4 * (C) Copyright 1995 Linus Torvalds
5 * (C) Copyright 2002 Christoph Hellwig
8 #include <linux/capability.h>
9 #include <linux/mman.h>
11 #include <linux/mempolicy.h>
12 #include <linux/syscalls.h>
13 #include <linux/vs_base.h>
14 #include <linux/vs_memory.h>
17 static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
18 unsigned long start, unsigned long end, unsigned int newflags)
20 struct mm_struct * mm = vma->vm_mm;
25 if (newflags == vma->vm_flags) {
30 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
31 *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
32 vma->vm_file, pgoff, vma_policy(vma));
40 if (start != vma->vm_start) {
41 ret = split_vma(mm, vma, start, 1);
46 if (end != vma->vm_end) {
47 ret = split_vma(mm, vma, end, 0);
54 * vm_flags is protected by the mmap_sem held in write mode.
55 * It's okay if try_to_unmap_one unmaps a page just after we
56 * set VM_LOCKED, make_pages_present below will bring it back.
58 vma->vm_flags = newflags;
61 * Keep track of amount of locked VM.
63 pages = (end - start) >> PAGE_SHIFT;
64 if (newflags & VM_LOCKED) {
66 if (!(newflags & VM_IO))
67 ret = make_pages_present(start, end);
70 vx_vmlocked_sub(mm, pages);
77 static int do_mlock(unsigned long start, size_t len, int on)
79 unsigned long nstart, end, tmp;
80 struct vm_area_struct * vma, * prev;
83 len = PAGE_ALIGN(len);
89 vma = find_vma_prev(current->mm, start, &prev);
90 if (!vma || vma->vm_start > start)
93 if (start > vma->vm_start)
96 for (nstart = start ; ; ) {
97 unsigned int newflags;
99 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
101 newflags = vma->vm_flags | VM_LOCKED;
103 newflags &= ~VM_LOCKED;
108 error = mlock_fixup(vma, &prev, nstart, tmp, newflags);
112 if (nstart < prev->vm_end)
113 nstart = prev->vm_end;
118 if (!vma || vma->vm_start != nstart) {
126 asmlinkage long sys_mlock(unsigned long start, size_t len)
128 unsigned long locked, grow;
129 unsigned long lock_limit;
135 down_write(¤t->mm->mmap_sem);
136 len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
139 grow = len >> PAGE_SHIFT;
140 if (!vx_vmlocked_avail(current->mm, grow))
142 locked = current->mm->locked_vm + grow;
144 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
145 lock_limit >>= PAGE_SHIFT;
147 /* check against resource limits */
148 if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
149 error = do_mlock(start, len, 1);
151 up_write(¤t->mm->mmap_sem);
155 asmlinkage long sys_munlock(unsigned long start, size_t len)
159 down_write(¤t->mm->mmap_sem);
160 len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
162 ret = do_mlock(start, len, 0);
163 up_write(¤t->mm->mmap_sem);
167 static int do_mlockall(int flags)
169 struct vm_area_struct * vma, * prev = NULL;
170 unsigned int def_flags = 0;
172 if (flags & MCL_FUTURE)
173 def_flags = VM_LOCKED;
174 current->mm->def_flags = def_flags;
175 if (flags == MCL_FUTURE)
178 for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
179 unsigned int newflags;
181 newflags = vma->vm_flags | VM_LOCKED;
182 if (!(flags & MCL_CURRENT))
183 newflags &= ~VM_LOCKED;
186 mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
192 asmlinkage long sys_mlockall(int flags)
194 unsigned long lock_limit;
197 if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
204 down_write(¤t->mm->mmap_sem);
206 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
207 lock_limit >>= PAGE_SHIFT;
210 if (!vx_vmlocked_avail(current->mm, current->mm->total_vm))
212 if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
213 capable(CAP_IPC_LOCK))
214 ret = do_mlockall(flags);
215 up_write(¤t->mm->mmap_sem);
220 asmlinkage long sys_munlockall(void)
224 down_write(¤t->mm->mmap_sem);
225 ret = do_mlockall(0);
226 up_write(¤t->mm->mmap_sem);
231 * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB
232 * shm segments) get accounted against the user_struct instead.
234 static DEFINE_SPINLOCK(shmlock_user_lock);
236 int user_shm_lock(size_t size, struct user_struct *user)
238 unsigned long lock_limit, locked;
241 locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
242 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
243 lock_limit >>= PAGE_SHIFT;
244 spin_lock(&shmlock_user_lock);
245 if (locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
248 user->locked_shm += locked;
251 spin_unlock(&shmlock_user_lock);
255 void user_shm_unlock(size_t size, struct user_struct *user)
257 spin_lock(&shmlock_user_lock);
258 user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
259 spin_unlock(&shmlock_user_lock);