#include <linux/mman.h>
#include <linux/pagemap.h>
-
+#include <linux/syscalls.h>
+#include <linux/mempolicy.h>
+#include <linux/hugetlb.h>
/*
* We can potentially split a vm area into separate
* areas, each area with its own behavior.
*/
-static long madvise_behavior(struct vm_area_struct * vma, unsigned long start,
- unsigned long end, int behavior)
+static long madvise_behavior(struct vm_area_struct * vma,
+ struct vm_area_struct **prev,
+ unsigned long start, unsigned long end, int behavior)
{
struct mm_struct * mm = vma->vm_mm;
- int error;
+ int error = 0;
+ pgoff_t pgoff;
+ int new_flags = vma->vm_flags;
+
+ switch (behavior) {
+ case MADV_NORMAL:
+ new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ;
+ break;
+ case MADV_SEQUENTIAL:
+ new_flags = (new_flags & ~VM_RAND_READ) | VM_SEQ_READ;
+ break;
+ case MADV_RANDOM:
+ new_flags = (new_flags & ~VM_SEQ_READ) | VM_RAND_READ;
+ break;
+ case MADV_DONTFORK:
+ new_flags |= VM_DONTCOPY;
+ break;
+ case MADV_DOFORK:
+ new_flags &= ~VM_DONTCOPY;
+ break;
+ }
+
+ if (new_flags == vma->vm_flags) {
+ *prev = vma;
+ goto out;
+ }
+
+ pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
+ *prev = vma_merge(mm, *prev, start, end, new_flags, vma->anon_vma,
+ vma->vm_file, pgoff, vma_policy(vma));
+ if (*prev) {
+ vma = *prev;
+ goto success;
+ }
+
+ *prev = vma;
if (start != vma->vm_start) {
error = split_vma(mm, vma, start, 1);
if (error)
- return -EAGAIN;
+ goto out;
}
if (end != vma->vm_end) {
error = split_vma(mm, vma, end, 0);
if (error)
- return -EAGAIN;
+ goto out;
}
- spin_lock(&mm->page_table_lock);
- VM_ClearReadHint(vma);
-
- switch (behavior) {
- case MADV_SEQUENTIAL:
- vma->vm_flags |= VM_SEQ_READ;
- break;
- case MADV_RANDOM:
- vma->vm_flags |= VM_RAND_READ;
- break;
- default:
- break;
- }
- spin_unlock(&mm->page_table_lock);
+success:
+ /*
+ * vm_flags is protected by the mmap_sem held in write mode.
+ */
+ vma->vm_flags = new_flags;
- return 0;
+out:
+ if (error == -ENOMEM)
+ error = -EAGAIN;
+ return error;
}
/*
* Schedule all required I/O operations. Do not wait for completion.
*/
static long madvise_willneed(struct vm_area_struct * vma,
+ struct vm_area_struct ** prev,
unsigned long start, unsigned long end)
{
struct file *file = vma->vm_file;
if (!file)
return -EBADF;
+ if (file->f_mapping->a_ops->get_xip_page) {
+ /* no bad return value, but ignore advice */
+ return 0;
+ }
+
+ *prev = vma;
start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
if (end > vma->vm_end)
end = vma->vm_end;
* dirty pages is already available as msync(MS_INVALIDATE).
*/
static long madvise_dontneed(struct vm_area_struct * vma,
+ struct vm_area_struct ** prev,
unsigned long start, unsigned long end)
{
- struct zap_details details;
-
- if (vma->vm_flags & VM_LOCKED)
+ *prev = vma;
+ if (vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP))
return -EINVAL;
if (unlikely(vma->vm_flags & VM_NONLINEAR)) {
- details.check_mapping = NULL;
- details.nonlinear_vma = vma;
- details.first_index = 0;
- details.last_index = ULONG_MAX;
+ struct zap_details details = {
+ .nonlinear_vma = vma,
+ .last_index = ULONG_MAX,
+ };
zap_page_range(vma, start, end - start, &details);
} else
zap_page_range(vma, start, end - start, NULL);
return 0;
}
-static long madvise_vma(struct vm_area_struct * vma, unsigned long start,
- unsigned long end, int behavior)
+/*
+ * Application wants to free up the pages and associated backing store.
+ * This is effectively punching a hole into the middle of a file.
+ *
+ * NOTE: Currently, only shmfs/tmpfs is supported for this operation.
+ * Other filesystems return -ENOSYS.
+ */
+static long madvise_remove(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
+ unsigned long start, unsigned long end)
{
- long error = -EBADF;
+ struct address_space *mapping;
+ loff_t offset, endoff;
+ int error;
+
+ *prev = NULL; /* tell sys_madvise we drop mmap_sem */
+
+ if (vma->vm_flags & (VM_LOCKED|VM_NONLINEAR|VM_HUGETLB))
+ return -EINVAL;
+
+ if (!vma->vm_file || !vma->vm_file->f_mapping
+ || !vma->vm_file->f_mapping->host) {
+ return -EINVAL;
+ }
+
+ if ((vma->vm_flags & (VM_SHARED|VM_WRITE)) != (VM_SHARED|VM_WRITE))
+ return -EACCES;
+
+ mapping = vma->vm_file->f_mapping;
+
+ offset = (loff_t)(start - vma->vm_start)
+ + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+ endoff = (loff_t)(end - vma->vm_start - 1)
+ + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+
+ /* vmtruncate_range needs to take i_mutex and i_alloc_sem */
+ up_write(¤t->mm->mmap_sem);
+ error = vmtruncate_range(mapping->host, offset, endoff);
+ down_write(¤t->mm->mmap_sem);
+ return error;
+}
+
+static long
+madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
+ unsigned long start, unsigned long end, int behavior)
+{
+ long error;
switch (behavior) {
+ case MADV_DOFORK:
+ if (vma->vm_flags & VM_IO) {
+ error = -EINVAL;
+ break;
+ }
+ case MADV_DONTFORK:
case MADV_NORMAL:
case MADV_SEQUENTIAL:
case MADV_RANDOM:
- error = madvise_behavior(vma, start, end, behavior);
+ error = madvise_behavior(vma, prev, start, end, behavior);
+ break;
+ case MADV_REMOVE:
+ error = madvise_remove(vma, prev, start, end);
break;
case MADV_WILLNEED:
- error = madvise_willneed(vma, start, end);
+ error = madvise_willneed(vma, prev, start, end);
break;
case MADV_DONTNEED:
- error = madvise_dontneed(vma, start, end);
+ error = madvise_dontneed(vma, prev, start, end);
break;
default:
error = -EINVAL;
break;
}
-
return error;
}
* some pages ahead.
* MADV_DONTNEED - the application is finished with the given range,
* so the kernel can free resources associated with it.
+ * MADV_REMOVE - the application wants to free up the given range of
+ * pages and associated backing store.
*
* return values:
* zero - success
* -EBADF - map exists, but area maps something that isn't a file.
* -EAGAIN - a kernel resource was temporarily unavailable.
*/
-asmlinkage long sys_madvise(unsigned long start, size_t len, int behavior)
+asmlinkage long sys_madvise(unsigned long start, size_t len_in, int behavior)
{
- unsigned long end;
- struct vm_area_struct * vma;
+ unsigned long end, tmp;
+ struct vm_area_struct * vma, *prev;
int unmapped_error = 0;
int error = -EINVAL;
+ size_t len;
down_write(¤t->mm->mmap_sem);
if (start & ~PAGE_MASK)
goto out;
- len = (len + ~PAGE_MASK) & PAGE_MASK;
+ len = (len_in + ~PAGE_MASK) & PAGE_MASK;
+
+ /* Check to see whether len was rounded up from small -ve to zero */
+ if (len_in && !len)
+ goto out;
+
end = start + len;
if (end < start)
goto out;
/*
* If the interval [start,end) covers some unmapped address
* ranges, just ignore them, but return -ENOMEM at the end.
+ * - different from the way of handling in mlock etc.
*/
- vma = find_vma(current->mm, start);
+ vma = find_vma_prev(current->mm, start, &prev);
+ if (vma && start > vma->vm_start)
+ prev = vma;
+
for (;;) {
/* Still start < end. */
error = -ENOMEM;
if (!vma)
goto out;
- /* Here start < vma->vm_end. */
+ /* Here start < (end|vma->vm_end). */
if (start < vma->vm_start) {
unmapped_error = -ENOMEM;
start = vma->vm_start;
+ if (start >= end)
+ goto out;
}
- /* Here vma->vm_start <= start < vma->vm_end. */
- if (end <= vma->vm_end) {
- if (start < end) {
- error = madvise_vma(vma, start, end,
- behavior);
- if (error)
- goto out;
- }
- error = unmapped_error;
- goto out;
- }
+ /* Here vma->vm_start <= start < (end|vma->vm_end) */
+ tmp = vma->vm_end;
+ if (end < tmp)
+ tmp = end;
- /* Here vma->vm_start <= start < vma->vm_end < end. */
- error = madvise_vma(vma, start, vma->vm_end, behavior);
+ /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
+ error = madvise_vma(vma, &prev, start, tmp, behavior);
if (error)
goto out;
- start = vma->vm_end;
- vma = vma->vm_next;
+ start = tmp;
+ if (prev && start < prev->vm_end)
+ start = prev->vm_end;
+ error = unmapped_error;
+ if (start >= end)
+ goto out;
+ if (prev)
+ vma = prev->vm_next;
+ else /* madvise_remove dropped mmap_sem */
+ vma = find_vma(current->mm, start);
}
-
out:
up_write(¤t->mm->mmap_sem);
return error;
git://git.onelab.eu / linux-2.6.git / blobdiff