mtd: do not use mtd->sync directly

This patch teaches 'mtd_sync()' to do nothing when the MTD driver does
not have the '->sync()' method, which allows us to remove all direct
'mtd->sync' accesses.

Signed-off-by: Artem Bityutskiy <[e-mail]>
Signed-off-by: David Woodhouse <[e-mail]>

drivers/mtd/ftl.c

···
 	    if (queued) {
 		pr_debug("ftl_cs: waiting for transfer "
 		      "unit to be prepared...\n");
-		if (part->mbd.mtd->sync)
-			mtd_sync(part->mbd.mtd);
+		mtd_sync(part->mbd.mtd);
 	    } else {
 		static int ne = 0;
 		if (++ne < 5)

drivers/mtd/mtdblock.c

···
 
 	if (!--mtdblk->count) {
 		/* It was the last usage. Free the cache */
-		if (mbd->mtd->sync)
-			mtd_sync(mbd->mtd);
+		mtd_sync(mbd->mtd);
 		vfree(mtdblk->cache_data);
 	}
 
···
 	mutex_lock(&mtdblk->cache_mutex);
 	write_cached_data(mtdblk);
 	mutex_unlock(&mtdblk->cache_mutex);
-
-	if (dev->mtd->sync)
-		mtd_sync(dev->mtd);
+	mtd_sync(dev->mtd);
 	return 0;
 }
 

drivers/mtd/mtdchar.c

···
 	pr_debug("MTD_close\n");
 
 	/* Only sync if opened RW */
-	if ((file->f_mode & FMODE_WRITE) && mtd->sync)
+	if ((file->f_mode & FMODE_WRITE))
 		mtd_sync(mtd);
 
 	iput(mfi->ino);

drivers/mtd/mtdswap.c

···
 {
 	struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
 
-	if (d->mtd->sync)
-		mtd_sync(d->mtd);
+	mtd_sync(d->mtd);
 	return 0;
 }
 

drivers/mtd/rfd_ftl.c

···
 	int rc;
 
 	/* we have a race if sync doesn't exist */
-	if (part->mbd.mtd->sync)
-		mtd_sync(part->mbd.mtd);
+	mtd_sync(part->mbd.mtd);
 
 	score = 0x7fffffff; /* MAX_INT */
 	best_block = -1;

drivers/mtd/ubi/kapi.c

···
 	if (!ubi)
 		return -ENODEV;
 
-	if (ubi->mtd->sync)
-		mtd_sync(ubi->mtd);
-
+	mtd_sync(ubi->mtd);
 	ubi_put_device(ubi);
 	return 0;
 }

fs/jffs2/super.c

···
 	jffs2_flash_cleanup(c);
 	kfree(c->inocache_list);
 	jffs2_clear_xattr_subsystem(c);
-	if (c->mtd->sync)
-		mtd_sync(c->mtd);
-
+	mtd_sync(c->mtd);
 	D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 }
 

fs/logfs/dev_mtd.c

···
 {
 	struct mtd_info *mtd = logfs_super(sb)->s_mtd;
 
-	if (mtd->sync)
-		mtd_sync(mtd);
+	mtd_sync(mtd);
 }
 
 static int logfs_mtd_readpage(void *_sb, struct page *page)

include/linux/mtd/mtd.h

···
 
 static inline void mtd_sync(struct mtd_info *mtd)
 {
-	mtd->sync(mtd);
+	if (mtd->sync)
+		mtd->sync(mtd);
 }
 
 /* Chip-supported device locking */