mtd: fix merge conflict resolution breakage

This patch fixes merge conflict resolution breakage introduced by merge
d3712b9dfcf4 ("Merge tag 'for-linus' of git://github.com/prasad-joshi/logfs_upstream").

The commit changed 'mtd_can_have_bb()' function and made it always
return zero, which is incorrect.  Instead, we need it to return whether
the underlying flash device can have bad eraseblocks or not.  UBI needs
this information because it affects how it handles the underlying flash.
E.g., if the underlying flash is NOR, it cannot have bad blocks and any
write or erase error is fatal, and all we can do is to switch to R/O
mode.  We do not need to reserve a pool of good eraseblocks for bad
eraseblocks handling, and so on.

This patch also removes 'mtd_can_have_bb()' invocations from Logfs to
ensure correct Logfs behavior.

I've tested that with this patch UBI works on top of NOR and NAND
flashes emulated by mtdram and nandsim correspondingly.

This patch is based on patch from Linus Torvalds.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Acked-by: Jörn Engel <joern@logfs.org>
Acked-by: Prasad Joshi <prasadjoshi.linux@gmail.com>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/logfs/dev_mtd.c b/fs/logfs/dev_mtd.c
index e97404d611e0abf4f627d6c080aea0c0739422f0..9c501449450dc9be6891e5d9c1a035ca31b5687b 100644 (file)
--- a/fs/logfs/dev_mtd.c
+++ b/fs/logfs/dev_mtd.c
@@ -152,9 +152,6 @@ static struct page *logfs_mtd_find_first_sb(struct super_block *sb, u64 *ofs)
        filler_t *filler = logfs_mtd_readpage;
        struct mtd_info *mtd = super->s_mtd;
 
-       if (!mtd_can_have_bb(mtd))
-               return NULL;
-
        *ofs = 0;
        while (mtd_block_isbad(mtd, *ofs)) {
                *ofs += mtd->erasesize;
@@ -172,9 +169,6 @@ static struct page *logfs_mtd_find_last_sb(struct super_block *sb, u64 *ofs)
        filler_t *filler = logfs_mtd_readpage;
        struct mtd_info *mtd = super->s_mtd;
 
-       if (!mtd_can_have_bb(mtd))
-               return NULL;
-
        *ofs = mtd->size - mtd->erasesize;
        while (mtd_block_isbad(mtd, *ofs)) {
                *ofs -= mtd->erasesize;

diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 221295208fd0bf18fd4302955558be0a3f4f05e9..887ebe318c75e1d9b5a2cc14ec9dddfd1eca7b8a 100644 (file)
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -489,7 +489,7 @@ static inline int mtd_has_oob(const struct mtd_info *mtd)
 
 static inline int mtd_can_have_bb(const struct mtd_info *mtd)
 {
-       return 0;
+       return !!mtd->block_isbad;
 }
 
        /* Kernel-side ioctl definitions */