[bug report] UBI: Fastmap: Do not add vol if it already exists

[Dan Carpenter]

Hello shengyong,

The patch e96a8a3bb671: "UBI: Fastmap: Do not add vol if it already
exists" from May 26, 2015, leads to the following static checker
warning:

	drivers/mtd/ubi/fastmap.c:712 ubi_attach_fastmap()
	warn: PTR_ERR(av) is never (-22)

drivers/mtd/ubi/fastmap.c
   703  
   704                  av = add_vol(ai, be32_to_cpu(fmvhdr->vol_id),
   705                               be32_to_cpu(fmvhdr->used_ebs),
   706                               be32_to_cpu(fmvhdr->data_pad),
   707                               fmvhdr->vol_type,
   708                               be32_to_cpu(fmvhdr->last_eb_bytes));
   709  
   710                  if (!av)
   711                          goto fail_bad;
   712                  if (PTR_ERR(av) == -EINVAL) {

av is either -EEXIST or -ENOMEM.  It's never -EINVAL.

   713                          ubi_err(ubi, "volume (ID %i) already exists",
   714                                  fmvhdr->vol_id);
   715                          goto fail_bad;
   716                  }
   717  

regards,
dan carpenter