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Message-Id: <20190621133455.3303-6-pagupta@redhat.com>
Date: Fri, 21 Jun 2019 19:04:53 +0530
From: Pankaj Gupta <pagupta@...hat.com>
To: dm-devel@...hat.com, linux-nvdimm@...ts.01.org,
linux-kernel@...r.kernel.org,
virtualization@...ts.linux-foundation.org, kvm@...r.kernel.org,
linux-fsdevel@...r.kernel.org, linux-acpi@...r.kernel.org,
qemu-devel@...gnu.org, linux-ext4@...r.kernel.org,
linux-xfs@...r.kernel.org
Cc: dan.j.williams@...el.com, zwisler@...nel.org,
vishal.l.verma@...el.com, dave.jiang@...el.com, mst@...hat.com,
jasowang@...hat.com, willy@...radead.org, rjw@...ysocki.net,
hch@...radead.org, lenb@...nel.org, jack@...e.cz, tytso@....edu,
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Subject: [PATCH v14 5/7] 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@...e.cz>
Signed-off-by: Pankaj Gupta <pagupta@...hat.com>
Reviewed-by: Jan Kara <jack@...e.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
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