patch-1.3.43 linux/mm/mlock.c

• Lines: 271
• Date: Tue Nov 21 09:58:24 1995
• Orig file: v1.3.42/linux/mm/mlock.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.42/linux/mm/mlock.c linux/mm/mlock.c
@@ -0,0 +1,270 @@
+/*
+ *	linux/mm/mlock.c
+ *
+ *  (C) Copyright 1995 Linus Torvalds
+ */
+#include <linux/stat.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/shm.h>
+#include <linux/errno.h>
+#include <linux/mman.h>
+#include <linux/string.h>
+#include <linux/malloc.h>
+
+#include <asm/segment.h>
+#include <asm/system.h>
+#include <asm/pgtable.h>
+
+static inline int mlock_fixup_all(struct vm_area_struct * vma, int newflags)
+{
+	vma->vm_flags = newflags;
+	return 0;
+}
+
+static inline int mlock_fixup_start(struct vm_area_struct * vma,
+	unsigned long end, int newflags)
+{
+	struct vm_area_struct * n;
+
+	n = (struct vm_area_struct *) kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
+	if (!n)
+		return -EAGAIN;
+	*n = *vma;
+	vma->vm_start = end;
+	n->vm_end = end;
+	vma->vm_offset += vma->vm_start - n->vm_start;
+	n->vm_flags = newflags;
+	if (n->vm_inode)
+		n->vm_inode->i_count++;
+	if (n->vm_ops && n->vm_ops->open)
+		n->vm_ops->open(n);
+	insert_vm_struct(current, n);
+	return 0;
+}
+
+static inline int mlock_fixup_end(struct vm_area_struct * vma,
+	unsigned long start, int newflags)
+{
+	struct vm_area_struct * n;
+
+	n = (struct vm_area_struct *) kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
+	if (!n)
+		return -EAGAIN;
+	*n = *vma;
+	vma->vm_end = start;
+	n->vm_start = start;
+	n->vm_offset += n->vm_start - vma->vm_start;
+	n->vm_flags = newflags;
+	if (n->vm_inode)
+		n->vm_inode->i_count++;
+	if (n->vm_ops && n->vm_ops->open)
+		n->vm_ops->open(n);
+	insert_vm_struct(current, n);
+	return 0;
+}
+
+static inline int mlock_fixup_middle(struct vm_area_struct * vma,
+	unsigned long start, unsigned long end, int newflags)
+{
+	struct vm_area_struct * left, * right;
+
+	left = (struct vm_area_struct *) kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
+	if (!left)
+		return -EAGAIN;
+	right = (struct vm_area_struct *) kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
+	if (!right) {
+		kfree(left);
+		return -EAGAIN;
+	}
+	*left = *vma;
+	*right = *vma;
+	left->vm_end = start;
+	vma->vm_start = start;
+	vma->vm_end = end;
+	right->vm_start = end;
+	vma->vm_offset += vma->vm_start - left->vm_start;
+	right->vm_offset += right->vm_start - left->vm_start;
+	vma->vm_flags = newflags;
+	if (vma->vm_inode)
+		vma->vm_inode->i_count += 2;
+	if (vma->vm_ops && vma->vm_ops->open) {
+		vma->vm_ops->open(left);
+		vma->vm_ops->open(right);
+	}
+	insert_vm_struct(current, left);
+	insert_vm_struct(current, right);
+	return 0;
+}
+
+static int mlock_fixup(struct vm_area_struct * vma, 
+	unsigned long start, unsigned long end, unsigned int newflags)
+{
+	int pages, retval;
+
+	if (newflags == vma->vm_flags)
+		return 0;
+
+	/* keep track of amount of locked VM */
+	pages = (end - start) >> PAGE_SHIFT;
+	if (!(newflags & VM_LOCKED))
+		pages = -pages;
+	vma->vm_mm->locked_vm += pages;
+
+	if (start == vma->vm_start) {
+		if (end == vma->vm_end)
+			retval = mlock_fixup_all(vma, newflags);
+		else
+			retval = mlock_fixup_start(vma, end, newflags);
+	} else {
+		if (end == vma->vm_end)
+			retval = mlock_fixup_end(vma, start, newflags);
+		else
+			retval = mlock_fixup_middle(vma, start, end, newflags);
+	}
+	if (!retval && (newflags & VM_LOCKED)) {
+		while (start < end) {
+			char c = get_user((char *) start);
+			__asm__ __volatile__("": :"r" (c));
+			start += PAGE_SIZE;
+		}
+	}
+	return retval;
+}
+
+static int do_mlock(unsigned long start, size_t len, int on)
+{
+	unsigned long nstart, end, tmp;
+	struct vm_area_struct * vma, * next;
+	int error;
+
+	if (!suser())
+		return -EPERM;
+	len = (len + ~PAGE_MASK) & PAGE_MASK;
+	end = start + len;
+	if (end < start)
+		return -EINVAL;
+	if (end == start)
+		return 0;
+	vma = find_vma(current, start);
+	if (!vma || vma->vm_start > start)
+		return -ENOMEM;
+
+	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;
+
+		if (vma->vm_end >= end) {
+			error = mlock_fixup(vma, nstart, end, newflags);
+			break;
+		}
+
+		tmp = vma->vm_end;
+		next = vma->vm_next;
+		error = mlock_fixup(vma, nstart, tmp, newflags);
+		if (error)
+			break;
+		nstart = tmp;
+		vma = next;
+		if (!vma || vma->vm_start != nstart) {
+			error = -ENOMEM;
+			break;
+		}
+	}
+	merge_segments(current, start, end);
+	return error;
+}
+
+asmlinkage int sys_mlock(unsigned long start, size_t len)
+{
+	unsigned long locked;
+	unsigned long lock_limit;
+
+	len = (len + (start & ~PAGE_MASK) + ~PAGE_MASK) & PAGE_MASK;
+	start &= PAGE_MASK;
+
+	locked = len >> PAGE_SHIFT;
+	locked += current->mm->locked_vm;
+
+	lock_limit = current->rlim[RLIMIT_MEMLOCK].rlim_cur;
+	lock_limit >>= PAGE_SHIFT;
+
+	/* check against resource limits */
+	if (locked > lock_limit)
+		return -ENOMEM;
+
+	/* we may lock at most half of physical memory... */
+	/* (this check is pretty bogus, but doesn't hurt) */
+	if (locked > MAP_NR(high_memory)/2)
+		return -ENOMEM;
+
+	return do_mlock(start, len, 1);
+}
+
+asmlinkage int sys_munlock(unsigned long start, size_t len)
+{
+	len = (len + (start & ~PAGE_MASK) + ~PAGE_MASK) & PAGE_MASK;
+	start &= PAGE_MASK;
+	return do_mlock(start, len, 0);
+}
+
+static int do_mlockall(int flags)
+{
+	int error;
+	unsigned int def_flags;
+	struct vm_area_struct * vma;
+
+	if (!suser())
+		return -EPERM;
+
+	def_flags = 0;
+	if (flags & MCL_FUTURE)
+		def_flags = VM_LOCKED;
+	current->mm->def_flags = def_flags;
+
+	error = 0;
+	for (vma = current->mm->mmap; vma ; vma = vma->vm_next) {
+		unsigned int newflags;
+
+		newflags = vma->vm_flags | VM_LOCKED;
+		if (!(flags & MCL_CURRENT))
+			newflags &= ~VM_LOCKED;
+		error = mlock_fixup(vma, vma->vm_start, vma->vm_end, newflags);
+		if (error)
+			break;
+	}
+	merge_segments(current, 0, TASK_SIZE);
+	return error;
+}
+
+asmlinkage int sys_mlockall(int flags)
+{
+	unsigned long lock_limit;
+
+	if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
+		return -EINVAL;
+
+	lock_limit = current->rlim[RLIMIT_MEMLOCK].rlim_cur;
+	lock_limit >>= PAGE_SHIFT;
+
+	if (current->mm->total_vm > lock_limit)
+		return -ENOMEM;
+
+	/* we may lock at most half of physical memory... */
+	/* (this check is pretty bogus, but doesn't hurt) */
+	if (current->mm->total_vm > MAP_NR(high_memory)/2)
+		return -ENOMEM;
+
+	return do_mlockall(flags);
+}
+
+asmlinkage int sys_munlockall(void)
+{
+	return do_mlockall(0);
+}