[v5,3/6] libnvdimm: add dax_dev sync flag
diff mbox series

Message ID 20190410040826.24371-4-pagupta@redhat.com
State Superseded
Headers show
Series
  • virtio pmem driver
Related show

Commit Message

Pankaj Gupta April 10, 2019, 4:08 a.m. UTC
This patch adds 'DAXDEV_SYNC' flag which is set
for nd_region doing synchronous flush. This later
is used to disable MAP_SYNC functionality for
ext4 & xfs filesystem for devices don't support
synchronous flush.

Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
---
 drivers/dax/bus.c            |  2 +-
 drivers/dax/super.c          | 13 ++++++++++++-
 drivers/md/dm.c              |  2 +-
 drivers/nvdimm/pmem.c        |  3 ++-
 drivers/nvdimm/region_devs.c |  7 +++++++
 include/linux/dax.h          |  9 +++++++--
 include/linux/libnvdimm.h    |  1 +
 7 files changed, 31 insertions(+), 6 deletions(-)

Comments

Jan Kara April 10, 2019, 8:28 a.m. UTC | #1
On Wed 10-04-19 09:38:23, Pankaj Gupta wrote:
> @@ -64,6 +65,10 @@ static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
>  {
>  	return false;
>  }
> +static inline bool dax_synchronous(struct dax_device *dax_dev)
> +{
> +	return true;
> +}

Is there a need to define dax_synchronous() for !CONFIG_DAX? Because that
property of dax device is pretty much undefined and I don't see anything
needing to call it for !CONFIG_DAX...

								Honza
Pankaj Gupta April 10, 2019, 8:38 a.m. UTC | #2
> 
> On Wed 10-04-19 09:38:23, Pankaj Gupta wrote:
> > @@ -64,6 +65,10 @@ static inline bool dax_write_cache_enabled(struct
> > dax_device *dax_dev)
> >  {
> >  	return false;
> >  }
> > +static inline bool dax_synchronous(struct dax_device *dax_dev)
> > +{
> > +	return true;
> > +}
> 
> Is there a need to define dax_synchronous() for !CONFIG_DAX? Because that
> property of dax device is pretty much undefined and I don't see anything
> needing to call it for !CONFIG_DAX...

You are right. Will remove this.

Thanks for the review.

Best regards,
Pankaj

> 
> 								Honza
> --
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
>
Dan Williams April 11, 2019, 2:56 p.m. UTC | #3
On Tue, Apr 9, 2019 at 9:10 PM Pankaj Gupta <pagupta@redhat.com> wrote:
>
> This patch adds 'DAXDEV_SYNC' flag which is set
> for nd_region doing synchronous flush. This later
> is used to disable MAP_SYNC functionality for
> ext4 & xfs filesystem for devices don't support
> synchronous flush.
>
> Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
> ---
>  drivers/dax/bus.c            |  2 +-
>  drivers/dax/super.c          | 13 ++++++++++++-
>  drivers/md/dm.c              |  2 +-
>  drivers/nvdimm/pmem.c        |  3 ++-
>  drivers/nvdimm/region_devs.c |  7 +++++++
>  include/linux/dax.h          |  9 +++++++--
>  include/linux/libnvdimm.h    |  1 +
>  7 files changed, 31 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
> index 2109cfe80219..431bf7d2a7f9 100644
> --- a/drivers/dax/bus.c
> +++ b/drivers/dax/bus.c
> @@ -388,7 +388,7 @@ struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id,
>          * No 'host' or dax_operations since there is no access to this
>          * device outside of mmap of the resulting character device.
>          */
> -       dax_dev = alloc_dax(dev_dax, NULL, NULL);
> +       dax_dev = alloc_dax(dev_dax, NULL, NULL, true);

I find apis that take a boolean as unreadable. What does 'true' mean?
It wastes time to go look at the function definition vs something
like:

    alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC);
Pankaj Gupta April 11, 2019, 3:39 p.m. UTC | #4
Hi Dan,

Thank you for the review.

> >
> > This patch adds 'DAXDEV_SYNC' flag which is set
> > for nd_region doing synchronous flush. This later
> > is used to disable MAP_SYNC functionality for
> > ext4 & xfs filesystem for devices don't support
> > synchronous flush.
> >
> > Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
> > ---
> >  drivers/dax/bus.c            |  2 +-
> >  drivers/dax/super.c          | 13 ++++++++++++-
> >  drivers/md/dm.c              |  2 +-
> >  drivers/nvdimm/pmem.c        |  3 ++-
> >  drivers/nvdimm/region_devs.c |  7 +++++++
> >  include/linux/dax.h          |  9 +++++++--
> >  include/linux/libnvdimm.h    |  1 +
> >  7 files changed, 31 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
> > index 2109cfe80219..431bf7d2a7f9 100644
> > --- a/drivers/dax/bus.c
> > +++ b/drivers/dax/bus.c
> > @@ -388,7 +388,7 @@ struct dev_dax *__devm_create_dev_dax(struct dax_region
> > *dax_region, int id,
> >          * No 'host' or dax_operations since there is no access to this
> >          * device outside of mmap of the resulting character device.
> >          */
> > -       dax_dev = alloc_dax(dev_dax, NULL, NULL);
> > +       dax_dev = alloc_dax(dev_dax, NULL, NULL, true);
> 
> I find apis that take a boolean as unreadable. What does 'true' mean?
> It wastes time to go look at the function definition vs something
> like:
> 
>     alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC);

Agree. Will change as suggested.

Best regards,
Pankaj
>

Patch
diff mbox series

diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 2109cfe80219..431bf7d2a7f9 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -388,7 +388,7 @@  struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id,
 	 * No 'host' or dax_operations since there is no access to this
 	 * device outside of mmap of the resulting character device.
 	 */
-	dax_dev = alloc_dax(dev_dax, NULL, NULL);
+	dax_dev = alloc_dax(dev_dax, NULL, NULL, true);
 	if (!dax_dev)
 		goto err;
 
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 0a339b85133e..bd6509308d05 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -186,6 +186,8 @@  enum dax_device_flags {
 	DAXDEV_ALIVE,
 	/* gate whether dax_flush() calls the low level flush routine */
 	DAXDEV_WRITE_CACHE,
+	/* flag to check if device supports synchronous flush */
+	DAXDEV_SYNC,
 };
 
 /**
@@ -354,6 +356,12 @@  bool dax_write_cache_enabled(struct dax_device *dax_dev)
 }
 EXPORT_SYMBOL_GPL(dax_write_cache_enabled);
 
+bool dax_synchronous(struct dax_device *dax_dev)
+{
+	return test_bit(DAXDEV_SYNC, &dax_dev->flags);
+}
+EXPORT_SYMBOL_GPL(dax_synchronous);
+
 bool dax_alive(struct dax_device *dax_dev)
 {
 	lockdep_assert_held(&dax_srcu);
@@ -511,7 +519,7 @@  static void dax_add_host(struct dax_device *dax_dev, const char *host)
 }
 
 struct dax_device *alloc_dax(void *private, const char *__host,
-		const struct dax_operations *ops)
+		const struct dax_operations *ops, bool sync)
 {
 	struct dax_device *dax_dev;
 	const char *host;
@@ -534,6 +542,9 @@  struct dax_device *alloc_dax(void *private, const char *__host,
 	dax_add_host(dax_dev, host);
 	dax_dev->ops = ops;
 	dax_dev->private = private;
+	if (sync)
+		set_bit(DAXDEV_SYNC, &dax_dev->flags);
+
 	return dax_dev;
 
  err_dev:
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 68d24056d0b1..534e12ca6329 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1965,7 +1965,7 @@  static struct mapped_device *alloc_dev(int minor)
 	sprintf(md->disk->disk_name, "dm-%d", minor);
 
 	if (IS_ENABLED(CONFIG_DAX_DRIVER)) {
-		dax_dev = alloc_dax(md, md->disk->disk_name, &dm_dax_ops);
+		dax_dev = alloc_dax(md, md->disk->disk_name, &dm_dax_ops, true);
 		if (!dax_dev)
 			goto bad;
 	}
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 5a5b3ea4d073..78f71ba0e7cf 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -466,7 +466,8 @@  static int pmem_attach_disk(struct device *dev,
 	nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_res);
 	disk->bb = &pmem->bb;
 
-	dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops);
+	dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops,
+					is_nvdimm_sync(nd_region));
 
 	if (!dax_dev) {
 		put_disk(disk);
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index fb1041ab32a6..8c7aa047fe2b 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -1231,6 +1231,13 @@  int nvdimm_has_cache(struct nd_region *nd_region)
 }
 EXPORT_SYMBOL_GPL(nvdimm_has_cache);
 
+bool is_nvdimm_sync(struct nd_region *nd_region)
+{
+	return is_nd_pmem(&nd_region->dev) &&
+		!test_bit(ND_REGION_ASYNC, &nd_region->flags);
+}
+EXPORT_SYMBOL_GPL(is_nvdimm_sync);
+
 struct conflict_context {
 	struct nd_region *nd_region;
 	resource_size_t start, size;
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 0dd316a74a29..b896706a5ee9 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -32,18 +32,19 @@  extern struct attribute_group dax_attribute_group;
 #if IS_ENABLED(CONFIG_DAX)
 struct dax_device *dax_get_by_host(const char *host);
 struct dax_device *alloc_dax(void *private, const char *host,
-		const struct dax_operations *ops);
+		const struct dax_operations *ops, bool sync);
 void put_dax(struct dax_device *dax_dev);
 void kill_dax(struct dax_device *dax_dev);
 void dax_write_cache(struct dax_device *dax_dev, bool wc);
 bool dax_write_cache_enabled(struct dax_device *dax_dev);
+bool dax_synchronous(struct dax_device *dax_dev);
 #else
 static inline struct dax_device *dax_get_by_host(const char *host)
 {
 	return NULL;
 }
 static inline struct dax_device *alloc_dax(void *private, const char *host,
-		const struct dax_operations *ops)
+		const struct dax_operations *ops, bool sync)
 {
 	/*
 	 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
@@ -64,6 +65,10 @@  static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
 {
 	return false;
 }
+static inline bool dax_synchronous(struct dax_device *dax_dev)
+{
+	return true;
+}
 #endif
 
 struct writeback_control;
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index d9d2ab8a6e64..9a8aea370cbc 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -270,6 +270,7 @@  int generic_nvdimm_flush(struct nd_region *nd_region);
 int nvdimm_has_flush(struct nd_region *nd_region);
 int nvdimm_has_cache(struct nd_region *nd_region);
 int nvdimm_in_overwrite(struct nvdimm *nvdimm);
+bool is_nvdimm_sync(struct nd_region *nd_region);
 
 static inline int nvdimm_ctl(struct nvdimm *nvdimm, unsigned int cmd, void *buf,
 		unsigned int buf_len, int *cmd_rc)