From linux-mtd at lists.infradead.org  Sat Apr  2 23:59:01 2016
From: linux-mtd at lists.infradead.org (Linux-MTD Mailing List)
Date: Sun, 03 Apr 2016 06:59:01 +0000
Subject: mtd: nand: Drop mtd.owner requirement in nand_scan
Message-ID: <E1ambzx-00031u-OI@bombadil.infradead.org>

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=20c07a5bf094198ff2382aa5e7c930b3c9807792
Commit:     20c07a5bf094198ff2382aa5e7c930b3c9807792
Parent:     f55532a0c0b8bb6148f4e07853b876ef73bc69ca
Author:     Ezequiel Garc?a <ezequiel at vanguardiasur.com.ar>
AuthorDate: Fri Apr 1 18:29:23 2016 -0300
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Sat Apr 2 23:03:51 2016 -0700

    mtd: nand: Drop mtd.owner requirement in nand_scan
    
    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 at vanguardiasur.com.ar>
    Acked-by: Boris Brezillon <boris.brezillon at 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 at gmail.com>
---
 drivers/mtd/nand/nand_base.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index b6facac..557b846 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -4009,7 +4009,6 @@ static int nand_dt_init(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)
@@ -4429,19 +4428,12 @@ 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);


