mm: remove enum page_entry_size

Remove the unnecessary encoding of page order into an enum and pass the
page order directly.  That lets us get rid of pe_order().

The switch constructs have to be changed to if/else constructs to prevent
GCC from warning on builds with 3-level page tables where PMD_ORDER and
PUD_ORDER have the same value.

If you are looking at this commit because your driver stopped compiling,
look at the previous commit as well and audit your driver to be sure it
doesn't depend on mmap_lock being held in its ->huge_fault method.

[willy@infradead.org: use "order %u" to match the (non dev_t) style]
  Link: https://lkml.kernel.org/r/ZOUYekbtTv+n8hYf@casper.infradead.org
Link: https://lkml.kernel.org/r/20230818202335.2739663-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 18 insertions, 26 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 4f502219ae4f..203700278ddb 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1287,11 +1287,11 @@ xfs_file_llseek(
 static inline vm_fault_t
 xfs_dax_fault(
 	struct vm_fault		*vmf,
-	enum page_entry_size	pe_size,
+	unsigned int		order,
 	bool			write_fault,
 	pfn_t			*pfn)
 {
-	return dax_iomap_fault(vmf, pe_size, pfn, NULL,
+	return dax_iomap_fault(vmf, order, pfn, NULL,
 			(write_fault && !vmf->cow_page) ?
 				&xfs_dax_write_iomap_ops :
 				&xfs_read_iomap_ops);
@@ -1300,7 +1300,7 @@ xfs_dax_fault(
 static inline vm_fault_t
 xfs_dax_fault(
 	struct vm_fault		*vmf,
-	enum page_entry_size	pe_size,
+	unsigned int		order,
 	bool			write_fault,
 	pfn_t			*pfn)
 {
@@ -1322,14 +1322,14 @@ xfs_dax_fault(
 static vm_fault_t
 __xfs_filemap_fault(
 	struct vm_fault		*vmf,
-	enum page_entry_size	pe_size,
+	unsigned int		order,
 	bool			write_fault)
 {
 	struct inode		*inode = file_inode(vmf->vma->vm_file);
 	struct xfs_inode	*ip = XFS_I(inode);
 	vm_fault_t		ret;
 
-	trace_xfs_filemap_fault(ip, pe_size, write_fault);
+	trace_xfs_filemap_fault(ip, order, write_fault);
 
 	if (write_fault) {
 		sb_start_pagefault(inode->i_sb);
@@ -1340,9 +1340,9 @@ __xfs_filemap_fault(
 		pfn_t pfn;
 
 		xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
-		ret = xfs_dax_fault(vmf, pe_size, write_fault, &pfn);
+		ret = xfs_dax_fault(vmf, order, write_fault, &pfn);
 		if (ret & VM_FAULT_NEEDDSYNC)
-			ret = dax_finish_sync_fault(vmf, pe_size, pfn);
+			ret = dax_finish_sync_fault(vmf, order, pfn);
 		xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
 	} else {
 		if (write_fault) {
@@ -1373,7 +1373,7 @@ xfs_filemap_fault(
 	struct vm_fault		*vmf)
 {
 	/* DAX can shortcut the normal fault path on write faults! */
-	return __xfs_filemap_fault(vmf, PE_SIZE_PTE,
+	return __xfs_filemap_fault(vmf, 0,
 			IS_DAX(file_inode(vmf->vma->vm_file)) &&
 			xfs_is_write_fault(vmf));
 }
@@ -1381,13 +1381,13 @@ xfs_filemap_fault(
 static vm_fault_t
 xfs_filemap_huge_fault(
 	struct vm_fault		*vmf,
-	enum page_entry_size	pe_size)
+	unsigned int		order)
 {
 	if (!IS_DAX(file_inode(vmf->vma->vm_file)))
 		return VM_FAULT_FALLBACK;
 
 	/* DAX can shortcut the normal fault path on write faults! */
-	return __xfs_filemap_fault(vmf, pe_size,
+	return __xfs_filemap_fault(vmf, order,
 			xfs_is_write_fault(vmf));
 }
 
@@ -1395,7 +1395,7 @@ static vm_fault_t
 xfs_filemap_page_mkwrite(
 	struct vm_fault		*vmf)
 {
-	return __xfs_filemap_fault(vmf, PE_SIZE_PTE, true);
+	return __xfs_filemap_fault(vmf, 0, true);
 }
 
 /*
@@ -1408,7 +1408,7 @@ xfs_filemap_pfn_mkwrite(
 	struct vm_fault		*vmf)
 {
 
-	return __xfs_filemap_fault(vmf, PE_SIZE_PTE, true);
+	return __xfs_filemap_fault(vmf, 0, true);
 }
 
 static const struct vm_operations_struct xfs_file_vm_ops = {
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index f3cc204bb4bf..fd789e00dfd6 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -802,36 +802,28 @@ DEFINE_INODE_EVENT(xfs_inode_inactivating);
  * ring buffer.  Somehow this was only worth mentioning in the ftrace sample
  * code.
  */
-TRACE_DEFINE_ENUM(PE_SIZE_PTE);
-TRACE_DEFINE_ENUM(PE_SIZE_PMD);
-TRACE_DEFINE_ENUM(PE_SIZE_PUD);
-
 TRACE_DEFINE_ENUM(XFS_REFC_DOMAIN_SHARED);
 TRACE_DEFINE_ENUM(XFS_REFC_DOMAIN_COW);
 
 TRACE_EVENT(xfs_filemap_fault,
-	TP_PROTO(struct xfs_inode *ip, enum page_entry_size pe_size,
-		 bool write_fault),
-	TP_ARGS(ip, pe_size, write_fault),
+	TP_PROTO(struct xfs_inode *ip, unsigned int order, bool write_fault),
+	TP_ARGS(ip, order, write_fault),
 	TP_STRUCT__entry(
 		__field(dev_t, dev)
 		__field(xfs_ino_t, ino)
-		__field(enum page_entry_size, pe_size)
+		__field(unsigned int, order)
 		__field(bool, write_fault)
 	),
 	TP_fast_assign(
 		__entry->dev = VFS_I(ip)->i_sb->s_dev;
 		__entry->ino = ip->i_ino;
-		__entry->pe_size = pe_size;
+		__entry->order = order;
 		__entry->write_fault = write_fault;
 	),
-	TP_printk("dev %d:%d ino 0x%llx %s write_fault %d",
+	TP_printk("dev %d:%d ino 0x%llx order %u write_fault %d",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->ino,
-		  __print_symbolic(__entry->pe_size,
-			{ PE_SIZE_PTE,	"PTE" },
-			{ PE_SIZE_PMD,	"PMD" },
-			{ PE_SIZE_PUD,	"PUD" }),
+		  __entry->order,
 		  __entry->write_fault)
 )