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-rw-r--r--mm/shmem.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 96fa79fb6ad3..5808fadd3944 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -83,6 +83,7 @@ enum sgp_type {
SGP_READ, /* don't exceed i_size, don't allocate page */
SGP_CACHE, /* don't exceed i_size, may allocate page */
SGP_WRITE, /* may exceed i_size, may allocate page */
+ SGP_NOPAGE, /* same as SGP_CACHE, return with page locked */
};
static int shmem_getpage(struct inode *inode, unsigned long idx,
@@ -1289,8 +1290,10 @@ repeat:
}
done:
if (*pagep != filepage) {
- unlock_page(filepage);
*pagep = filepage;
+ if (sgp != SGP_NOPAGE)
+ unlock_page(filepage);
+
}
return 0;
@@ -1310,13 +1313,15 @@ static struct page *shmem_nopage(struct vm_area_struct *vma,
unsigned long idx;
int error;
+ BUG_ON(!(vma->vm_flags & VM_CAN_INVALIDATE));
+
idx = (address - vma->vm_start) >> PAGE_SHIFT;
idx += vma->vm_pgoff;
idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode))
return NOPAGE_SIGBUS;
- error = shmem_getpage(inode, idx, &page, SGP_CACHE, type);
+ error = shmem_getpage(inode, idx, &page, SGP_NOPAGE, type);
if (error)
return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS;
@@ -1414,6 +1419,7 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
{
file_accessed(file);
vma->vm_ops = &shmem_vm_ops;
+ vma->vm_flags |= VM_CAN_INVALIDATE;
return 0;
}
@@ -2596,5 +2602,6 @@ int shmem_zero_setup(struct vm_area_struct *vma)
fput(vma->vm_file);
vma->vm_file = file;
vma->vm_ops = &shmem_vm_ops;
+ vma->vm_flags |= VM_CAN_INVALIDATE;
return 0;
}