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Diffstat (limited to 'mm/mlock.c')
-rw-r--r--mm/mlock.c100
1 files changed, 68 insertions, 32 deletions
diff --git a/mm/mlock.c b/mm/mlock.c
index 25936680064f..339d9e0949b6 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -422,7 +422,7 @@ static unsigned long __munlock_pagevec_fill(struct pagevec *pvec,
void munlock_vma_pages_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
- vma->vm_flags &= ~VM_LOCKED;
+ vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
while (start < end) {
struct page *page = NULL;
@@ -506,7 +506,8 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) ||
is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm))
- goto out; /* don't set VM_LOCKED, don't count */
+ /* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */
+ goto out;
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
*prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
@@ -554,13 +555,14 @@ out:
return ret;
}
-static int do_mlock(unsigned long start, size_t len, int on)
+static int apply_vma_lock_flags(unsigned long start, size_t len,
+ vm_flags_t flags)
{
unsigned long nstart, end, tmp;
struct vm_area_struct * vma, * prev;
int error;
- VM_BUG_ON(start & ~PAGE_MASK);
+ VM_BUG_ON(offset_in_page(start));
VM_BUG_ON(len != PAGE_ALIGN(len));
end = start + len;
if (end < start)
@@ -576,14 +578,11 @@ static int do_mlock(unsigned long start, size_t len, int on)
prev = vma;
for (nstart = start ; ; ) {
- vm_flags_t newflags;
+ vm_flags_t newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
- /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
-
- newflags = vma->vm_flags & ~VM_LOCKED;
- if (on)
- newflags |= VM_LOCKED;
+ newflags |= flags;
+ /* Here we know that vma->vm_start <= nstart < vma->vm_end. */
tmp = vma->vm_end;
if (tmp > end)
tmp = end;
@@ -605,7 +604,7 @@ static int do_mlock(unsigned long start, size_t len, int on)
return error;
}
-SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
+static int do_mlock(unsigned long start, size_t len, vm_flags_t flags)
{
unsigned long locked;
unsigned long lock_limit;
@@ -616,7 +615,7 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
lru_add_drain_all(); /* flush pagevec */
- len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
+ len = PAGE_ALIGN(len + (offset_in_page(start)));
start &= PAGE_MASK;
lock_limit = rlimit(RLIMIT_MEMLOCK);
@@ -629,7 +628,7 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
/* check against resource limits */
if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
- error = do_mlock(start, len, 1);
+ error = apply_vma_lock_flags(start, len, flags);
up_write(&current->mm->mmap_sem);
if (error)
@@ -641,37 +640,75 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
return 0;
}
+SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
+{
+ return do_mlock(start, len, VM_LOCKED);
+}
+
+SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags)
+{
+ vm_flags_t vm_flags = VM_LOCKED;
+
+ if (flags & ~MLOCK_ONFAULT)
+ return -EINVAL;
+
+ if (flags & MLOCK_ONFAULT)
+ vm_flags |= VM_LOCKONFAULT;
+
+ return do_mlock(start, len, vm_flags);
+}
+
SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
{
int ret;
- len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
+ len = PAGE_ALIGN(len + (offset_in_page(start)));
start &= PAGE_MASK;
down_write(&current->mm->mmap_sem);
- ret = do_mlock(start, len, 0);
+ ret = apply_vma_lock_flags(start, len, 0);
up_write(&current->mm->mmap_sem);
return ret;
}
-static int do_mlockall(int flags)
+/*
+ * Take the MCL_* flags passed into mlockall (or 0 if called from munlockall)
+ * and translate into the appropriate modifications to mm->def_flags and/or the
+ * flags for all current VMAs.
+ *
+ * There are a couple of subtleties with this. If mlockall() is called multiple
+ * times with different flags, the values do not necessarily stack. If mlockall
+ * is called once including the MCL_FUTURE flag and then a second time without
+ * it, VM_LOCKED and VM_LOCKONFAULT will be cleared from mm->def_flags.
+ */
+static int apply_mlockall_flags(int flags)
{
struct vm_area_struct * vma, * prev = NULL;
+ vm_flags_t to_add = 0;
- if (flags & MCL_FUTURE)
+ current->mm->def_flags &= VM_LOCKED_CLEAR_MASK;
+ if (flags & MCL_FUTURE) {
current->mm->def_flags |= VM_LOCKED;
- else
- current->mm->def_flags &= ~VM_LOCKED;
- if (flags == MCL_FUTURE)
- goto out;
+
+ if (flags & MCL_ONFAULT)
+ current->mm->def_flags |= VM_LOCKONFAULT;
+
+ if (!(flags & MCL_CURRENT))
+ goto out;
+ }
+
+ if (flags & MCL_CURRENT) {
+ to_add |= VM_LOCKED;
+ if (flags & MCL_ONFAULT)
+ to_add |= VM_LOCKONFAULT;
+ }
for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
vm_flags_t newflags;
- newflags = vma->vm_flags & ~VM_LOCKED;
- if (flags & MCL_CURRENT)
- newflags |= VM_LOCKED;
+ newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
+ newflags |= to_add;
/* Ignore errors */
mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
@@ -684,14 +721,13 @@ out:
SYSCALL_DEFINE1(mlockall, int, flags)
{
unsigned long lock_limit;
- int ret = -EINVAL;
+ int ret;
- if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
- goto out;
+ if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT)))
+ return -EINVAL;
- ret = -EPERM;
if (!can_do_mlock())
- goto out;
+ return -EPERM;
if (flags & MCL_CURRENT)
lru_add_drain_all(); /* flush pagevec */
@@ -704,11 +740,11 @@ SYSCALL_DEFINE1(mlockall, int, flags)
if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
capable(CAP_IPC_LOCK))
- ret = do_mlockall(flags);
+ ret = apply_mlockall_flags(flags);
up_write(&current->mm->mmap_sem);
if (!ret && (flags & MCL_CURRENT))
mm_populate(0, TASK_SIZE);
-out:
+
return ret;
}
@@ -717,7 +753,7 @@ SYSCALL_DEFINE0(munlockall)
int ret;
down_write(&current->mm->mmap_sem);
- ret = do_mlockall(0);
+ ret = apply_mlockall_flags(0);
up_write(&current->mm->mmap_sem);
return ret;
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-17 13:26:08 +0300