diff mbox series

[7/9] dax: stub out dax_supported for !CONFIG_FS_DAX

Message ID 20210823123516.969486-8-hch@lst.de (mailing list archive)
State Superseded
Headers show
Series [1/9] fsdax: improve the FS_DAX Kconfig description and help text | expand

Commit Message

Christoph Hellwig Aug. 23, 2021, 12:35 p.m. UTC 
dax_supported calls into ->dax_supported which checks for fsdax support.
Don't bother building it for !CONFIG_FS_DAX as it will always return
false.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/dax/super.c | 36 ++++++++++++++++++------------------
 include/linux/dax.h | 18 ++++++++++--------
 2 files changed, 28 insertions(+), 26 deletions(-)

Comments

Dan Williams Aug. 23, 2021, 9:15 p.m. UTC | #1 
On Mon, Aug 23, 2021 at 5:43 AM Christoph Hellwig <hch@lst.de> wrote:
>
> dax_supported calls into ->dax_supported which checks for fsdax support.
> Don't bother building it for !CONFIG_FS_DAX as it will always return
> false.
>

Looks good, modulo formatting question below:

Reviewed-by: Dan Williams <dan.j.williams@intel.com>

> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index 0a3ef9701e03..32dce5763f2c 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
[..]
> @@ -149,6 +144,13 @@ static inline bool bdev_dax_supported(struct block_device *bdev,
>
>  #define generic_fsdax_supported                NULL
>
> +static inline bool dax_supported(struct dax_device *dax_dev,
> +               struct block_device *bdev, int blocksize, sector_t start,
> +               sector_t len)
> +{
> +       return false;
> +}

I've started clang-formatting new dax and nvdimm code:

static inline bool dax_supported(struct dax_device *dax_dev,
                                 struct block_device *bdev, int blocksize,
                                 sector_t start, sector_t len)
{
        return false;
}

...but I also don't mind staying consistent with the surrounding code for now.
Christoph Hellwig Aug. 24, 2021, 5:44 a.m. UTC | #2 
On Mon, Aug 23, 2021 at 02:15:47PM -0700, Dan Williams wrote:
> > +static inline bool dax_supported(struct dax_device *dax_dev,
> > +               struct block_device *bdev, int blocksize, sector_t start,
> > +               sector_t len)
> > +{
> > +       return false;
> > +}
> 
> I've started clang-formatting new dax and nvdimm code:
> 
> static inline bool dax_supported(struct dax_device *dax_dev,
>                                  struct block_device *bdev, int blocksize,
>                                  sector_t start, sector_t len)
> {
>         return false;
> }
> 
> ...but I also don't mind staying consistent with the surrounding code for now.

While Linux has historically used both styles, I find this second one
pretty horrible.  It is hard to read due to the huge amounts of wasted
space, and needs constant realignment when the return type or symbol
name changes.
diff mbox series

Patch

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 8e8ccb3e956b..eed02729add3 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -201,6 +201,24 @@  bool generic_fsdax_supported(struct dax_device *dax_dev,
 	return true;
 }
 EXPORT_SYMBOL_GPL(generic_fsdax_supported);
+
+bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
+		int blocksize, sector_t start, sector_t len)
+{
+	bool ret = false;
+	int id;
+
+	if (!dax_dev)
+		return false;
+
+	id = dax_read_lock();
+	if (dax_alive(dax_dev) && dax_dev->ops->dax_supported)
+		ret = dax_dev->ops->dax_supported(dax_dev, bdev, blocksize,
+						  start, len);
+	dax_read_unlock(id);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dax_supported);
 #endif /* CONFIG_FS_DAX */
 
 /**
@@ -350,24 +368,6 @@  long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
 }
 EXPORT_SYMBOL_GPL(dax_direct_access);
 
-bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
-		int blocksize, sector_t start, sector_t len)
-{
-	bool ret = false;
-	int id;
-
-	if (!dax_dev)
-		return false;
-
-	id = dax_read_lock();
-	if (dax_alive(dax_dev) && dax_dev->ops->dax_supported)
-		ret = dax_dev->ops->dax_supported(dax_dev, bdev, blocksize,
-						  start, len);
-	dax_read_unlock(id);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(dax_supported);
-
 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 		size_t bytes, struct iov_iter *i)
 {
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 0a3ef9701e03..32dce5763f2c 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -57,8 +57,6 @@  static inline void set_dax_synchronous(struct dax_device *dax_dev)
 {
 	__set_dax_synchronous(dax_dev);
 }
-bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
-		int blocksize, sector_t start, sector_t len);
 /*
  * Check if given mapping is supported by the file / underlying device.
  */
@@ -101,12 +99,6 @@  static inline bool dax_synchronous(struct dax_device *dax_dev)
 static inline void set_dax_synchronous(struct dax_device *dax_dev)
 {
 }
-static inline bool dax_supported(struct dax_device *dax_dev,
-		struct block_device *bdev, int blocksize, sector_t start,
-		sector_t len)
-{
-	return false;
-}
 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
 				struct dax_device *dax_dev)
 {
@@ -127,6 +119,9 @@  bool generic_fsdax_supported(struct dax_device *dax_dev,
 		struct block_device *bdev, int blocksize, sector_t start,
 		sector_t sectors);
 
+bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
+		int blocksize, sector_t start, sector_t len);
+
 static inline void fs_put_dax(struct dax_device *dax_dev)
 {
 	put_dax(dax_dev);
@@ -149,6 +144,13 @@  static inline bool bdev_dax_supported(struct block_device *bdev,
 
 #define generic_fsdax_supported		NULL
 
+static inline bool dax_supported(struct dax_device *dax_dev,
+		struct block_device *bdev, int blocksize, sector_t start,
+		sector_t len)
+{
+	return false;
+}
+
 static inline void fs_put_dax(struct dax_device *dax_dev)
 {
 }