[PATCH v14 5/7] dax: check synchronous mapping is supported
From: Pankaj Gupta <hidden>
Date: 2019-06-21 13:39:50
Also in:
dm-devel, kvm, linux-acpi, linux-fsdevel, linux-xfs, lkml, nvdimm, qemu-devel
Subsystem:
filesystem direct access (dax), the rest · Maintainers:
Dan Williams, Linus Torvalds
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 <redacted> Reviewed-by: Jan Kara <jack@suse.cz> --- include/linux/dax.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 86fc55c99b58..d1bea3979b5a 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h@@ -53,6 +53,18 @@ static inline void set_dax_synchronous(struct dax_device *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 static inline struct dax_device *dax_get_by_host(const char *host) {
@@ -87,6 +99,11 @@ static inline bool 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 struct writeback_control;
--
2.20.1