lseek(fd, n, SEEK_END) does *not* go to eof - n

When you copy some code, you are supposed to read it.  If nothing else,
there's a chance to spot and fix an obvious bug instead of sharing it...

X-Song: "I Got It From Agnes", by Tom Lehrer
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[ Tom Lehrer? You're dating yourself, Al ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/net/ethernet/brocade/bna/bnad_debugfs.c

@@ -244,7 +244,7 @@ bnad_debugfs_lseek(struct file *file, loff_t offset, int orig)
 		file->f_pos += offset;
 		break;
 	case 2:
-		file->f_pos = debug->buffer_len - offset;
+		file->f_pos = debug->buffer_len + offset;
 		break;
 	default:
 		return -EINVAL;

drivers/scsi/bfa/bfad_debugfs.c

@@ -186,7 +186,7 @@ bfad_debugfs_lseek(struct file *file, loff_t offset, int orig)
 		file->f_pos += offset;
 		break;
 	case 2:
-		file->f_pos = debug->buffer_len - offset;
+		file->f_pos = debug->buffer_len + offset;
 		break;
 	default:
 		return -EINVAL;

drivers/scsi/fnic/fnic_debugfs.c

@@ -174,7 +174,7 @@ static loff_t fnic_trace_debugfs_lseek(struct file *file,
 		pos = file->f_pos + offset;
 		break;
 	case 2:
-		pos = fnic_dbg_prt->buffer_len - offset;
+		pos = fnic_dbg_prt->buffer_len + offset;
 	}
 	return (pos < 0 || pos > fnic_dbg_prt->buffer_len) ?
 			  -EINVAL : (file->f_pos = pos);

drivers/scsi/lpfc/lpfc_debugfs.c

@@ -1178,7 +1178,7 @@ lpfc_debugfs_lseek(struct file *file, loff_t off, int whence)
 		pos = file->f_pos + off;
 		break;
 	case 2:
-		pos = debug->len - off;
+		pos = debug->len + off;
 	}
 	return (pos < 0 || pos > debug->len) ? -EINVAL : (file->f_pos = pos);
 }