xfs: fix some minor sparse warnings

A couple of simple locking annotations and 0 vs NULL warnings.
Nothing that changes any code behaviour, just removes build noise.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_bmap.c

@@ -4450,7 +4450,7 @@ xfs_bmapi_write(
 {
 	struct xfs_mount	*mp = ip->i_mount;
 	struct xfs_ifork	*ifp;
-	struct xfs_bmalloca	bma = { 0 };	/* args for xfs_bmap_alloc */
+	struct xfs_bmalloca	bma = { NULL };	/* args for xfs_bmap_alloc */
 	xfs_fileoff_t		end;		/* end of mapped file region */
 	int			eof;		/* after the end of extents */
 	int			error;		/* error return */

fs/xfs/xfs_dquot_item.c

@@ -142,7 +142,8 @@ xfs_qm_dqunpin_wait(
 STATIC uint
 xfs_qm_dquot_logitem_push(
 	struct xfs_log_item	*lip,
-	struct list_head	*buffer_list)
+	struct list_head	*buffer_list) __releases(&lip->li_ailp->xa_lock)
+					      __acquires(&lip->li_ailp->xa_lock)
 {
 	struct xfs_dquot	*dqp = DQUOT_ITEM(lip)->qli_dquot;
 	struct xfs_buf		*bp = NULL;

fs/xfs/xfs_extent_busy.c

@@ -160,7 +160,8 @@ xfs_extent_busy_update_extent(
 	struct xfs_extent_busy	*busyp,
 	xfs_agblock_t		fbno,
 	xfs_extlen_t		flen,
-	bool			userdata)
+	bool			userdata) __releases(&pag->pagb_lock)
+					  __acquires(&pag->pagb_lock)
 {
 	xfs_agblock_t		fend = fbno + flen;
 	xfs_agblock_t		bbno = busyp->bno;

fs/xfs/xfs_ioctl.c

@@ -71,7 +71,7 @@ xfs_find_handle(
 	int			hsize;
 	xfs_handle_t		handle;
 	struct inode		*inode;
-	struct fd		f = {0};
+	struct fd		f = {NULL};
 	struct path		path;
 	int			error;
 	struct xfs_inode	*ip;

fs/xfs/xfs_itable.c

@@ -541,8 +541,9 @@ xfs_bulkstat_single(
 	 * at the expense of the error case.
 	 */
 
-	ino = (xfs_ino_t)*lastinop;
-	error = xfs_bulkstat_one(mp, ino, buffer, sizeof(xfs_bstat_t), 0, &res);
+	ino = *lastinop;
+	error = xfs_bulkstat_one(mp, ino, buffer, sizeof(xfs_bstat_t),
+				 NULL, &res);
 	if (error) {
 		/*
 		 * Special case way failed, do it the "long" way

fs/xfs/xfs_log.c

@@ -257,7 +257,8 @@ xlog_grant_head_wait(
 	struct xlog		*log,
 	struct xlog_grant_head	*head,
 	struct xlog_ticket	*tic,
-	int			need_bytes)
+	int			need_bytes) __releases(&head->lock)
+					    __acquires(&head->lock)
 {
 	list_add_tail(&tic->t_queue, &head->waiters);