[v7,4/6] dax: check synchronous mapping is supported
diff mbox series

Message ID 20190426050039.17460-5-pagupta@redhat.com
State Superseded
Headers show
Series
  • virtio pmem driver
Related show

Commit Message

Pankaj Gupta April 26, 2019, 5 a.m. UTC
This patch introduces 'daxdev_mapping_supported' helper
which checks if 'MAP_SYNC' is supported with filesystem
mapping. It also checks if corresponding dax_device is
synchronous. Virtio pmem device is asynchronous and
does not not support VM_SYNC. 

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 include/linux/dax.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Comments

Jakub StaroĊ„ May 7, 2019, 7:24 p.m. UTC | #1
From: Pankaj Gupta <pagupta@redhat.com>
Date: Thu, Apr 25, 2019 at 10:00 PM

> +static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
> +                               struct dax_device *dax_dev)
> +{
> +       return !(vma->flags & VM_SYNC);
> +}

Shouldn't it be rather `return !(vma->vm_flags & VM_SYNC);`? There is
no field named `flags` in `struct vm_area_struct`.

Thank you,
Jakub
Pankaj Gupta May 8, 2019, 5:31 a.m. UTC | #2
> 
> From: Pankaj Gupta <pagupta@redhat.com>
> Date: Thu, Apr 25, 2019 at 10:00 PM
> 
> > +static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
> > +                               struct dax_device *dax_dev)
> > +{
> > +       return !(vma->flags & VM_SYNC);
> > +}
> 
> Shouldn't it be rather `return !(vma->vm_flags & VM_SYNC);`? There is
> no field named `flags` in `struct vm_area_struct`.

Thanks for catching. Sorry! for this. 

Will correct in v8.

Thank you,
Pankaj 

> 
> Thank you,
> Jakub
>

Patch
diff mbox series

diff --git a/include/linux/dax.h b/include/linux/dax.h
index c97fc0cc7167..41b4a5db6305 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -41,6 +41,18 @@  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);
+/*
+ * Check if given mapping is supported by the file / underlying device.
+ */
+static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
+				struct dax_device *dax_dev)
+{
+	if (!(vma->vm_flags & VM_SYNC))
+		return true;
+	if (!IS_DAX(file_inode(vma->vm_file)))
+		return false;
+	return dax_synchronous(dax_dev);
+}
 #else
 static inline struct dax_device *dax_get_by_host(const char *host)
 {
@@ -68,6 +80,11 @@  static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
 {
 	return false;
 }
+static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
+				struct dax_device *dax_dev)
+{
+	return !(vma->flags & VM_SYNC);
+}
 #endif
 
 struct writeback_control;