xfs: remove the m_readio_* fields in struct xfs_mount

m_readio_blocks is entirely unused, and m_readio_blocks is only used in
xfs_stat_blksize in a max statements that is a no-op as it always has
the same value as m_writeio_log.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_iops.c

@@ -514,7 +514,7 @@ xfs_stat_blksize(
 		if (mp->m_swidth)
 			return mp->m_swidth << mp->m_sb.sb_blocklog;
 		if (mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)
-			return 1U << max(mp->m_readio_log, mp->m_writeio_log);
+			return 1U << mp->m_writeio_log;
 	}
 
 	return PAGE_SIZE;

fs/xfs/xfs_mount.c

@@ -437,25 +437,15 @@ xfs_set_rw_sizes(xfs_mount_t *mp)
 	xfs_sb_t	*sbp = &(mp->m_sb);
 	int		readio_log, writeio_log;
 
-	if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
-		readio_log = XFS_READIO_LOG_LARGE;
+	if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE))
 		writeio_log = XFS_WRITEIO_LOG_LARGE;
-	} else {
-		readio_log = mp->m_readio_log;
+	else
 		writeio_log = mp->m_writeio_log;
-	}
 
-	if (sbp->sb_blocklog > readio_log) {
-		mp->m_readio_log = sbp->sb_blocklog;
-	} else {
-		mp->m_readio_log = readio_log;
-	}
-	mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
-	if (sbp->sb_blocklog > writeio_log) {
+	if (sbp->sb_blocklog > writeio_log)
 		mp->m_writeio_log = sbp->sb_blocklog;
-	} else {
+	} else
 		mp->m_writeio_log = writeio_log;
-	}
 	mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
 }
 

fs/xfs/xfs_mount.h

@@ -98,8 +98,6 @@ typedef struct xfs_mount {
 	xfs_agnumber_t		m_agirotor;	/* last ag dir inode alloced */
 	spinlock_t		m_agirotor_lock;/* .. and lock protecting it */
 	xfs_agnumber_t		m_maxagi;	/* highest inode alloc group */
-	uint			m_readio_log;	/* min read size log bytes */
-	uint			m_readio_blocks; /* min read size blocks */
 	uint			m_writeio_log;	/* min write size log bytes */
 	uint			m_writeio_blocks; /* min write size blocks */
 	struct xfs_da_geometry	*m_dir_geo;	/* directory block geometry */
@@ -248,9 +246,8 @@ typedef struct xfs_mount {
 
 
 /*
- * Default minimum read and write sizes.
+ * Default write size.
  */
-#define XFS_READIO_LOG_LARGE	16
 #define XFS_WRITEIO_LOG_LARGE	16
 
 /*

fs/xfs/xfs_super.c

@@ -405,7 +405,6 @@ xfs_parseargs(
 		}
 
 		mp->m_flags |= XFS_MOUNT_DFLT_IOSIZE;
-		mp->m_readio_log = iosizelog;
 		mp->m_writeio_log = iosizelog;
 	}