#include <linux/mman.h>
#include <linux/pagemap.h>
#include <linux/syscalls.h>
+#include <linux/mempolicy.h>
#include <linux/hugetlb.h>
+#include <linux/sched.h>
+#include <linux/ksm.h>
+
+/*
+ * Any behaviour which results in changes to the vma->vm_flags needs to
+ * take mmap_sem for writing. Others, which simply traverse vmas, need
+ * to only take it for reading.
+ */
+static int madvise_need_mmap_write(int behavior)
+{
+ switch (behavior) {
+ case MADV_REMOVE:
+ case MADV_WILLNEED:
+ case MADV_DONTNEED:
+ return 0;
+ default:
+ /* be safe, default to 1. list exceptions explicitly */
+ return 1;
+ }
+}
/*
* 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 = 0;
+ pgoff_t pgoff;
+ unsigned long 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:
+ if (vma->vm_flags & VM_IO) {
+ error = -EINVAL;
+ goto out;
+ }
+ new_flags &= ~VM_DONTCOPY;
+ break;
+ case MADV_MERGEABLE:
+ case MADV_UNMERGEABLE:
+ error = ksm_madvise(vma, start, end, behavior, &new_flags);
+ if (error)
+ goto out;
+ 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);
goto out;
}
+success:
/*
* vm_flags is protected by the mmap_sem held in write mode.
*/
- 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;
- }
+ vma->vm_flags = new_flags;
out:
if (error == -ENOMEM)
* 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_mem) {
+ /* 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;
end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
- force_page_cache_readahead(file->f_mapping,
- file, start, max_sane_readahead(end - start));
+ force_page_cache_readahead(file->f_mapping, file, start, end - start);
return 0;
}
* Application no longer needs these pages. If the pages are dirty,
* it's OK to just throw them away. The app will be more careful about
* data it wants to keep. Be sure to free swap resources too. The
- * zap_page_range call sets things up for refill_inactive to actually free
+ * zap_page_range call sets things up for shrink_active_list to actually free
* these pages later if no one else has touched them in the meantime,
* although we could add these pages to a global reuse list for
- * refill_inactive to pick up before reclaiming other pages.
+ * shrink_active_list to pick up before reclaiming other pages.
*
* NB: This interface discards data rather than pushes it out to swap,
* as some implementations do. This has performance implications for
* 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)
{
- if ((vma->vm_flags & VM_LOCKED) || is_vm_hugetlb_page(vma))
+ *prev = vma;
+ if (vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP))
return -EINVAL;
if (unlikely(vma->vm_flags & VM_NONLINEAR)) {
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)
+{
+ 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_read(¤t->mm->mmap_sem);
+ error = vmtruncate_range(mapping->host, offset, endoff);
+ down_read(¤t->mm->mmap_sem);
+ return error;
+}
+
+#ifdef CONFIG_MEMORY_FAILURE
+/*
+ * Error injection support for memory error handling.
+ */
+static int madvise_hwpoison(unsigned long start, unsigned long end)
{
- long error = -EBADF;
+ int ret = 0;
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ for (; start < end; start += PAGE_SIZE) {
+ struct page *p;
+ int ret = get_user_pages(current, current->mm, start, 1,
+ 0, 0, &p, NULL);
+ if (ret != 1)
+ return ret;
+ printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n",
+ page_to_pfn(p), start);
+ /* Ignore return value for now */
+ __memory_failure(page_to_pfn(p), 0, 1);
+ put_page(p);
+ }
+ return ret;
+}
+#endif
+
+static long
+madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
+ unsigned long start, unsigned long end, int behavior)
+{
switch (behavior) {
+ case MADV_REMOVE:
+ return madvise_remove(vma, prev, start, end);
+ case MADV_WILLNEED:
+ return madvise_willneed(vma, prev, start, end);
+ case MADV_DONTNEED:
+ return madvise_dontneed(vma, prev, start, end);
+ default:
+ return madvise_behavior(vma, prev, start, end, behavior);
+ }
+}
+
+static int
+madvise_behavior_valid(int behavior)
+{
+ switch (behavior) {
+ case MADV_DOFORK:
+ case MADV_DONTFORK:
case MADV_NORMAL:
case MADV_SEQUENTIAL:
case MADV_RANDOM:
- error = madvise_behavior(vma, start, end, behavior);
- break;
-
+ case MADV_REMOVE:
case MADV_WILLNEED:
- error = madvise_willneed(vma, start, end);
- break;
-
case MADV_DONTNEED:
- error = madvise_dontneed(vma, start, end);
- break;
+#ifdef CONFIG_KSM
+ case MADV_MERGEABLE:
+ case MADV_UNMERGEABLE:
+#endif
+ return 1;
default:
- error = -EINVAL;
- break;
+ return 0;
}
-
- 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.
+ * MADV_DONTFORK - omit this area from child's address space when forking:
+ * typically, to avoid COWing pages pinned by get_user_pages().
+ * MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
+ * MADV_MERGEABLE - the application recommends that KSM try to merge pages in
+ * this area with pages of identical content from other such areas.
+ * MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others.
*
* 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_in, int behavior)
+SYSCALL_DEFINE3(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;
+ int write;
size_t len;
- down_write(¤t->mm->mmap_sem);
+#ifdef CONFIG_MEMORY_FAILURE
+ if (behavior == MADV_HWPOISON)
+ return madvise_hwpoison(start, start+len_in);
+#endif
+ if (!madvise_behavior_valid(behavior))
+ return error;
+
+ write = madvise_need_mmap_write(behavior);
+ if (write)
+ down_write(¤t->mm->mmap_sem);
+ else
+ down_read(¤t->mm->mmap_sem);
if (start & ~PAGE_MASK)
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);
+ if (write)
+ up_write(¤t->mm->mmap_sem);
+ else
+ up_read(¤t->mm->mmap_sem);
+
return error;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff