1 files changed, 24 insertions, 69 deletions

diff --git a/fs/dax.c b/fs/dax.c
index 761495bf5eb9..993dc6fe0416 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -75,13 +75,13 @@ static long dax_map_atomic(struct block_device *bdev, struct blk_dax_ctl *dax)
 	struct request_queue *q = bdev->bd_queue;
 	long rc = -EIO;
 
-	dax->addr = (void __pmem *) ERR_PTR(-EIO);
+	dax->addr = ERR_PTR(-EIO);
 	if (blk_queue_enter(q, true) != 0)
 		return rc;
 
 	rc = bdev_direct_access(bdev, dax);
 	if (rc < 0) {
-		dax->addr = (void __pmem *) ERR_PTR(rc);
+		dax->addr = ERR_PTR(rc);
 		blk_queue_exit(q);
 		return rc;
 	}
@@ -147,12 +147,12 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
 		      struct buffer_head *bh)
 {
 	loff_t pos = start, max = start, bh_max = start;
-	bool hole = false, need_wmb = false;
+	bool hole = false;
 	struct block_device *bdev = NULL;
 	int rw = iov_iter_rw(iter), rc;
 	long map_len = 0;
 	struct blk_dax_ctl dax = {
-		.addr = (void __pmem *) ERR_PTR(-EIO),
+		.addr = ERR_PTR(-EIO),
 	};
 	unsigned blkbits = inode->i_blkbits;
 	sector_t file_blks = (i_size_read(inode) + (1 << blkbits) - 1)
@@ -208,12 +208,16 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
 				dax.addr += first;
 				size = map_len - first;
 			}
-			max = min(pos + size, end);
+			/*
+			 * pos + size is one past the last offset for IO,
+			 * so pos + size can overflow loff_t at extreme offsets.
+			 * Cast to u64 to catch this and get the true minimum.
+			 */
+			max = min_t(u64, pos + size, end);
 		}
 
 		if (iov_iter_rw(iter) == WRITE) {
 			len = copy_from_iter_pmem(dax.addr, max - pos, iter);
-			need_wmb = true;
 		} else if (!hole)
 			len = copy_to_iter((void __force *) dax.addr, max - pos,
 					iter);
@@ -230,8 +234,6 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
 			dax.addr += len;
 	}
 
-	if (need_wmb)
-		wmb_pmem();
 	dax_unmap_atomic(bdev, &dax);
 
 	return (pos == start) ? rc : pos - start;
@@ -783,7 +785,6 @@ int dax_writeback_mapping_range(struct address_space *mapping,
 				return ret;
 		}
 	}
-	wmb_pmem();
 	return 0;
 }
 EXPORT_SYMBOL_GPL(dax_writeback_mapping_range);
@@ -814,16 +815,16 @@ static int dax_insert_mapping(struct address_space *mapping,
 }
 
 /**
- * __dax_fault - handle a page fault on a DAX file
+ * dax_fault - handle a page fault on a DAX file
  * @vma: The virtual memory area where the fault occurred
  * @vmf: The description of the fault
  * @get_block: The filesystem method used to translate file offsets to blocks
  *
  * When a page fault occurs, filesystems may call this helper in their
- * fault handler for DAX files. __dax_fault() assumes the caller has done all
+ * fault handler for DAX files. dax_fault() assumes the caller has done all
  * the necessary locking for the page fault to proceed successfully.
  */
-int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
+int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 			get_block_t get_block)
 {
 	struct file *file = vma->vm_file;
@@ -908,33 +909,6 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 		return VM_FAULT_SIGBUS | major;
 	return VM_FAULT_NOPAGE | major;
 }
-EXPORT_SYMBOL(__dax_fault);
-
-/**
- * dax_fault - handle a page fault on a DAX file
- * @vma: The virtual memory area where the fault occurred
- * @vmf: The description of the fault
- * @get_block: The filesystem method used to translate file offsets to blocks
- *
- * When a page fault occurs, filesystems may call this helper in their
- * fault handler for DAX files.
- */
-int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
-	      get_block_t get_block)
-{
-	int result;
-	struct super_block *sb = file_inode(vma->vm_file)->i_sb;
-
-	if (vmf->flags & FAULT_FLAG_WRITE) {
-		sb_start_pagefault(sb);
-		file_update_time(vma->vm_file);
-	}
-	result = __dax_fault(vma, vmf, get_block);
-	if (vmf->flags & FAULT_FLAG_WRITE)
-		sb_end_pagefault(sb);
-
-	return result;
-}
 EXPORT_SYMBOL_GPL(dax_fault);
 
 #if defined(CONFIG_TRANSPARENT_HUGEPAGE)
@@ -962,7 +936,16 @@ static void __dax_dbg(struct buffer_head *bh, unsigned long address,
 
 #define dax_pmd_dbg(bh, address, reason)	__dax_dbg(bh, address, reason, "dax_pmd")
 
-int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
+/**
+ * dax_pmd_fault - handle a PMD fault on a DAX file
+ * @vma: The virtual memory area where the fault occurred
+ * @vmf: The description of the fault
+ * @get_block: The filesystem method used to translate file offsets to blocks
+ *
+ * When a page fault occurs, filesystems may call this helper in their
+ * pmd_fault handler for DAX files.
+ */
+int dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
 		pmd_t *pmd, unsigned int flags, get_block_t get_block)
 {
 	struct file *file = vma->vm_file;
@@ -1114,7 +1097,7 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
 		 *
 		 * The PMD path doesn't have an equivalent to
 		 * dax_pfn_mkwrite(), though, so for a read followed by a
-		 * write we traverse all the way through __dax_pmd_fault()
+		 * write we traverse all the way through dax_pmd_fault()
 		 * twice.  This means we can just skip inserting a radix tree
 		 * entry completely on the initial read and just wait until
 		 * the write to insert a dirty entry.
@@ -1143,33 +1126,6 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
 	result = VM_FAULT_FALLBACK;
 	goto out;
 }
-EXPORT_SYMBOL_GPL(__dax_pmd_fault);
-
-/**
- * dax_pmd_fault - handle a PMD fault on a DAX file
- * @vma: The virtual memory area where the fault occurred
- * @vmf: The description of the fault
- * @get_block: The filesystem method used to translate file offsets to blocks
- *
- * When a page fault occurs, filesystems may call this helper in their
- * pmd_fault handler for DAX files.
- */
-int dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
-			pmd_t *pmd, unsigned int flags, get_block_t get_block)
-{
-	int result;
-	struct super_block *sb = file_inode(vma->vm_file)->i_sb;
-
-	if (flags & FAULT_FLAG_WRITE) {
-		sb_start_pagefault(sb);
-		file_update_time(vma->vm_file);
-	}
-	result = __dax_pmd_fault(vma, address, pmd, flags, get_block);
-	if (flags & FAULT_FLAG_WRITE)
-		sb_end_pagefault(sb);
-
-	return result;
-}
 EXPORT_SYMBOL_GPL(dax_pmd_fault);
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
@@ -1227,7 +1183,6 @@ int __dax_zero_page_range(struct block_device *bdev, sector_t sector,
 		if (dax_map_atomic(bdev, &dax) < 0)
 			return PTR_ERR(dax.addr);
 		clear_pmem(dax.addr + offset, length);
-		wmb_pmem();
 		dax_unmap_atomic(bdev, &dax);
 	}
 	return 0;