2020-09-25 20:36:14

by Dan Williams

[permalink] [raw]
Subject: [PATCH v5 03/17] device-dax/kmem: move resource name tracking to drvdata

Towards removing the mode specific @dax_kmem_res attribute from the
generic 'struct dev_dax', and preparing for multi-range support, move
resource name tracking to driver data. The memory for the resource name
needs to have its own lifetime separate from the device bind lifetime
for cases where the driver is unbound, but the kmem range could not be
unplugged from the page allocator.

Cc: David Hildenbrand <[email protected]>
Cc: Vishal Verma <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Pavel Tatashin <[email protected]>
Cc: Brice Goglin <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Ira Weiny <[email protected]>
Cc: Jia He <[email protected]>
Cc: Joao Martins <[email protected]>
Cc: Jonathan Cameron <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
---
drivers/dax/kmem.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index b0d6a99cf12d..6fe2cb1c5f7c 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -34,7 +34,7 @@ int dev_dax_kmem_probe(struct device *dev)
struct dev_dax *dev_dax = to_dev_dax(dev);
struct range range = dax_kmem_range(dev_dax);
struct resource *new_res;
- const char *new_res_name;
+ char *res_name;
int numa_node;
int rc;

@@ -51,15 +51,15 @@ int dev_dax_kmem_probe(struct device *dev)
return -EINVAL;
}

- new_res_name = kstrdup(dev_name(dev), GFP_KERNEL);
- if (!new_res_name)
+ res_name = kstrdup(dev_name(dev), GFP_KERNEL);
+ if (!res_name)
return -ENOMEM;

/* Region is permanently reserved if hotremove fails. */
- new_res = request_mem_region(range.start, range_len(&range), new_res_name);
+ new_res = request_mem_region(range.start, range_len(&range), res_name);
if (!new_res) {
dev_warn(dev, "could not reserve region [%#llx-%#llx]\n", range.start, range.end);
- kfree(new_res_name);
+ kfree(res_name);
return -EBUSY;
}

@@ -80,9 +80,11 @@ int dev_dax_kmem_probe(struct device *dev)
if (rc) {
release_resource(new_res);
kfree(new_res);
- kfree(new_res_name);
+ kfree(res_name);
return rc;
}
+
+ dev_set_drvdata(dev, res_name);
dev_dax->dax_kmem_res = new_res;

return 0;
@@ -94,7 +96,7 @@ static int dev_dax_kmem_remove(struct device *dev)
struct dev_dax *dev_dax = to_dev_dax(dev);
struct range range = dax_kmem_range(dev_dax);
struct resource *res = dev_dax->dax_kmem_res;
- const char *res_name = res->name;
+ const char *res_name = dev_get_drvdata(dev);
int rc;

/*


2020-09-30 16:21:27

by David Hildenbrand

[permalink] [raw]
Subject: Re: [PATCH v5 03/17] device-dax/kmem: move resource name tracking to drvdata

On 25.09.20 21:11, Dan Williams wrote:
> Towards removing the mode specific @dax_kmem_res attribute from the
> generic 'struct dev_dax', and preparing for multi-range support, move
> resource name tracking to driver data. The memory for the resource name
> needs to have its own lifetime separate from the device bind lifetime
> for cases where the driver is unbound, but the kmem range could not be
> unplugged from the page allocator.
>
> Cc: David Hildenbrand <[email protected]>
> Cc: Vishal Verma <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: Pavel Tatashin <[email protected]>
> Cc: Brice Goglin <[email protected]>
> Cc: Dave Jiang <[email protected]>
> Cc: David Hildenbrand <[email protected]>
> Cc: Ira Weiny <[email protected]>
> Cc: Jia He <[email protected]>
> Cc: Joao Martins <[email protected]>
> Cc: Jonathan Cameron <[email protected]>
> Signed-off-by: Dan Williams <[email protected]>
> ---
> drivers/dax/kmem.c | 16 +++++++++-------
> 1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
> index b0d6a99cf12d..6fe2cb1c5f7c 100644
> --- a/drivers/dax/kmem.c
> +++ b/drivers/dax/kmem.c
> @@ -34,7 +34,7 @@ int dev_dax_kmem_probe(struct device *dev)
> struct dev_dax *dev_dax = to_dev_dax(dev);
> struct range range = dax_kmem_range(dev_dax);
> struct resource *new_res;
> - const char *new_res_name;
> + char *res_name;

I wonder why that change ...

> int numa_node;
> int rc;
>
> @@ -51,15 +51,15 @@ int dev_dax_kmem_probe(struct device *dev)
> return -EINVAL;
> }
>
> - new_res_name = kstrdup(dev_name(dev), GFP_KERNEL);
> - if (!new_res_name)
> + res_name = kstrdup(dev_name(dev), GFP_KERNEL);
> + if (!res_name)
> return -ENOMEM;
>
> /* Region is permanently reserved if hotremove fails. */
> - new_res = request_mem_region(range.start, range_len(&range), new_res_name);
> + new_res = request_mem_region(range.start, range_len(&range), res_name);
> if (!new_res) {
> dev_warn(dev, "could not reserve region [%#llx-%#llx]\n", range.start, range.end);
> - kfree(new_res_name);
> + kfree(res_name);
> return -EBUSY;
> }
>
> @@ -80,9 +80,11 @@ int dev_dax_kmem_probe(struct device *dev)
> if (rc) {
> release_resource(new_res);
> kfree(new_res);
> - kfree(new_res_name);
> + kfree(res_name);
> return rc;
> }
> +
> + dev_set_drvdata(dev, res_name);
> dev_dax->dax_kmem_res = new_res;
>
> return 0;
> @@ -94,7 +96,7 @@ static int dev_dax_kmem_remove(struct device *dev)
> struct dev_dax *dev_dax = to_dev_dax(dev);
> struct range range = dax_kmem_range(dev_dax);
> struct resource *res = dev_dax->dax_kmem_res;
> - const char *res_name = res->name;
> + const char *res_name = dev_get_drvdata(dev);

... because here you're back to "const".

> int rc;
>
> /*
>

I do wonder if it wouldn't all be easier to just have some

struct {
const char *res_name;
struct resource *res;
};

allocating that and storing it as drvdata. But let's see what the next
patch brings :)

--
Thanks,

David / dhildenb