[PATCH v2] scsi: mpi3mr: Emit uevent on controller diagnostic fault

[Salomon Dushimirimana <salomondush@google.com>]

Introduces a uevent mechanism to notify userspace when the controller
undergoes a reset due to a diagnostic fault. A new function,
mpi3mr_fault_event_emit(), is added and called from the reset path. This
function filters for a diagnostic fault type
(MPI3_SYSIF_HOST_DIAG_RESET_ACTION_DIAG_FAULT) and generates a uevent
containing details about the event:

- DRIVER: mpi3mr in this case
- HBA_NUM: scsi host id
- EVENT_TYPE: indicates fatal error
- RESET_TYPE: type of reset that has occurred
- RESET_REASON: specific reason for the reset

This will allow userspace tools to subscribe to these events and take
appropriate action.

Signed-off-by: Salomon Dushimirimana <salomondush@google.com>
---
Changes in v2:
- Addressed feedback from Bart regarding use of __free(kfree) and more

 drivers/scsi/mpi3mr/mpi3mr_fw.c | 37 +++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/scsi/mpi3mr/mpi3mr_fw.c b/drivers/scsi/mpi3mr/mpi3mr_fw.c
index 1d7901a8f0e40..a050c4535ad82 100644
--- a/drivers/scsi/mpi3mr/mpi3mr_fw.c
+++ b/drivers/scsi/mpi3mr/mpi3mr_fw.c
@@ -1623,6 +1623,42 @@ static inline void mpi3mr_set_diagsave(struct mpi3mr_ioc *mrioc)
 	writel(ioc_config, &mrioc->sysif_regs->ioc_configuration);
 }
 
+/**
+ * mpi3mr_fault_uevent_emit - Emit uevent for a controller diagnostic fault
+ * @mrioc: Pointer to the mpi3mr_ioc structure for the controller instance
+ * @reset_type: The type of reset that has occurred
+ * @reset_reason: The specific reason code for the reset
+ *
+ * This function is invoked when the controller undergoes a reset. It specifically
+ * filters for MPI3_SYSIF_HOST_DIAG_RESET_ACTION_DIAG_FAULT and ignores other
+ * reset types, such as soft resets.
+ */
+static void mpi3mr_fault_uevent_emit(struct mpi3mr_ioc *mrioc, u16 reset_type,
+	u16 reset_reason)
+{
+	struct kobj_uevent_env *env __free(kfree);
+
+	if (reset_type != MPI3_SYSIF_HOST_DIAG_RESET_ACTION_DIAG_FAULT)
+		return;
+
+	env = kzalloc(sizeof(*env), GFP_KERNEL);
+	if (!env)
+		return;
+
+	if (add_uevent_var(env, "DRIVER=%s", mrioc->driver_name))
+		return;
+	if (add_uevent_var(env, "HBA_NUM=%u", mrioc->id))
+		return;
+	if (add_uevent_var(env, "EVENT_TYPE=FATAL_ERROR"))
+		return;
+	if (add_uevent_var(env, "RESET_TYPE=%s", mpi3mr_reset_type_name(reset_type)))
+		return;
+	if (add_uevent_var(env, "RESET_REASON=%s", mpi3mr_reset_rc_name(reset_reason)))
+		return;
+
+	kobject_uevent_env(&mrioc->shost->shost_gendev.kobj, KOBJ_CHANGE, env->envp);
+}
+
 /**
  * mpi3mr_issue_reset - Issue reset to the controller
  * @mrioc: Adapter reference
@@ -1741,6 +1777,7 @@ static int mpi3mr_issue_reset(struct mpi3mr_ioc *mrioc, u16 reset_type,
 	    ioc_config);
 	if (retval)
 		mrioc->unrecoverable = 1;
+	mpi3mr_fault_uevent_emit(mrioc, reset_type, reset_reason);
 	return retval;
 }
 
-- 
2.50.0.727.gbf7dc18ff4-goog