vnop_map_lloff Entry Point
Purpose
Announces intention to map a file.
Syntax
int vnop_map_lloff (vp, addr, length, offset, mflags, fflags, crp) struct vnode *vp; caddr_t addr; offset_t length; offset_t offset; int mflags; int fflags; struct ucred *crp;
Parameters
| Item | Description |
|---|---|
| vp | Points to the vnode to be queried. |
| addr | Unused. |
| length | Specifies the length of the mapping request. |
| offset | Specifies the starting offset for the map request. |
| mflags | Specifies the mapping flags. |
| fflags | Specifies the file flags. |
| crp | Specifies user's credentials. |
Description
The vnop_map_lloff entry point is used to tell the file system that the file is going to be accessed by memory mapped loads and stores. The file system should fail the request if it does not support memory mapping. This interface allows applications to specify starting offsets that are larger than 2 gigabytes.
File systems that do not define GFS_VERSION421 in their gfs flags do not need to supply a vnop_map_lloff entry point.
Execution Environment
The vnop_map_lloff entry point can be called from the process environment only.
Return Values
| Item | Description |
|---|---|
| Zero | Indicates a successful operation. |
| Nonzero | Indicates that the operation failed; return values should be chosen from the /usr/include/sys/errno.h file. |