mtd: nand: Drop mtd.owner requirement in nand_scan

commit 20c07a5bf094198ff2382aa5e7c930b3c9807792 upstream.

Since commit 807f16d4db95 ("mtd: core: set some defaults
when dev.parent is set"), it's now legal for drivers
to call nand_scan and nand_scan_ident without setting
mtd.owner.

Drop the check and while at it remove the BUG() abuse.

Fixes: 807f16d4db95 ("mtd: core: set some defaults when dev.parent is set")
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[Brian: editorial note - while commit 807f16d4db95 wasn't explicitly
    broken, some follow-up commits in the v4.4 release broke a few
    drivers, since they would hit this BUG() if they used nand_scan()
    and were built as modules]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 3ff583f165cdfce7138f3f02d771fcb9d8f99e5e..ce7b2cab5762e5854cc4a11175876a53162e6215 100644 (file)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -3979,7 +3979,6 @@ static int nand_dt_init(struct mtd_info *mtd, struct nand_chip *chip,
  * This is the first phase of the normal nand_scan() function. It reads the
  * flash ID and sets up MTD fields accordingly.
  *
- * The mtd->owner field must be set to the module of the caller.
  */
 int nand_scan_ident(struct mtd_info *mtd, int maxchips,
                    struct nand_flash_dev *table)
@@ -4403,19 +4402,12 @@ EXPORT_SYMBOL(nand_scan_tail);
  *
  * This fills out all the uninitialized function pointers with the defaults.
  * The flash ID is read and the mtd/chip structures are filled with the
- * appropriate values. The mtd->owner field must be set to the module of the
- * caller.
+ * appropriate values.
  */
 int nand_scan(struct mtd_info *mtd, int maxchips)
 {
        int ret;
 
-       /* Many callers got this wrong, so check for it for a while... */
-       if (!mtd->owner && caller_is_module()) {
-               pr_crit("%s called with NULL mtd->owner!\n", __func__);
-               BUG();
-       }
-
        ret = nand_scan_ident(mtd, maxchips, NULL);
        if (!ret)
                ret = nand_scan_tail(mtd);