1 // SPDX-License-Identifier: GPL-2.0
5  * Copyright (C) 1994-1999  Linus Torvalds
19  * MS_SYNC syncs the entire file - including mappings.
21  * MS_ASYNC does not start I/O (it used to, up to 2.5.67).
22  * Nor does it marks the relevant pages dirty (it used to up to 2.6.17).
27  * Or the application may run fadvise(FADV_DONTNEED) against the fd to start
32 SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)  in SYSCALL_DEFINE3()  argument
35 	struct mm_struct *mm = current->mm;  in SYSCALL_DEFINE3()
38 	int error = -EINVAL;  in SYSCALL_DEFINE3()
40 	start = untagged_addr(start);  in SYSCALL_DEFINE3()
44 	if (offset_in_page(start))  in SYSCALL_DEFINE3()
48 	error = -ENOMEM;  in SYSCALL_DEFINE3()
50 	end = start + len;  in SYSCALL_DEFINE3()
51 	if (end < start)  in SYSCALL_DEFINE3()
54 	if (end == start)  in SYSCALL_DEFINE3()
57 	 * If the interval [start,end) covers some unmapped address ranges,  in SYSCALL_DEFINE3()
58 	 * just ignore them, but return -ENOMEM at the end.  in SYSCALL_DEFINE3()
61 	vma = find_vma(mm, start);  in SYSCALL_DEFINE3()
66 		/* Still start < end. */  in SYSCALL_DEFINE3()
67 		error = -ENOMEM;  in SYSCALL_DEFINE3()
70 		/* Here start < vma->vm_end. */  in SYSCALL_DEFINE3()
71 		if (start < vma->vm_start) {  in SYSCALL_DEFINE3()
72 			start = vma->vm_start;  in SYSCALL_DEFINE3()
73 			if (start >= end)  in SYSCALL_DEFINE3()
75 			unmapped_error = -ENOMEM;  in SYSCALL_DEFINE3()
77 		/* Here vma->vm_start <= start < vma->vm_end. */  in SYSCALL_DEFINE3()
79 				(vma->vm_flags & VM_LOCKED)) {  in SYSCALL_DEFINE3()
80 			error = -EBUSY;  in SYSCALL_DEFINE3()
83 		file = vma->vm_file;  in SYSCALL_DEFINE3()
84 		fstart = (start - vma->vm_start) +  in SYSCALL_DEFINE3()
85 			 ((loff_t)vma->vm_pgoff << PAGE_SHIFT);  in SYSCALL_DEFINE3()
86 		fend = fstart + (min(end, vma->vm_end) - start) - 1;  in SYSCALL_DEFINE3()
87 		start = vma->vm_end;  in SYSCALL_DEFINE3()
89 				(vma->vm_flags & VM_SHARED)) {  in SYSCALL_DEFINE3()
94 			if (error || start >= end)  in SYSCALL_DEFINE3()
97 			vma = find_vma(mm, start);  in SYSCALL_DEFINE3()
99 			if (start >= end) {  in SYSCALL_DEFINE3()
103 			vma = vma->vm_next;  in SYSCALL_DEFINE3()