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Diffstat (limited to 'mm/shmem.c')
-rw-r--r--mm/shmem.c47
1 files changed, 38 insertions, 9 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index ea26d7a0342d..cddc72ac44d8 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -297,12 +297,14 @@ bool shmem_charge(struct inode *inode, long pages)
if (!shmem_inode_acct_block(inode, pages))
return false;
+ /* nrpages adjustment first, then shmem_recalc_inode() when balanced */
+ inode->i_mapping->nrpages += pages;
+
spin_lock_irqsave(&info->lock, flags);
info->alloced += pages;
inode->i_blocks += pages * BLOCKS_PER_PAGE;
shmem_recalc_inode(inode);
spin_unlock_irqrestore(&info->lock, flags);
- inode->i_mapping->nrpages += pages;
return true;
}
@@ -312,6 +314,8 @@ void shmem_uncharge(struct inode *inode, long pages)
struct shmem_inode_info *info = SHMEM_I(inode);
unsigned long flags;
+ /* nrpages adjustment done by __delete_from_page_cache() or caller */
+
spin_lock_irqsave(&info->lock, flags);
info->alloced -= pages;
inode->i_blocks -= pages * BLOCKS_PER_PAGE;
@@ -1509,11 +1513,13 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
{
struct page *oldpage, *newpage;
struct address_space *swap_mapping;
+ swp_entry_t entry;
pgoff_t swap_index;
int error;
oldpage = *pagep;
- swap_index = page_private(oldpage);
+ entry.val = page_private(oldpage);
+ swap_index = swp_offset(entry);
swap_mapping = page_mapping(oldpage);
/*
@@ -1532,7 +1538,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
__SetPageLocked(newpage);
__SetPageSwapBacked(newpage);
SetPageUptodate(newpage);
- set_page_private(newpage, swap_index);
+ set_page_private(newpage, entry.val);
SetPageSwapCache(newpage);
/*
@@ -2214,6 +2220,7 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
struct page *page;
pte_t _dst_pte, *dst_pte;
int ret;
+ pgoff_t offset, max_off;
ret = -ENOMEM;
if (!shmem_inode_acct_block(inode, 1))
@@ -2236,7 +2243,7 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
*pagep = page;
shmem_inode_unacct_blocks(inode, 1);
/* don't free the page */
- return -EFAULT;
+ return -ENOENT;
}
} else { /* mfill_zeropage_atomic */
clear_highpage(page);
@@ -2251,6 +2258,12 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
__SetPageSwapBacked(page);
__SetPageUptodate(page);
+ ret = -EFAULT;
+ offset = linear_page_index(dst_vma, dst_addr);
+ max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
+ if (unlikely(offset >= max_off))
+ goto out_release;
+
ret = mem_cgroup_try_charge_delay(page, dst_mm, gfp, &memcg, false);
if (ret)
goto out_release;
@@ -2265,9 +2278,25 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
_dst_pte = mk_pte(page, dst_vma->vm_page_prot);
if (dst_vma->vm_flags & VM_WRITE)
_dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte));
+ else {
+ /*
+ * We don't set the pte dirty if the vma has no
+ * VM_WRITE permission, so mark the page dirty or it
+ * could be freed from under us. We could do it
+ * unconditionally before unlock_page(), but doing it
+ * only if VM_WRITE is not set is faster.
+ */
+ set_page_dirty(page);
+ }
- ret = -EEXIST;
dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
+
+ ret = -EFAULT;
+ max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
+ if (unlikely(offset >= max_off))
+ goto out_release_uncharge_unlock;
+
+ ret = -EEXIST;
if (!pte_none(*dst_pte))
goto out_release_uncharge_unlock;
@@ -2285,13 +2314,15 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
/* No need to invalidate - it was non-present before */
update_mmu_cache(dst_vma, dst_addr, dst_pte);
- unlock_page(page);
pte_unmap_unlock(dst_pte, ptl);
+ unlock_page(page);
ret = 0;
out:
return ret;
out_release_uncharge_unlock:
pte_unmap_unlock(dst_pte, ptl);
+ ClearPageDirty(page);
+ delete_from_page_cache(page);
out_release_uncharge:
mem_cgroup_cancel_charge(page, memcg, false);
out_release:
@@ -2563,9 +2594,7 @@ static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence)
inode_lock(inode);
/* We're holding i_mutex so we can access i_size directly */
- if (offset < 0)
- offset = -EINVAL;
- else if (offset >= inode->i_size)
+ if (offset < 0 || offset >= inode->i_size)
offset = -ENXIO;
else {
start = offset >> PAGE_SHIFT;