From bd85b79604eaf88ead3641f4823aa0bedcfdfe96 Mon Sep 17 00:00:00 2001 From: Pankaj Gupta Date: Fri, 5 Jul 2019 19:33:26 +0530 Subject: [PATCH 0993/2944] dax: check synchronous mapping is supported fix #27138800 commit 32de1484648a837db5dea0a7007fe7136804e392 upstream. 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 Signed-off-by: Pankaj Gupta Reviewed-by: Jan Kara Signed-off-by: Dan Williams Reviewed-by: Yang Shi Signed-off-by: Xunlei Pang --- include/linux/dax.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/include/linux/dax.h b/include/linux/dax.h index 099d20b..ae06a6c 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -48,6 +48,18 @@ 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) { @@ -82,6 +94,11 @@ 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; -- 1.8.3.1