xfs: convert buffer flags to unsigned.

5.18 w/ std=gnu11 compiled with gcc-5 wants flags stored in unsigned
fields to be unsigned. This manifests as a compiler error such as:

/kisskb/src/fs/xfs/./xfs_trace.h:432:2: note: in expansion of macro 'TP_printk'
  TP_printk("dev %d:%d daddr 0x%llx bbcount 0x%x hold %d pincount %d "
  ^
/kisskb/src/fs/xfs/./xfs_trace.h:440:5: note: in expansion of macro '__print_flags'
     __print_flags(__entry->flags, "|", XFS_BUF_FLAGS),
     ^
/kisskb/src/fs/xfs/xfs_buf.h:67:4: note: in expansion of macro 'XBF_UNMAPPED'
  { XBF_UNMAPPED,  "UNMAPPED" }
    ^
/kisskb/src/fs/xfs/./xfs_trace.h:440:40: note: in expansion of macro 'XFS_BUF_FLAGS'
     __print_flags(__entry->flags, "|", XFS_BUF_FLAGS),
                                        ^
/kisskb/src/fs/xfs/./xfs_trace.h: In function 'trace_raw_output_xfs_buf_flags_class':
/kisskb/src/fs/xfs/xfs_buf.h:46:23: error: initializer element is not constant
 #define XBF_UNMAPPED  (1 << 31)/* do not map the buffer */

as __print_flags assigns XFS_BUF_FLAGS to a structure that uses an
unsigned long for the flag. Since this results in the value of
XBF_UNMAPPED causing a signed integer overflow, the result is
technically undefined behavior, which gcc-5 does not accept as an
integer constant.

This is based on a patch from Arnd Bergman <arnd@arndb.de>.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/xfs_buf.c

@@ -406,7 +406,7 @@ xfs_buf_alloc_pages(
 STATIC int
 _xfs_buf_map_pages(
 	struct xfs_buf		*bp,
-	uint			flags)
+	xfs_buf_flags_t		flags)
 {
 	ASSERT(bp->b_flags & _XBF_PAGES);
 	if (bp->b_page_count == 1) {
@@ -868,7 +868,7 @@ xfs_buf_read_uncached(
 	struct xfs_buftarg	*target,
 	xfs_daddr_t		daddr,
 	size_t			numblks,
-	int			flags,
+	xfs_buf_flags_t		flags,
 	struct xfs_buf		**bpp,
 	const struct xfs_buf_ops *ops)
 {
@@ -903,7 +903,7 @@ int
 xfs_buf_get_uncached(
 	struct xfs_buftarg	*target,
 	size_t			numblks,
-	int			flags,
+	xfs_buf_flags_t		flags,
 	struct xfs_buf		**bpp)
 {
 	int			error;

fs/xfs/xfs_buf.h

@@ -22,28 +22,28 @@ struct xfs_buf;
 
 #define XFS_BUF_DADDR_NULL	((xfs_daddr_t) (-1LL))
 
-#define XBF_READ	 (1 << 0) /* buffer intended for reading from device */
-#define XBF_WRITE	 (1 << 1) /* buffer intended for writing to device */
-#define XBF_READ_AHEAD	 (1 << 2) /* asynchronous read-ahead */
-#define XBF_NO_IOACCT	 (1 << 3) /* bypass I/O accounting (non-LRU bufs) */
-#define XBF_ASYNC	 (1 << 4) /* initiator will not wait for completion */
-#define XBF_DONE	 (1 << 5) /* all pages in the buffer uptodate */
-#define XBF_STALE	 (1 << 6) /* buffer has been staled, do not find it */
-#define XBF_WRITE_FAIL	 (1 << 7) /* async writes have failed on this buffer */
+#define XBF_READ	 (1u << 0) /* buffer intended for reading from device */
+#define XBF_WRITE	 (1u << 1) /* buffer intended for writing to device */
+#define XBF_READ_AHEAD	 (1u << 2) /* asynchronous read-ahead */
+#define XBF_NO_IOACCT	 (1u << 3) /* bypass I/O accounting (non-LRU bufs) */
+#define XBF_ASYNC	 (1u << 4) /* initiator will not wait for completion */
+#define XBF_DONE	 (1u << 5) /* all pages in the buffer uptodate */
+#define XBF_STALE	 (1u << 6) /* buffer has been staled, do not find it */
+#define XBF_WRITE_FAIL	 (1u << 7) /* async writes have failed on this buffer */
 
 /* buffer type flags for write callbacks */
-#define _XBF_INODES	 (1 << 16)/* inode buffer */
-#define _XBF_DQUOTS	 (1 << 17)/* dquot buffer */
-#define _XBF_LOGRECOVERY	 (1 << 18)/* log recovery buffer */
+#define _XBF_INODES	 (1u << 16)/* inode buffer */
+#define _XBF_DQUOTS	 (1u << 17)/* dquot buffer */
+#define _XBF_LOGRECOVERY (1u << 18)/* log recovery buffer */
 
 /* flags used only internally */
-#define _XBF_PAGES	 (1 << 20)/* backed by refcounted pages */
-#define _XBF_KMEM	 (1 << 21)/* backed by heap memory */
-#define _XBF_DELWRI_Q	 (1 << 22)/* buffer on a delwri queue */
+#define _XBF_PAGES	 (1u << 20)/* backed by refcounted pages */
+#define _XBF_KMEM	 (1u << 21)/* backed by heap memory */
+#define _XBF_DELWRI_Q	 (1u << 22)/* buffer on a delwri queue */
 
 /* flags used only as arguments to access routines */
-#define XBF_TRYLOCK	 (1 << 30)/* lock requested, but do not wait */
-#define XBF_UNMAPPED	 (1 << 31)/* do not map the buffer */
+#define XBF_TRYLOCK	 (1u << 30)/* lock requested, but do not wait */
+#define XBF_UNMAPPED	 (1u << 31)/* do not map the buffer */
 
 typedef unsigned int xfs_buf_flags_t;
 
@@ -247,10 +247,10 @@ xfs_buf_readahead(
 	return xfs_buf_readahead_map(target, &map, 1, ops);
 }
 
-int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, int flags,
-		struct xfs_buf **bpp);
+int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
+		xfs_buf_flags_t flags, struct xfs_buf **bpp);
 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
-			  size_t numblks, int flags, struct xfs_buf **bpp,
+		size_t numblks, xfs_buf_flags_t flags, struct xfs_buf **bpp,
 		const struct xfs_buf_ops *ops);
 int _xfs_buf_read(struct xfs_buf *bp, xfs_buf_flags_t flags);
 void xfs_buf_hold(struct xfs_buf *bp);

fs/xfs/xfs_trans.h

@@ -175,7 +175,7 @@ xfs_trans_get_buf(
 	struct xfs_buftarg	*target,
 	xfs_daddr_t		blkno,
 	int			numblks,
-	uint			flags,
+	xfs_buf_flags_t		flags,
 	struct xfs_buf		**bpp)
 {
 	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);