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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /mm/mlock.c
downloadlinux-2.6.34-ux500-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'mm/mlock.c')
-rw-r--r--mm/mlock.c253
1 files changed, 253 insertions, 0 deletions
diff --git a/mm/mlock.c b/mm/mlock.c
new file mode 100644
index 00000000000..4ae3a46ff76
--- /dev/null
+++ b/mm/mlock.c
@@ -0,0 +1,253 @@
+/*
+ * linux/mm/mlock.c
+ *
+ * (C) Copyright 1995 Linus Torvalds
+ * (C) Copyright 2002 Christoph Hellwig
+ */
+
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/mempolicy.h>
+#include <linux/syscalls.h>
+
+
+static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
+ unsigned long start, unsigned long end, unsigned int newflags)
+{
+ struct mm_struct * mm = vma->vm_mm;
+ pgoff_t pgoff;
+ int pages;
+ int ret = 0;
+
+ if (newflags == vma->vm_flags) {
+ *prev = vma;
+ goto out;
+ }
+
+ pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
+ *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
+ vma->vm_file, pgoff, vma_policy(vma));
+ if (*prev) {
+ vma = *prev;
+ goto success;
+ }
+
+ *prev = vma;
+
+ if (start != vma->vm_start) {
+ ret = split_vma(mm, vma, start, 1);
+ if (ret)
+ goto out;
+ }
+
+ if (end != vma->vm_end) {
+ ret = split_vma(mm, vma, end, 0);
+ if (ret)
+ goto out;
+ }
+
+success:
+ /*
+ * vm_flags is protected by the mmap_sem held in write mode.
+ * It's okay if try_to_unmap_one unmaps a page just after we
+ * set VM_LOCKED, make_pages_present below will bring it back.
+ */
+ vma->vm_flags = newflags;
+
+ /*
+ * Keep track of amount of locked VM.
+ */
+ pages = (end - start) >> PAGE_SHIFT;
+ if (newflags & VM_LOCKED) {
+ pages = -pages;
+ if (!(newflags & VM_IO))
+ ret = make_pages_present(start, end);
+ }
+
+ vma->vm_mm->locked_vm -= pages;
+out:
+ if (ret == -ENOMEM)
+ ret = -EAGAIN;
+ return ret;
+}
+
+static int do_mlock(unsigned long start, size_t len, int on)
+{
+ unsigned long nstart, end, tmp;
+ struct vm_area_struct * vma, * prev;
+ int error;
+
+ len = PAGE_ALIGN(len);
+ end = start + len;
+ if (end < start)
+ return -EINVAL;
+ if (end == start)
+ return 0;
+ vma = find_vma_prev(current->mm, start, &prev);
+ if (!vma || vma->vm_start > start)
+ return -ENOMEM;
+
+ if (start > vma->vm_start)
+ prev = vma;
+
+ for (nstart = start ; ; ) {
+ unsigned int newflags;
+
+ /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
+
+ newflags = vma->vm_flags | VM_LOCKED;
+ if (!on)
+ newflags &= ~VM_LOCKED;
+
+ tmp = vma->vm_end;
+ if (tmp > end)
+ tmp = end;
+ error = mlock_fixup(vma, &prev, nstart, tmp, newflags);
+ if (error)
+ break;
+ nstart = tmp;
+ if (nstart < prev->vm_end)
+ nstart = prev->vm_end;
+ if (nstart >= end)
+ break;
+
+ vma = prev->vm_next;
+ if (!vma || vma->vm_start != nstart) {
+ error = -ENOMEM;
+ break;
+ }
+ }
+ return error;
+}
+
+asmlinkage long sys_mlock(unsigned long start, size_t len)
+{
+ unsigned long locked;
+ unsigned long lock_limit;
+ int error = -ENOMEM;
+
+ if (!can_do_mlock())
+ return -EPERM;
+
+ down_write(&current->mm->mmap_sem);
+ len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
+ start &= PAGE_MASK;
+
+ locked = len >> PAGE_SHIFT;
+ locked += current->mm->locked_vm;
+
+ lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+ lock_limit >>= PAGE_SHIFT;
+
+ /* check against resource limits */
+ if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
+ error = do_mlock(start, len, 1);
+ up_write(&current->mm->mmap_sem);
+ return error;
+}
+
+asmlinkage long sys_munlock(unsigned long start, size_t len)
+{
+ int ret;
+
+ down_write(&current->mm->mmap_sem);
+ len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
+ start &= PAGE_MASK;
+ ret = do_mlock(start, len, 0);
+ up_write(&current->mm->mmap_sem);
+ return ret;
+}
+
+static int do_mlockall(int flags)
+{
+ struct vm_area_struct * vma, * prev = NULL;
+ unsigned int def_flags = 0;
+
+ if (flags & MCL_FUTURE)
+ def_flags = VM_LOCKED;
+ current->mm->def_flags = def_flags;
+ if (flags == MCL_FUTURE)
+ goto out;
+
+ for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
+ unsigned int newflags;
+
+ newflags = vma->vm_flags | VM_LOCKED;
+ if (!(flags & MCL_CURRENT))
+ newflags &= ~VM_LOCKED;
+
+ /* Ignore errors */
+ mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
+ }
+out:
+ return 0;
+}
+
+asmlinkage long sys_mlockall(int flags)
+{
+ unsigned long lock_limit;
+ int ret = -EINVAL;
+
+ if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
+ goto out;
+
+ ret = -EPERM;
+ if (!can_do_mlock())
+ goto out;
+
+ down_write(&current->mm->mmap_sem);
+
+ lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+ lock_limit >>= PAGE_SHIFT;
+
+ ret = -ENOMEM;
+ if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
+ capable(CAP_IPC_LOCK))
+ ret = do_mlockall(flags);
+ up_write(&current->mm->mmap_sem);
+out:
+ return ret;
+}
+
+asmlinkage long sys_munlockall(void)
+{
+ int ret;
+
+ down_write(&current->mm->mmap_sem);
+ ret = do_mlockall(0);
+ up_write(&current->mm->mmap_sem);
+ return ret;
+}
+
+/*
+ * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB
+ * shm segments) get accounted against the user_struct instead.
+ */
+static DEFINE_SPINLOCK(shmlock_user_lock);
+
+int user_shm_lock(size_t size, struct user_struct *user)
+{
+ unsigned long lock_limit, locked;
+ int allowed = 0;
+
+ locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+ lock_limit >>= PAGE_SHIFT;
+ spin_lock(&shmlock_user_lock);
+ if (locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
+ goto out;
+ get_uid(user);
+ user->locked_shm += locked;
+ allowed = 1;
+out:
+ spin_unlock(&shmlock_user_lock);
+ return allowed;
+}
+
+void user_shm_unlock(size_t size, struct user_struct *user)
+{
+ spin_lock(&shmlock_user_lock);
+ user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ spin_unlock(&shmlock_user_lock);
+ free_uid(user);
+}