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dax: check synchronous mapping is supported 

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>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Pankaj Gupta 2019-07-05 19:33:26 +05:30 committed by Dan Williams
parent 2e9ee0955d
commit 32de148464
1 changed files with 17 additions and 0 deletions
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17
include/linux/dax.h
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@ -56,6 +56,18 @@ static inline void set_dax_synchronous(struct dax_device *dax_dev)
{ {
__set_dax_synchronous(dax_dev); __set_dax_synchronous(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 #else
static inline struct dax_device *dax_get_by_host(const char *host) static inline struct dax_device *dax_get_by_host(const char *host)
{ {
@ -90,6 +102,11 @@ static inline bool dax_synchronous(struct dax_device *dax_dev)
static inline void set_dax_synchronous(struct dax_device *dax_dev) static inline void set_dax_synchronous(struct dax_device *dax_dev)
{ {
} }
static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
struct dax_device *dax_dev)
{
return !(vma->vm_flags & VM_SYNC);
}
#endif #endif
struct writeback_control; struct writeback_control;