[MTD] [NAND] Replace -1 with -EBADMSG in nand error correction code

Magic numerical values are just bad style. Particularly so when
undocumented.

Signed-off-by: Jörn Engel <[e-mail]>
Signed-off-by: David Woodhouse <[e-mail]>

drivers/mtd/nand/diskonchip.c

···
 		}
 	}
 	/* If the parity is wrong, no rescue possible */
-	return parity ? -1 : nerr;
+	return parity ? -EBADMSG : nerr;
 }
 
 static void DoC_Delay(struct doc_priv *doc, unsigned short cycles)
···
 		WriteDOC(DOC_ECC_DIS, docptr, Mplus_ECCConf);
 	else
 		WriteDOC(DOC_ECC_DIS, docptr, ECCConf);
-	if (no_ecc_failures && (ret == -1)) {
+	if (no_ecc_failures && (ret == -EBADMSG)) {
 		printk(KERN_ERR "suppressing ECC failure\n");
 		ret = 0;
 	}

drivers/mtd/nand/nand_ecc.c

···
 	if(countbits(s0 | ((uint32_t)s1 << 8) | ((uint32_t)s2 <<16)) == 1)
 		return 1;
 
-	return -1;
+	return -EBADMSG;
 }
 EXPORT_SYMBOL(nand_correct_data);
 

lib/reed_solomon/decode_rs.c

···
 		 * deg(lambda) unequal to number of roots => uncorrectable
 		 * error detected
 		 */
-		count = -1;
+		count = -EBADMSG;
 		goto finish;
 	}
 	/*

lib/reed_solomon/reed_solomon.c

···
  *  The syndrome and parity uses a uint16_t data type to enable
  *  symbol size > 8. The calling code must take care of decoding of the
  *  syndrome result and the received parity before calling this code.
+ *  Returns the number of corrected bits or -EBADMSG for uncorrectable errors.
  */
 int decode_rs8(struct rs_control *rs, uint8_t *data, uint16_t *par, int len,
 	       uint16_t *s, int no_eras, int *eras_pos, uint16_t invmsk,
···
  *  @corr:	buffer to store correction bitmask on eras_pos
  *
  *  Each field in the data array contains up to symbol size bits of valid data.
+ *  Returns the number of corrected bits or -EBADMSG for uncorrectable errors.
  */
 int decode_rs16(struct rs_control *rs, uint16_t *data, uint16_t *par, int len,
 		uint16_t *s, int no_eras, int *eras_pos, uint16_t invmsk,