Bug 194539

Summary: Dead code in linux/drivers/scsi/lpfc/lpfc_scsi.c
Product: Drivers Reporter: shqking (shqking)
Component: OtherAssignee: drivers_other
Status: NEW ---    
Severity: normal    
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 4.10-rc7 Subsystem:
Regression: No Bisected commit-id:

Description shqking 2017-02-10 08:00:32 UTC 
Suspicious dead code is found in linux/drivers/scsi/lpfc/lpfc_scsi.c:1927 (https://github.com/torvalds/linux/blob/master/drivers/scsi/lpfc/lpfc_scsi.c#L1927).

The code snippet is as follows.

    1927 if (lpfc_cmd_protect(sc, LPFC_CHECK_PROTECT_GUARD))
    1928     bf_set(pde6_ce, pde6, checking);
    1929 else
    1930     bf_set(pde6_ce, pde6, 0);

According to the definition of function lpfc_cmd_protect at line 155, it returns 1 always. Hence, the ELSE branch will never execute, i.e. dead code.

    154 static inline unsigned
    155 lpfc_cmd_protect(struct scsi_cmnd *sc, int flag)
    156 {
    157	    return 1;
    158 }

Since I'm not expert in kernel source code, I'm not sure whether it is an implementation defect or I was missing something?

Regards,
shqking