mtd: Replace the expert mode symbols with a single helper

Reduce the number of exported symbols by replacing:
- mtd_expert_analysis_warning (the error string)
- mtd_expert_analysis_mode (the boolean)
with a single helper:
- mtd_check_expert_analysis_mode

Calling this helper will both check/return the content of the internal
boolean -which is not exported anymore- and as well conditionally
WARN_ONCE() the user, like it was done before.

While on this function, make the error string local to the helper and
set it const. Only export this helper when CONFIG_DEBUG_FS is defined to
limit the growth of the Linux kernel size only for a debug feature on
production kernels.

Mechanically update all the consumers.

Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220128113414.1121924-1-miquel.raynal@bootlin.com

1 files changed, 6 insertions, 2 deletions

diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 1ffa933121f6..1b3fc8c71ab3 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -711,7 +711,11 @@ static inline int mtd_is_bitflip_or_eccerr(int err) {
 
 unsigned mtd_mmap_capabilities(struct mtd_info *mtd);
 
-extern char *mtd_expert_analysis_warning;
-extern bool mtd_expert_analysis_mode;
+#ifdef CONFIG_DEBUG_FS
+bool mtd_check_expert_analysis_mode(void);
+#else
+static inline bool mtd_check_expert_analysis_mode(void) { return false; }
+#endif
+
 
 #endif /* __MTD_MTD_H__ */