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| -rw-r--r-- | Documentation/filesystems/porting.rst | 5 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.rst | 4 |
2 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst index 7233b04668fc..b7ddf89103c7 100644 --- a/Documentation/filesystems/porting.rst +++ b/Documentation/filesystems/porting.rst @@ -1286,6 +1286,11 @@ The vm_area_desc provides the minimum required information for a filesystem to initialise state upon memory mapping of a file-backed region, and output parameters for the file system to set this state. +In nearly all cases, this is all that is required for a filesystem. However, if +a filesystem needs to perform an operation such a pre-population of page tables, +then that action can be specified in the vm_area_desc->action field, which can +be configured using the mmap_action_*() helpers. + --- **mandatory** diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index 4f13b01e42eb..670ba66b60e4 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -1213,6 +1213,10 @@ otherwise noted. file-backed memory mapping, most notably establishing relevant private state and VMA callbacks. + If further action such as pre-population of page tables is required, + this can be specified by the vm_area_desc->action field and related + parameters. + Note that the file operations are implemented by the specific filesystem in which the inode resides. When opening a device node (character or block special) most filesystems will call special |