4 * (C) Copyright 1995 Linus Torvalds
5 * (C) Copyright 2002 Christoph Hellwig
8 #include <linux/mman.h>
10 #include <linux/mempolicy.h>
11 #include <linux/syscalls.h>
12 #include <linux/vs_memory.h>
15 static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
16 unsigned long start, unsigned long end, unsigned int newflags)
18 struct mm_struct * mm = vma->vm_mm;
23 if (newflags == vma->vm_flags) {
28 pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
29 *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
30 vma->vm_file, pgoff, vma_policy(vma));
38 if (start != vma->vm_start) {
39 ret = split_vma(mm, vma, start, 1);
44 if (end != vma->vm_end) {
45 ret = split_vma(mm, vma, end, 0);
52 * vm_flags is protected by the mmap_sem held in write mode.
53 * It's okay if try_to_unmap_one unmaps a page just after we
54 * set VM_LOCKED, make_pages_present below will bring it back.
56 vma->vm_flags = newflags;
59 * Keep track of amount of locked VM.
61 pages = (end - start) >> PAGE_SHIFT;
62 if (newflags & VM_LOCKED) {
64 if (!(newflags & VM_IO))
65 ret = make_pages_present(start, end);
68 vx_vmlocked_sub(vma->vm_mm, pages);
75 static int do_mlock(unsigned long start, size_t len, int on)
77 unsigned long nstart, end, tmp;
78 struct vm_area_struct * vma, * prev;
81 len = PAGE_ALIGN(len);
87 vma = find_vma_prev(current->mm, start, &prev);
88 if (!vma || vma->vm_start > start)
91 if (start > vma->vm_start)
94 for (nstart = start ; ; ) {
95 unsigned int newflags;
97 /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
99 newflags = vma->vm_flags | VM_LOCKED;
101 newflags &= ~VM_LOCKED;
106 error = mlock_fixup(vma, &prev, nstart, tmp, newflags);
110 if (nstart < prev->vm_end)
111 nstart = prev->vm_end;
116 if (!vma || vma->vm_start != nstart) {
124 asmlinkage long sys_mlock(unsigned long start, size_t len)
126 unsigned long locked, grow;
127 unsigned long lock_limit;
133 down_write(¤t->mm->mmap_sem);
134 len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
137 grow = len >> PAGE_SHIFT;
138 if (!vx_vmlocked_avail(current->mm, grow))
140 locked = current->mm->locked_vm + grow;
142 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
143 lock_limit >>= PAGE_SHIFT;
145 /* check against resource limits */
146 if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
147 error = do_mlock(start, len, 1);
149 up_write(¤t->mm->mmap_sem);
153 asmlinkage long sys_munlock(unsigned long start, size_t len)
157 down_write(¤t->mm->mmap_sem);
158 len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
160 ret = do_mlock(start, len, 0);
161 up_write(¤t->mm->mmap_sem);
165 static int do_mlockall(int flags)
167 struct vm_area_struct * vma, * prev = NULL;
168 unsigned int def_flags = 0;
170 if (flags & MCL_FUTURE)
171 def_flags = VM_LOCKED;
172 current->mm->def_flags = def_flags;
173 if (flags == MCL_FUTURE)
176 for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
177 unsigned int newflags;
179 newflags = vma->vm_flags | VM_LOCKED;
180 if (!(flags & MCL_CURRENT))
181 newflags &= ~VM_LOCKED;
184 mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
190 asmlinkage long sys_mlockall(int flags)
192 unsigned long lock_limit;
195 if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
202 down_write(¤t->mm->mmap_sem);
204 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
205 lock_limit >>= PAGE_SHIFT;
208 if (!vx_vmlocked_avail(current->mm, current->mm->total_vm))
210 if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
211 capable(CAP_IPC_LOCK))
212 ret = do_mlockall(flags);
213 up_write(¤t->mm->mmap_sem);
218 asmlinkage long sys_munlockall(void)
222 down_write(¤t->mm->mmap_sem);
223 ret = do_mlockall(0);
224 up_write(¤t->mm->mmap_sem);
229 * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB
230 * shm segments) get accounted against the user_struct instead.
232 static DEFINE_SPINLOCK(shmlock_user_lock);
234 int user_shm_lock(size_t size, struct user_struct *user)
236 unsigned long lock_limit, locked;
239 locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
240 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
241 lock_limit >>= PAGE_SHIFT;
242 spin_lock(&shmlock_user_lock);
243 if (locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
246 user->locked_shm += locked;
249 spin_unlock(&shmlock_user_lock);
253 void user_shm_unlock(size_t size, struct user_struct *user)
255 spin_lock(&shmlock_user_lock);
256 user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
257 spin_unlock(&shmlock_user_lock);