Introduce a guard(device) macro to lock a 'struct device', and unlock it
automatically when going out of scope using Scope Based Resource
Management semantics. A lot of the sysfs attribute writes in
drivers/dax/bus.c benefit from a cleanup using these, so change these
where applicable.
Cc: Joao Martins <[email protected]>
Suggested-by: Dan Williams <[email protected]>
Signed-off-by: Vishal Verma <[email protected]>
---
include/linux/device.h | 2 +
drivers/dax/bus.c | 109 +++++++++++++++++++------------------------------
2 files changed, 44 insertions(+), 67 deletions(-)
diff --git a/include/linux/device.h b/include/linux/device.h
index d7a72a8749ea..a83efd9ae949 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -1131,6 +1131,8 @@ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
void device_set_of_node_from_dev(struct device *dev, const struct device *dev2);
void device_set_node(struct device *dev, struct fwnode_handle *fwnode);
+DEFINE_GUARD(device, struct device *, device_lock(_T), device_unlock(_T))
+
static inline int dev_num_vf(struct device *dev)
{
if (dev->bus && dev->bus->num_vf)
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 1ff1ab5fa105..ce1356ac6dc2 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -296,9 +296,8 @@ static ssize_t available_size_show(struct device *dev,
struct dax_region *dax_region = dev_get_drvdata(dev);
unsigned long long size;
- device_lock(dev);
+ guard(device)(dev);
size = dax_region_avail_size(dax_region);
- device_unlock(dev);
return sprintf(buf, "%llu\n", size);
}
@@ -314,10 +313,9 @@ static ssize_t seed_show(struct device *dev,
if (is_static(dax_region))
return -EINVAL;
- device_lock(dev);
+ guard(device)(dev);
seed = dax_region->seed;
rc = sprintf(buf, "%s\n", seed ? dev_name(seed) : "");
- device_unlock(dev);
return rc;
}
@@ -333,10 +331,9 @@ static ssize_t create_show(struct device *dev,
if (is_static(dax_region))
return -EINVAL;
- device_lock(dev);
+ guard(device)(dev);
youngest = dax_region->youngest;
rc = sprintf(buf, "%s\n", youngest ? dev_name(youngest) : "");
- device_unlock(dev);
return rc;
}
@@ -345,7 +342,14 @@ static ssize_t create_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len)
{
struct dax_region *dax_region = dev_get_drvdata(dev);
+ struct dev_dax_data data = {
+ .dax_region = dax_region,
+ .size = 0,
+ .id = -1,
+ .memmap_on_memory = false,
+ };
unsigned long long avail;
+ struct dev_dax *dev_dax;
ssize_t rc;
int val;
@@ -358,38 +362,26 @@ static ssize_t create_store(struct device *dev, struct device_attribute *attr,
if (val != 1)
return -EINVAL;
- device_lock(dev);
+ guard(device)(dev);
avail = dax_region_avail_size(dax_region);
if (avail == 0)
- rc = -ENOSPC;
- else {
- struct dev_dax_data data = {
- .dax_region = dax_region,
- .size = 0,
- .id = -1,
- .memmap_on_memory = false,
- };
- struct dev_dax *dev_dax = devm_create_dev_dax(&data);
+ return -ENOSPC;
- if (IS_ERR(dev_dax))
- rc = PTR_ERR(dev_dax);
- else {
- /*
- * In support of crafting multiple new devices
- * simultaneously multiple seeds can be created,
- * but only the first one that has not been
- * successfully bound is tracked as the region
- * seed.
- */
- if (!dax_region->seed)
- dax_region->seed = &dev_dax->dev;
- dax_region->youngest = &dev_dax->dev;
- rc = len;
- }
- }
- device_unlock(dev);
+ dev_dax = devm_create_dev_dax(&data);
+ if (IS_ERR(dev_dax))
+ return PTR_ERR(dev_dax);
- return rc;
+ /*
+ * In support of crafting multiple new devices
+ * simultaneously multiple seeds can be created,
+ * but only the first one that has not been
+ * successfully bound is tracked as the region
+ * seed.
+ */
+ if (!dax_region->seed)
+ dax_region->seed = &dev_dax->dev;
+ dax_region->youngest = &dev_dax->dev;
+ return len;
}
static DEVICE_ATTR_RW(create);
@@ -481,12 +473,9 @@ static int __free_dev_dax_id(struct dev_dax *dev_dax)
static int free_dev_dax_id(struct dev_dax *dev_dax)
{
struct device *dev = &dev_dax->dev;
- int rc;
- device_lock(dev);
- rc = __free_dev_dax_id(dev_dax);
- device_unlock(dev);
- return rc;
+ guard(device)(dev);
+ return __free_dev_dax_id(dev_dax);
}
static int alloc_dev_dax_id(struct dev_dax *dev_dax)
@@ -908,9 +897,8 @@ static ssize_t size_show(struct device *dev,
struct dev_dax *dev_dax = to_dev_dax(dev);
unsigned long long size;
- device_lock(dev);
+ guard(device)(dev);
size = dev_dax_size(dev_dax);
- device_unlock(dev);
return sprintf(buf, "%llu\n", size);
}
@@ -1080,15 +1068,12 @@ static ssize_t size_store(struct device *dev, struct device_attribute *attr,
return -EINVAL;
}
- device_lock(dax_region->dev);
- if (!dax_region->dev->driver) {
- device_unlock(dax_region->dev);
+ guard(device)(dax_region->dev);
+ if (!dax_region->dev->driver)
return -ENXIO;
- }
- device_lock(dev);
+
+ guard(device)(dev);
rc = dev_dax_resize(dax_region, dev_dax, val);
- device_unlock(dev);
- device_unlock(dax_region->dev);
return rc == 0 ? len : rc;
}
@@ -1138,18 +1123,14 @@ static ssize_t mapping_store(struct device *dev, struct device_attribute *attr,
return rc;
rc = -ENXIO;
- device_lock(dax_region->dev);
- if (!dax_region->dev->driver) {
- device_unlock(dax_region->dev);
+ guard(device)(dax_region->dev);
+ if (!dax_region->dev->driver)
return rc;
- }
- device_lock(dev);
+ guard(device)(dev);
to_alloc = range_len(&r);
if (alloc_is_aligned(dev_dax, to_alloc))
rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc);
- device_unlock(dev);
- device_unlock(dax_region->dev);
return rc == 0 ? len : rc;
}
@@ -1196,26 +1177,20 @@ static ssize_t align_store(struct device *dev, struct device_attribute *attr,
if (!dax_align_valid(val))
return -EINVAL;
- device_lock(dax_region->dev);
- if (!dax_region->dev->driver) {
- device_unlock(dax_region->dev);
+ guard(device)(dax_region->dev);
+ if (!dax_region->dev->driver)
return -ENXIO;
- }
- device_lock(dev);
- if (dev->driver) {
- rc = -EBUSY;
- goto out_unlock;
- }
+ guard(device)(dev);
+ if (dev->driver)
+ return -EBUSY;
align_save = dev_dax->align;
dev_dax->align = val;
rc = dev_dax_validate_align(dev_dax);
if (rc)
dev_dax->align = align_save;
-out_unlock:
- device_unlock(dev);
- device_unlock(dax_region->dev);
+
return rc == 0 ? len : rc;
}
static DEVICE_ATTR_RW(align);
--
2.41.0
Vishal Verma wrote:
> Introduce a guard(device) macro to lock a 'struct device', and unlock it
> automatically when going out of scope using Scope Based Resource
> Management semantics. A lot of the sysfs attribute writes in
> drivers/dax/bus.c benefit from a cleanup using these, so change these
> where applicable.
>
> Cc: Joao Martins <[email protected]>
> Suggested-by: Dan Williams <[email protected]>
> Signed-off-by: Vishal Verma <[email protected]>
>
Reviewed-by: Ira Weiny <[email protected]>
On Tue, 12 Dec 2023 12:08:31 -0700
Vishal Verma <[email protected]> wrote:
> Introduce a guard(device) macro to lock a 'struct device', and unlock it
> automatically when going out of scope using Scope Based Resource
> Management semantics. A lot of the sysfs attribute writes in
> drivers/dax/bus.c benefit from a cleanup using these, so change these
> where applicable.
>
> Cc: Joao Martins <[email protected]>
> Suggested-by: Dan Williams <[email protected]>
> Signed-off-by: Vishal Verma <[email protected]>
Hi Vishal,
I'm a big fan of this cleanup.h stuff so very happen to see this getting used here.
There are added opportunities for cleanup that result.
Note that almost every time I see people using this stuff they don't look again
at the code post the change so miss the wider cleanup that it enables. So you are
in good company ;)
Jonathan
> ---
> include/linux/device.h | 2 +
> drivers/dax/bus.c | 109 +++++++++++++++++++------------------------------
> 2 files changed, 44 insertions(+), 67 deletions(-)
>
> diff --git a/include/linux/device.h b/include/linux/device.h
> index d7a72a8749ea..a83efd9ae949 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -1131,6 +1131,8 @@ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
> void device_set_of_node_from_dev(struct device *dev, const struct device *dev2);
> void device_set_node(struct device *dev, struct fwnode_handle *fwnode);
>
> +DEFINE_GUARD(device, struct device *, device_lock(_T), device_unlock(_T))
Nice. I'd expect this to be widely adopted, so maybe to make things less painful
for backporting changes that depend on it, make this a separate trivial patch
rather than having this in here.
> +
> static inline int dev_num_vf(struct device *dev)
> {
> if (dev->bus && dev->bus->num_vf)
> diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
> index 1ff1ab5fa105..ce1356ac6dc2 100644
> --- a/drivers/dax/bus.c
> +++ b/drivers/dax/bus.c
> @@ -296,9 +296,8 @@ static ssize_t available_size_show(struct device *dev,
> struct dax_region *dax_region = dev_get_drvdata(dev);
> unsigned long long size;
>
> - device_lock(dev);
> + guard(device)(dev);
> size = dax_region_avail_size(dax_region);
> - device_unlock(dev);
>
> return sprintf(buf, "%llu\n", size);
return sprintf(buf, @%llu\n@, dax_region_avail_size(dax_region));
and drop the local variable that adds little perhaps?
> }
> @@ -314,10 +313,9 @@ static ssize_t seed_show(struct device *dev,
> if (is_static(dax_region))
> return -EINVAL;
>
> - device_lock(dev);
> + guard(device)(dev);
> seed = dax_region->seed;
> rc = sprintf(buf, "%s\n", seed ? dev_name(seed) : "");
return sprintf();
> - device_unlock(dev);
>
> return rc;
> }
> @@ -333,10 +331,9 @@ static ssize_t create_show(struct device *dev,
> if (is_static(dax_region))
> return -EINVAL;
>
> - device_lock(dev);
> + guard(device)(dev);
> youngest = dax_region->youngest;
> rc = sprintf(buf, "%s\n", youngest ? dev_name(youngest) : "");
return sprintf();
> - device_unlock(dev);
>
> return rc;
> }
> @@ -345,7 +342,14 @@ static ssize_t create_store(struct device *dev, struct device_attribute *attr,
> const char *buf, size_t len)
> {
> struct dax_region *dax_region = dev_get_drvdata(dev);
> + struct dev_dax_data data = {
> + .dax_region = dax_region,
> + .size = 0,
> + .id = -1,
> + .memmap_on_memory = false,
> + };
> unsigned long long avail;
> + struct dev_dax *dev_dax;
> ssize_t rc;
> int val;
>
> @@ -358,38 +362,26 @@ static ssize_t create_store(struct device *dev, struct device_attribute *attr,
> if (val != 1)
> return -EINVAL;
>
> - device_lock(dev);
> + guard(device)(dev);
> avail = dax_region_avail_size(dax_region);
> if (avail == 0)
> - rc = -ENOSPC;
> - else {
> - struct dev_dax_data data = {
> - .dax_region = dax_region,
> - .size = 0,
> - .id = -1,
> - .memmap_on_memory = false,
> - };
> - struct dev_dax *dev_dax = devm_create_dev_dax(&data);
> + return -ENOSPC;
>
> - if (IS_ERR(dev_dax))
> - rc = PTR_ERR(dev_dax);
> - else {
> - /*
> - * In support of crafting multiple new devices
> - * simultaneously multiple seeds can be created,
> - * but only the first one that has not been
> - * successfully bound is tracked as the region
> - * seed.
> - */
> - if (!dax_region->seed)
> - dax_region->seed = &dev_dax->dev;
> - dax_region->youngest = &dev_dax->dev;
> - rc = len;
> - }
> - }
> - device_unlock(dev);
> + dev_dax = devm_create_dev_dax(&data);
> + if (IS_ERR(dev_dax))
> + return PTR_ERR(dev_dax);
>
> - return rc;
> + /*
> + * In support of crafting multiple new devices
rewrap this comment for the new indent.
> + * simultaneously multiple seeds can be created,
> + * but only the first one that has not been
> + * successfully bound is tracked as the region
> + * seed.
> + */
> + if (!dax_region->seed)
> + dax_region->seed = &dev_dax->dev;
> + dax_region->youngest = &dev_dax->dev;
Trivial but blank line here would be a nice to have
> + return len;
> }
...
> @@ -1138,18 +1123,14 @@ static ssize_t mapping_store(struct device *dev, struct device_attribute *attr,
> return rc;
>
> rc = -ENXIO;
Not needed with suggested changes that follow.
> - device_lock(dax_region->dev);
> - if (!dax_region->dev->driver) {
> - device_unlock(dax_region->dev);
> + guard(device)(dax_region->dev);
> + if (!dax_region->dev->driver)
> return rc;
return -ENXIO;
> - }
> - device_lock(dev);
>
> + guard(device)(dev);
> to_alloc = range_len(&r);
> if (alloc_is_aligned(dev_dax, to_alloc))
> rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc);
Flip logic here and I'd drop the ternary stuff as well - same in other
similar cases in this patch (though that is just personal taste)
if (!alloc_is_aligned(dev_dax, to_allco))
return -ENXIO.
rc = alloc_dev_dax_range(dev_dax, r.start, to_allco)
if (rc)
return rc;
return len;
> - device_unlock(dev);
> - device_unlock(dax_region->dev);
>
> return rc == 0 ? len : rc;
> }
>