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-rw-r--r--fs/dax.c33
-rw-r--r--mm/memory.c11
2 files changed, 25 insertions, 19 deletions
diff --git a/fs/dax.c b/fs/dax.c
index c694117a7062..9593f4bee327 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -272,7 +272,6 @@ static int copy_user_bh(struct page *to, struct buffer_head *bh,
static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
struct vm_area_struct *vma, struct vm_fault *vmf)
{
- struct address_space *mapping = inode->i_mapping;
sector_t sector = bh->b_blocknr << (inode->i_blkbits - 9);
unsigned long vaddr = (unsigned long)vmf->virtual_address;
void *addr;
@@ -280,8 +279,6 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
pgoff_t size;
int error;
- i_mmap_lock_read(mapping);
-
/*
* Check truncate didn't happen while we were allocating a block.
* If it did, this block may or may not be still allocated to the
@@ -309,8 +306,6 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
error = vm_insert_mixed(vma, vaddr, pfn);
out:
- i_mmap_unlock_read(mapping);
-
return error;
}
@@ -372,15 +367,17 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
* from a read fault and we've raced with a truncate
*/
error = -EIO;
- goto unlock_page;
+ goto unlock;
}
+ } else {
+ i_mmap_lock_write(mapping);
}
error = get_block(inode, block, &bh, 0);
if (!error && (bh.b_size < PAGE_SIZE))
error = -EIO; /* fs corruption? */
if (error)
- goto unlock_page;
+ goto unlock;
if (!buffer_mapped(&bh) && !buffer_unwritten(&bh) && !vmf->cow_page) {
if (vmf->flags & FAULT_FLAG_WRITE) {
@@ -391,8 +388,9 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
if (!error && (bh.b_size < PAGE_SIZE))
error = -EIO;
if (error)
- goto unlock_page;
+ goto unlock;
} else {
+ i_mmap_unlock_write(mapping);
return dax_load_hole(mapping, page, vmf);
}
}
@@ -404,17 +402,15 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
else
clear_user_highpage(new_page, vaddr);
if (error)
- goto unlock_page;
+ goto unlock;
vmf->page = page;
if (!page) {
- i_mmap_lock_read(mapping);
/* Check we didn't race with truncate */
size = (i_size_read(inode) + PAGE_SIZE - 1) >>
PAGE_SHIFT;
if (vmf->pgoff >= size) {
- i_mmap_unlock_read(mapping);
error = -EIO;
- goto out;
+ goto unlock;
}
}
return VM_FAULT_LOCKED;
@@ -450,6 +446,8 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
WARN_ON_ONCE(!(vmf->flags & FAULT_FLAG_WRITE));
}
+ if (!page)
+ i_mmap_unlock_write(mapping);
out:
if (error == -ENOMEM)
return VM_FAULT_OOM | major;
@@ -458,11 +456,14 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
return VM_FAULT_SIGBUS | major;
return VM_FAULT_NOPAGE | major;
- unlock_page:
+ unlock:
if (page) {
unlock_page(page);
page_cache_release(page);
+ } else {
+ i_mmap_unlock_write(mapping);
}
+
goto out;
}
EXPORT_SYMBOL(__dax_fault);
@@ -540,10 +541,10 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
block = (sector_t)pgoff << (PAGE_SHIFT - blkbits);
bh.b_size = PMD_SIZE;
+ i_mmap_lock_write(mapping);
length = get_block(inode, block, &bh, write);
if (length)
return VM_FAULT_SIGBUS;
- i_mmap_lock_read(mapping);
/*
* If the filesystem isn't willing to tell us the length of a hole,
@@ -607,11 +608,11 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
}
out:
- i_mmap_unlock_read(mapping);
-
if (buffer_unwritten(&bh))
complete_unwritten(&bh, !(result & VM_FAULT_ERROR));
+ i_mmap_unlock_write(mapping);
+
return result;
fallback:
diff --git a/mm/memory.c b/mm/memory.c
index a3f9a8ccec0f..320c42e95e69 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2427,11 +2427,16 @@ void unmap_mapping_range(struct address_space *mapping,
details.last_index = ULONG_MAX;
- /* DAX uses i_mmap_lock to serialise file truncate vs page fault */
- i_mmap_lock_write(mapping);
+ /*
+ * DAX already holds i_mmap_lock to serialise file truncate vs
+ * page fault and page fault vs page fault.
+ */
+ if (!IS_DAX(mapping->host))
+ i_mmap_lock_write(mapping);
if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
unmap_mapping_range_tree(&mapping->i_mmap, &details);
- i_mmap_unlock_write(mapping);
+ if (!IS_DAX(mapping->host))
+ i_mmap_unlock_write(mapping);
}
EXPORT_SYMBOL(unmap_mapping_range);