[PATCH 0/2] A few code cleanups

[PATCH 0/2] A few code cleanups

[Edmund Nadolski]

This patchset adds a few simple cleanups to the nvme code.

Edmund Nadolski (2):
  nvme: remove unused return code from nvme_alloc_ns
  nvme: else following return is not needed

 drivers/nvme/host/core.c | 21 ++++++---------------
 drivers/nvme/host/pci.c  |  2 +-
 2 files changed, 7 insertions(+), 16 deletions(-)

-- 
2.20.1


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[PATCH 1/2] nvme: remove unused return code from nvme_alloc_ns

[Edmund Nadolski]

The return code of nvme_alloc_ns is never used, so change it
to void.

Signed-off-by: Edmund Nadolski <edmund.nadolski@intel.com>
---
 drivers/nvme/host/core.c | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 9696404a6182..c22d986d053a 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3446,7 +3446,7 @@ static int nvme_setup_streams_ns(struct nvme_ctrl *ctrl, struct nvme_ns *ns)
 	return 0;
 }
 
-static int nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
+static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 {
 	struct nvme_ns *ns;
 	struct gendisk *disk;
@@ -3456,13 +3456,11 @@ static int nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 
 	ns = kzalloc_node(sizeof(*ns), GFP_KERNEL, node);
 	if (!ns)
-		return -ENOMEM;
+		return;
 
 	ns->queue = blk_mq_init_queue(ctrl->tagset);
-	if (IS_ERR(ns->queue)) {
-		ret = PTR_ERR(ns->queue);
+	if (IS_ERR(ns->queue))
 		goto out_free_ns;
-	}
 
 	if (ctrl->opts && ctrl->opts->data_digest)
 		ns->queue->backing_dev_info->capabilities
@@ -3485,10 +3483,8 @@ static int nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	if (ret)
 		goto out_free_queue;
 
-	if (id->ncap == 0) {
-		ret = -EINVAL;
+	if (id->ncap == 0)
 		goto out_free_id;
-	}
 
 	ret = nvme_init_ns_head(ns, nsid, id);
 	if (ret)
@@ -3497,10 +3493,8 @@ static int nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	nvme_set_disk_name(disk_name, ns, ctrl, &flags);
 
 	disk = alloc_disk_node(0, node);
-	if (!disk) {
-		ret = -ENOMEM;
+	if (!disk)
 		goto out_unlink_ns;
-	}
 
 	disk->fops = &nvme_fops;
 	disk->private_data = ns;
@@ -3531,7 +3525,7 @@ static int nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	nvme_fault_inject_init(&ns->fault_inject, ns->disk->disk_name);
 	kfree(id);
 
-	return 0;
+	return;
  out_put_disk:
 	put_disk(ns->disk);
  out_unlink_ns:
@@ -3545,9 +3539,6 @@ static int nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	blk_cleanup_queue(ns->queue);
  out_free_ns:
 	kfree(ns);
-	if (ret > 0)
-		ret = blk_status_to_errno(nvme_error_status(ret));
-	return ret;
 }
 
 static void nvme_ns_remove(struct nvme_ns *ns)
-- 
2.20.1


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[PATCH 2/2] nvme: else following return is not needed

[Edmund Nadolski]

Remove unnecessary keyword in nvme_create_queue().

Signed-off-by: Edmund Nadolski <edmund.nadolski@intel.com>
---
 drivers/nvme/host/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index c40a672e5047..76aa4bef27b8 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1548,7 +1548,7 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, int qid, bool polled)
 	result = adapter_alloc_sq(dev, qid, nvmeq);
 	if (result < 0)
 		return result;
-	else if (result)
+	if (result)
 		goto release_cq;
 
 	nvmeq->cq_vector = vector;
-- 
2.20.1


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Re: [PATCH 1/2] nvme: remove unused return code from nvme_alloc_ns

[Johannes Thumshirn]

On 25/11/2019 17:06, Edmund Nadolski wrote:
> The return code of nvme_alloc_ns is never used, so change it
> to void.

Oh no, please do it the other way round, check the return value of
nvme_alloc_ns() and handle error properly.

nvme_alloc_ns() is doing memory allocations and these can fail (although
less likely because of the GFP_KERNEL allocations).

-- 
Johannes Thumshirn                            SUSE Labs Filesystems
jthumshirn@suse.de                                +49 911 74053 689
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5
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(HRB 36809, AG Nürnberg)
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Re: [PATCH 1/2] nvme: remove unused return code from nvme_alloc_ns

[Nadolski, Edmund]

On 11/25/2019 9:09 AM, Johannes Thumshirn wrote:
> On 25/11/2019 17:06, Edmund Nadolski wrote:
>> The return code of nvme_alloc_ns is never used, so change it
>> to void.
> 
> Oh no, please do it the other way round, check the return value of
> nvme_alloc_ns() and handle error properly.
> 
> nvme_alloc_ns() is doing memory allocations and these can fail (although
> less likely because of the GFP_KERNEL allocations).

I considered that, tho it looked to me like the caller (nvme_validate_ns) and 
its callers (nvme_scan_ns_list, nvme_scan_ns_sequential) don't really care, 
and intend simply to continue on regardless of memory alloc failure(s).

I can either add the -ENOMEM handling, or clarify the caller's intent w/some 
comments. Which is the way to go?

Thanks,
Ed


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Re: [PATCH 1/2] nvme: remove unused return code from nvme_alloc_ns

[Keith Busch]

On Mon, Nov 25, 2019 at 09:46:08AM -0700, Nadolski, Edmund wrote:
> On 11/25/2019 9:09 AM, Johannes Thumshirn wrote:
> > On 25/11/2019 17:06, Edmund Nadolski wrote:
> > > The return code of nvme_alloc_ns is never used, so change it
> > > to void.
> > 
> > Oh no, please do it the other way round, check the return value of
> > nvme_alloc_ns() and handle error properly.
> > 
> > nvme_alloc_ns() is doing memory allocations and these can fail (although
> > less likely because of the GFP_KERNEL allocations).
> 
> I considered that, tho it looked to me like the caller (nvme_validate_ns)
> and its callers (nvme_scan_ns_list, nvme_scan_ns_sequential) don't really
> care, and intend simply to continue on regardless of memory alloc
> failure(s).
> 
> I can either add the -ENOMEM handling, or clarify the caller's intent w/some
> comments. Which is the way to go?

It would be informative to just log the error that occurred so we have
something indicating why an expected namespace wasn't created. Otherwise,
I can't think of anything else the caller should do in response to an
error in this path.

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Re: [PATCH 1/2] nvme: remove unused return code from nvme_alloc_ns

[Chaitanya Kulkarni]

On 11/25/2019 09:07 AM, Keith Busch wrote:
> It would be informative to just log the error that occurred so we have
> something indicating why an expected namespace wasn't created. Otherwise,
> I can't think of anything else the caller should do in response to an
> error in this path.

Please do this, shouldn't be ignoring return value completely at first
place.


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Re: [PATCH 1/2] nvme: remove unused return code from nvme_alloc_ns

[Christoph Hellwig]

On Tue, Nov 26, 2019 at 04:01:11AM +0000, Chaitanya Kulkarni wrote:
> On 11/25/2019 09:07 AM, Keith Busch wrote:
> > It would be informative to just log the error that occurred so we have
> > something indicating why an expected namespace wasn't created. Otherwise,
> > I can't think of anything else the caller should do in response to an
> > error in this path.
> 
> Please do this, shouldn't be ignoring return value completely at first
> place.

Well, what would you do instead?  We call nvme_alloc_ns during the
initial probe and every reset / recan.  If we fail to allocate a
controller for whatever reason we'd much rather still have a working
controller with at least the admin queue and maybe other namespaces
rather than shutting everything down.  So just logging a message
inside nvme_alloc_ns as suggested by Keith sounds like a good idea to
me.

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Re: [PATCH 2/2] nvme: else following return is not needed

[Christoph Hellwig]

On Mon, Nov 25, 2019 at 09:06:12AM -0700, Edmund Nadolski wrote:
> Remove unnecessary keyword in nvme_create_queue().
> 
> Signed-off-by: Edmund Nadolski <edmund.nadolski@intel.com>

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

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Re: [PATCH 2/2] nvme: else following return is not needed

[Keith Busch]

Applied to nvme/for-5.5

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