scsi: lpfc: avoid false-positive gcc-8 warning

This is an interesting regression with gcc-8, showing a harmless warning
for correct code:

In file included from include/linux/kernel.h:13:0,
                 ...
                 from drivers/scsi/lpfc/lpfc_debugfs.c:23:
include/linux/printk.h:301:2: error: 'eq' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
  ^~~~~~
In file included from drivers/scsi/lpfc/lpfc_debugfs.c:58:0:
drivers/scsi/lpfc/lpfc_debugfs.h:451:31: note: 'eq' was declared here

I managed to reduce the warning into a small test case for gcc-8 that I
reported in the gcc bugzilla[1].

As a workaround, this changes the logic to move the two assignments of
'eq' out of the conditions and instead make the index conditional.  This
works for all configurations I tried and avoids adding a bogus
initialization.

Acked-by: James Smart <james.smart@broadcom.com>
Link: [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81958
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/lpfc/lpfc_debugfs.h b/drivers/scsi/lpfc/lpfc_debugfs.h
index 7b7d314..c4edd87 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_debugfs.h
+++ b/drivers/scsi/lpfc/lpfc_debugfs.h
@@ -478,16 +478,16 @@ lpfc_debug_dump_cq(struct lpfc_hba *phba, int qtype, int wqidx)
                return;
 
        for (eqidx = 0; eqidx < phba->io_channel_irqs; eqidx++) {
-               eq = phba->sli4_hba.hba_eq[eqidx];
-               if (cq->assoc_qid == eq->queue_id)
+               if (cq->assoc_qid == phba->sli4_hba.hba_eq[eqidx]->queue_id)
                        break;
        }
        if (eqidx == phba->io_channel_irqs) {
                pr_err("Couldn't find EQ for CQ. Using EQ[0]\n");
                eqidx = 0;
-               eq = phba->sli4_hba.hba_eq[0];
        }
 
+       eq = phba->sli4_hba.hba_eq[eqidx];
+
        if (qtype == DUMP_FCP || qtype == DUMP_NVME)
                pr_err("%s CQ: WQ[Idx:%d|Qid%d]->CQ[Idx%d|Qid%d]"
                        "->EQ[Idx:%d|Qid:%d]:\n",