xfs: simplify xfs_rtbuf_get calling conventions

Now that xfs_rtalloc_args holds references to the last-read bitmap and
summary blocks, we don't need to pass the buffer pointer out of
xfs_rtbuf_get.

Callers no longer have to xfs_trans_brelse on their own, though they are
required to call xfs_rtbuf_cache_relse before the xfs_rtalloc_args goes
out of scope.

While we're at it, create some trivial helpers so that we don't have to
remember if "0" means "bitmap" and "1" means "summary".
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_rtbitmap.h

@@ -295,7 +295,24 @@ typedef int (*xfs_rtalloc_query_range_fn)(
 void xfs_rtbuf_cache_relse(struct xfs_rtalloc_args *args);
 
 int xfs_rtbuf_get(struct xfs_rtalloc_args *args, xfs_fileoff_t block,
-		int issum, struct xfs_buf **bpp);
+		int issum);
+
+static inline int
+xfs_rtbitmap_read_buf(
+	struct xfs_rtalloc_args		*args,
+	xfs_fileoff_t			block)
+{
+	return xfs_rtbuf_get(args, block, 0);
+}
+
+static inline int
+xfs_rtsummary_read_buf(
+	struct xfs_rtalloc_args		*args,
+	xfs_fileoff_t			block)
+{
+	return xfs_rtbuf_get(args, block, 1);
+}
+
 int xfs_rtcheck_range(struct xfs_rtalloc_args *args, xfs_rtxnum_t start,
 		xfs_rtxlen_t len, int val, xfs_rtxnum_t *new, int *stat);
 int xfs_rtfind_back(struct xfs_rtalloc_args *args, xfs_rtxnum_t start,
@@ -348,7 +365,8 @@ unsigned long long xfs_rtsummary_wordcount(struct xfs_mount *mp,
 # define xfs_rtfree_blocks(t,rb,rl)			(-ENOSYS)
 # define xfs_rtalloc_query_range(m,t,l,h,f,p)		(-ENOSYS)
 # define xfs_rtalloc_query_all(m,t,f,p)			(-ENOSYS)
-# define xfs_rtbuf_get(m,t,b,i,p)			(-ENOSYS)
+# define xfs_rtbitmap_read_buf(a,b)			(-ENOSYS)
+# define xfs_rtsummary_read_buf(a,b)			(-ENOSYS)
 # define xfs_rtbuf_cache_relse(a)			(0)
 # define xfs_rtalloc_extent_is_free(m,t,s,l,i)		(-ENOSYS)
 static inline xfs_filblks_t

fs/xfs/scrub/rtsummary.c

@@ -193,7 +193,6 @@ xchk_rtsum_compare(
 		.tp		= sc->tp,
 	};
 	struct xfs_mount	*mp = sc->mp;
-	struct xfs_buf		*bp;
 	struct xfs_bmbt_irec	map;
 	xfs_fileoff_t		off;
 	xchk_rtsumoff_t		sumoff = 0;
@@ -221,7 +220,7 @@ xchk_rtsum_compare(
 		}
 
 		/* Read a block's worth of ondisk rtsummary file. */
-		error = xfs_rtbuf_get(&args, off, 1, &bp);
+		error = xfs_rtsummary_read_buf(&args, off);
 		if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, off, &error))
 			return error;
 
@@ -232,7 +231,7 @@ xchk_rtsum_compare(
 			return error;
 		}
 
-		ondisk_info = xfs_rsumblock_infoptr(bp, 0);
+		ondisk_info = xfs_rsumblock_infoptr(args.sumbp, 0);
 		if (memcmp(ondisk_info, sc->buf,
 					mp->m_blockwsize << XFS_WORDLOG) != 0)
 			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, off);