4 * (C) Copyright 1995 Linus Torvalds
5 * (C) Copyright 2002 Christoph Hellwig
8 #include <linux/mman.h>
12 static int mlock_fixup(struct vm_area_struct * vma,
13 unsigned long start, unsigned long end, unsigned int newflags)
15 struct mm_struct * mm = vma->vm_mm;
19 if (newflags == vma->vm_flags)
22 if (start != vma->vm_start) {
23 if (split_vma(mm, vma, start, 1)) {
29 if (end != vma->vm_end) {
30 if (split_vma(mm, vma, end, 0)) {
37 * vm_flags is protected by the mmap_sem held in write mode.
38 * It's okay if try_to_unmap_one unmaps a page just after we
39 * set VM_LOCKED, make_pages_present below will bring it back.
41 vma->vm_flags = newflags;
44 * Keep track of amount of locked VM.
46 pages = (end - start) >> PAGE_SHIFT;
47 if (newflags & VM_LOCKED) {
49 ret = make_pages_present(start, end);
52 vma->vm_mm->locked_vm -= pages;
57 static int do_mlock(unsigned long start, size_t len, int on)
59 unsigned long nstart, end, tmp;
60 struct vm_area_struct * vma, * next;
63 len = PAGE_ALIGN(len);
69 vma = find_vma(current->mm, start);
70 if (!vma || vma->vm_start > start)
73 for (nstart = start ; ; ) {
74 unsigned int newflags;
76 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
78 newflags = vma->vm_flags | VM_LOCKED;
80 newflags &= ~VM_LOCKED;
82 if (vma->vm_end >= end) {
83 error = mlock_fixup(vma, nstart, end, newflags);
89 error = mlock_fixup(vma, nstart, tmp, newflags);
94 if (!vma || vma->vm_start != nstart) {
102 asmlinkage long sys_mlock(unsigned long start, size_t len)
104 unsigned long locked;
105 unsigned long lock_limit;
111 down_write(¤t->mm->mmap_sem);
112 len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
115 locked = len >> PAGE_SHIFT;
116 locked += current->mm->locked_vm;
118 lock_limit = current->rlim[RLIMIT_MEMLOCK].rlim_cur;
119 lock_limit >>= PAGE_SHIFT;
121 /* check against resource limits */
122 if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
123 error = do_mlock(start, len, 1);
124 up_write(¤t->mm->mmap_sem);
128 asmlinkage long sys_munlock(unsigned long start, size_t len)
132 down_write(¤t->mm->mmap_sem);
133 len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
135 ret = do_mlock(start, len, 0);
136 up_write(¤t->mm->mmap_sem);
140 static int do_mlockall(int flags)
142 struct vm_area_struct * vma;
143 unsigned int def_flags = 0;
145 if (flags & MCL_FUTURE)
146 def_flags = VM_LOCKED;
147 current->mm->def_flags = def_flags;
148 if (flags == MCL_FUTURE)
151 for (vma = current->mm->mmap; vma ; vma = vma->vm_next) {
152 unsigned int newflags;
154 newflags = vma->vm_flags | VM_LOCKED;
155 if (!(flags & MCL_CURRENT))
156 newflags &= ~VM_LOCKED;
159 mlock_fixup(vma, vma->vm_start, vma->vm_end, newflags);
165 asmlinkage long sys_mlockall(int flags)
167 unsigned long lock_limit;
170 if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
177 down_write(¤t->mm->mmap_sem);
179 lock_limit = current->rlim[RLIMIT_MEMLOCK].rlim_cur;
180 lock_limit >>= PAGE_SHIFT;
183 if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
184 capable(CAP_IPC_LOCK))
185 ret = do_mlockall(flags);
186 up_write(¤t->mm->mmap_sem);
191 asmlinkage long sys_munlockall(void)
195 down_write(¤t->mm->mmap_sem);
196 ret = do_mlockall(0);
197 up_write(¤t->mm->mmap_sem);
202 * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB
203 * shm segments) get accounted against the user_struct instead.
205 static spinlock_t shmlock_user_lock = SPIN_LOCK_UNLOCKED;
207 int user_shm_lock(size_t size, struct user_struct *user)
209 unsigned long lock_limit, locked;
212 spin_lock(&shmlock_user_lock);
213 locked = size >> PAGE_SHIFT;
214 lock_limit = current->rlim[RLIMIT_MEMLOCK].rlim_cur;
215 lock_limit >>= PAGE_SHIFT;
216 if (locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
219 user->locked_shm += locked;
222 spin_unlock(&shmlock_user_lock);
226 void user_shm_unlock(size_t size, struct user_struct *user)
228 spin_lock(&shmlock_user_lock);
229 user->locked_shm -= (size >> PAGE_SHIFT);
230 spin_unlock(&shmlock_user_lock);