[PATCH] qla2xxx: Fix NULL pointer dereference in target mode

[Gleb Chesnokov <gleb.chesnokov@scst.dev>]

When target mode is enabled, the pci_irq_get_affinity() function may return
a NULL value in qla_mapq_init_qp_cpu_map() due to the qla24xx_enable_msix()
code that handles IRQ settings for target mode. This leads to a crash due
to a NULL pointer dereference.

This patch fixes the issue by adding a check for the NULL value returned
by pci_irq_get_affinity() and introducing a 'cpu_mapped' boolean flag to
the qla_qpair structure, ensuring that the qpair's CPU affinity is updated
when it has not been mapped to a CPU.

Fixes: 1d201c81d4cc ("scsi: qla2xxx: Select qpair depending on which CPU 
post_cmd() gets called")

Signed-off-by: Gleb Chesnokov <gleb.chesnokov@scst.dev>
---
  drivers/scsi/qla2xxx/qla_def.h    | 1 +
  drivers/scsi/qla2xxx/qla_init.c   | 3 +++
  drivers/scsi/qla2xxx/qla_inline.h | 6 ++++++
  drivers/scsi/qla2xxx/qla_isr.c    | 3 +++
  4 files changed, 13 insertions(+)

diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index df5e5b7fdcfe..84aa3571be6d 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -3796,6 +3796,7 @@ struct qla_qpair {
      uint64_t retry_term_jiff;
      struct qla_tgt_counters tgt_counters;
      uint16_t cpuid;
+    bool cpu_mapped;
      struct qla_fw_resources fwres ____cacheline_aligned;
      struct  qla_buf_pool buf_pool;
      u32    cmd_cnt;
diff --git a/drivers/scsi/qla2xxx/qla_init.c 
b/drivers/scsi/qla2xxx/qla_init.c
index ec0423ec6681..1a955c3ff3d6 100644
--- a/drivers/scsi/qla2xxx/qla_init.c
+++ b/drivers/scsi/qla2xxx/qla_init.c
@@ -9426,6 +9426,9 @@ struct qla_qpair *qla2xxx_create_qpair(struct 
scsi_qla_host *vha, int qos,
          qpair->rsp->req = qpair->req;
          qpair->rsp->qpair = qpair;

+        if (!qpair->cpu_mapped)
+            qla_cpu_update(qpair, raw_smp_processor_id());
+
          if (IS_T10_PI_CAPABLE(ha) && ql2xenabledif) {
              if (ha->fw_attributes & BIT_4)
                  qpair->difdix_supported = 1;
diff --git a/drivers/scsi/qla2xxx/qla_inline.h 
b/drivers/scsi/qla2xxx/qla_inline.h
index cce6e425c121..a6e2c7d4ff87 100644
--- a/drivers/scsi/qla2xxx/qla_inline.h
+++ b/drivers/scsi/qla2xxx/qla_inline.h
@@ -538,12 +538,18 @@ qla_mapq_init_qp_cpu_map(struct qla_hw_data *ha,

      if (!ha->qp_cpu_map)
          return;
+
      mask = pci_irq_get_affinity(ha->pdev, msix->vector_base0);
+    if (!mask)
+        return;
+
      qpair->cpuid = cpumask_first(mask);
      for_each_cpu(cpu, mask) {
          ha->qp_cpu_map[cpu] = qpair;
      }
      msix->cpuid = qpair->cpuid;
+
+    qpair->cpu_mapped = true;
  }

  static inline void
diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index 71feda2cdb63..245e3a5d81fd 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -3770,6 +3770,9 @@ void qla24xx_process_response_queue(struct 
scsi_qla_host *vha,

      if (rsp->qpair->cpuid != smp_processor_id() || 
!rsp->qpair->rcv_intr) {
          rsp->qpair->rcv_intr = 1;
+
+        if (!rsp->qpair->cpu_mapped)
+            qla_cpu_update(rsp->qpair, raw_smp_processor_id());
      }

  #define __update_rsp_in(_is_shadow_hba, _rsp, _rsp_in)            \
-- 
2.40.1