Fix crash on driver load due to cpu affinity logic

Signed-off-by: James Smart <james.sm...@emulex.com>

 ---

 lpfc_attr.c |    5 ++++-
 lpfc_init.c |   28 +++++++++++++++++++++++-----
 2 files changed, 27 insertions(+), 6 deletions(-)


diff -upNr a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
--- a/drivers/scsi/lpfc/lpfc_attr.c     2013-09-06 10:58:19.799132439 -0400
+++ b/drivers/scsi/lpfc/lpfc_attr.c     2013-09-06 10:58:46.749133052 -0400
@@ -4013,8 +4013,11 @@ LPFC_ATTR_R(ack0, 0, 0, 1, "Enable ACK0
 # For [0], FCP commands are issued to Work Queues ina round robin fashion.
 # For [1], FCP commands are issued to a Work Queue associated with the
 #          current CPU.
+# It would be set to 1 by the driver if it's able to set up cpu affinity
+# for FCP I/Os through Work Queue associated with the current CPU. Otherwise,
+# roundrobin scheduling of FCP I/Os through WQs will be used.
 */
-LPFC_ATTR_RW(fcp_io_sched, 0, 0, 1, "Determine scheduling algrithmn for "
+LPFC_ATTR_RW(fcp_io_sched, 0, 0, 1, "Determine scheduling algorithm for "
                "issuing commands [0] - Round Robin, [1] - Current CPU");
 
 /*
diff -upNr a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
--- a/drivers/scsi/lpfc/lpfc_init.c     2013-09-06 10:58:19.639132435 -0400
+++ b/drivers/scsi/lpfc/lpfc_init.c     2013-09-06 10:58:46.769133053 -0400
@@ -8399,7 +8399,8 @@ static int
 lpfc_sli4_set_affinity(struct lpfc_hba *phba, int vectors)
 {
        int i, idx, saved_chann, used_chann, cpu, phys_id;
-       int max_phys_id, num_io_channel, first_cpu;
+       int max_phys_id, min_phys_id;
+       int num_io_channel, first_cpu, chan;
        struct lpfc_vector_map_info *cpup;
 #ifdef CONFIG_X86
        struct cpuinfo_x86 *cpuinfo;
@@ -8417,6 +8418,7 @@ lpfc_sli4_set_affinity(struct lpfc_hba *
                phba->sli4_hba.num_present_cpu));
 
        max_phys_id = 0;
+       min_phys_id = 0xff;
        phys_id = 0;
        num_io_channel = 0;
        first_cpu = LPFC_VECTOR_MAP_EMPTY;
@@ -8440,9 +8442,12 @@ lpfc_sli4_set_affinity(struct lpfc_hba *
 
                if (cpup->phys_id > max_phys_id)
                        max_phys_id = cpup->phys_id;
+               if (cpup->phys_id < min_phys_id)
+                       min_phys_id = cpup->phys_id;
                cpup++;
        }
 
+       phys_id = min_phys_id;
        /* Now associate the HBA vectors with specific CPUs */
        for (idx = 0; idx < vectors; idx++) {
                cpup = phba->sli4_hba.cpu_map;
@@ -8453,13 +8458,25 @@ lpfc_sli4_set_affinity(struct lpfc_hba *
                        for (i = 1; i < max_phys_id; i++) {
                                phys_id++;
                                if (phys_id > max_phys_id)
-                                       phys_id = 0;
+                                       phys_id = min_phys_id;
                                cpu = lpfc_find_next_cpu(phba, phys_id);
                                if (cpu == LPFC_VECTOR_MAP_EMPTY)
                                        continue;
                                goto found;
                        }
 
+                       /* Use round robin for scheduling */
+                       phba->cfg_fcp_io_sched = LPFC_FCP_SCHED_ROUND_ROBIN;
+                       chan = 0;
+                       cpup = phba->sli4_hba.cpu_map;
+                       for (i = 0; i < phba->sli4_hba.num_present_cpu; i++) {
+                               cpup->channel_id = chan;
+                               cpup++;
+                               chan++;
+                               if (chan >= phba->cfg_fcp_io_channel)
+                                       chan = 0;
+                       }
+
                        lpfc_printf_log(phba, KERN_ERR, LOG_INIT,
                                        "3329 Cannot set affinity:"
                                        "Error mapping vector %d (%d)\n",
@@ -8497,7 +8514,7 @@ found:
                /* Spread vector mapping across multple physical CPU nodes */
                phys_id++;
                if (phys_id > max_phys_id)
-                       phys_id = 0;
+                       phys_id = min_phys_id;
        }
 
        /*
@@ -8507,7 +8524,7 @@ found:
         * Base the remaining IO channel assigned, to IO channels already
         * assigned to other CPUs on the same phys_id.
         */
-       for (i = 0; i <= max_phys_id; i++) {
+       for (i = min_phys_id; i <= max_phys_id; i++) {
                /*
                 * If there are no io channels already mapped to
                 * this phys_id, just round robin thru the io_channels.
@@ -8589,10 +8606,11 @@ out:
        if (num_io_channel != phba->sli4_hba.num_present_cpu)
                lpfc_printf_log(phba, KERN_ERR, LOG_INIT,
                                "3333 Set affinity mismatch:"
-                               "%d chann != %d cpus: %d vactors\n",
+                               "%d chann != %d cpus: %d vectors\n",
                                num_io_channel, phba->sli4_hba.num_present_cpu,
                                vectors);
 
+       /* Enable using cpu affinity for scheduling */
        phba->cfg_fcp_io_sched = LPFC_FCP_SCHED_BY_CPU;
        return 1;
 }



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