	for (i = 0; i < num_lists; i++) {
>  		ret = nvme_identify_ns_list(ctrl, prev, ns_list);
>  		if (ret)
> -			goto out;
> +			goto free;
>  
>  		for (j = 0; j < min(nn, 1024U); j++) {
>  			nsid = le32_to_cpu(ns_list[j]);
> @@ -1515,13 +1526,14 @@ static int nvme_scan_ns_list(struct nvme_ctrl *ctrl, unsigned nn)
>  		nn -= j;
>  	}
>   out:
> +	nvme_remove_invalid_namespaces(ctrl, prev);
> + free:

We don't want to remove the namespaces on error here. That could remove
valid, in use namespaces: if nvme_identify_ns_list fails (maybe controller
just doesn't support that identify mode), we do the sequential scanning.

Just leave the 'goto free' alone, and call nvme_remove_invalid_namespaces
only on success.

[PATCHv2] NVMe: Fix removal in case of active namespace list scanning method

[Sunad Bhandary]

>We don't want to remove the namespaces on error here. That could
>remove valid, in use namespaces: if nvme_identify_ns_list fails (maybe
>controller just doesn't support that identify mode), we do the
>sequential scanning.

>Just leave the 'goto free' alone, and call
>nvme_remove_invalid_namespaces only on success.

In the patch, the namespaces are not removed on failure of identify
list. If nvme_identify_ns_list fails, the value is returned and
sequential scanning is done. The call to nvme_remove_invalid_namespaces 
is done when the value of nsid in the list is 0.

Snapshot of patch:
  ....
	ret = nvme_identify_ns_list(ctrl, prev, ns_list);
                 if (ret)
                         goto free;
  ....
  	nsid = le32_to_cpu(ns_list[j]);
                         if (!nsid)
                                 goto out;
  ....

  out:
         nvme_remove_invalid_namespaces(ctrl, prev);
  free:
         kfree(ns_list);
         return ret;

This should be able to handle error scenarios or am I missing something?

Thanks and Regards,
Sunad

[PATCHv2] NVMe: Fix removal in case of active namespace list scanning method

[Keith Busch]

On Mon, May 30, 2016@04:15:41PM +0530, Sunad Bhandary wrote:
> In the patch, the namespaces are not removed on failure of identify
> list. If nvme_identify_ns_list fails, the value is returned and
> sequential scanning is done. The call to nvme_remove_invalid_namespaces is
> done when the value of nsid in the list is 0.

Sorry, my mistake. You're right, it is good as-is.

[PATCHv2] NVMe: Fix removal in case of active namespace list scanning method

[Sunad Bhandary]

Hi Jens,

Can this be picked up?

Thanks and Regards,
Sunad

> -----Original Message-----
> From: Linux-nvme [mailto:linux-nvme-bounces at lists.infradead.org] On Behalf Of Keith Busch
> Sent: Tuesday, May 31, 2016 8:05 PM
> To: Sunad Bhandary
> Cc: hch at infradead.org; linux-nvme at lists.infradead.org
> Subject: Re: Re: [PATCHv2] NVMe: Fix removal in case of active namespace list scanning method
>
> On Mon, May 30, 2016@04:15:41PM +0530, Sunad Bhandary wrote:
>> In the patch, the namespaces are not removed on failure of identify
>> list. If nvme_identify_ns_list fails, the value is returned and
>> sequential scanning is done. The call to
>> nvme_remove_invalid_namespaces is done when the value of nsid in the list is 0.
>
> Sorry, my mistake. You're right, it is good as-is.