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!

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);
+}