scsi: mpi3mr: Synchronous access b/w reset and tm thread for reply queue

When the task management thread processes reply queues while the reset
thread resets them, the task management thread accesses an invalid queue ID
(0xFFFF), set by the reset thread, which points to unallocated memory,
causing a crash.

Add flag 'io_admin_reset_sync' to synchronize access between the reset,
I/O, and admin threads. Before a reset, the reset handler sets this flag to
block I/O and admin processing threads. If any thread bypasses the initial
check, the reset thread waits up to 10 seconds for processing to finish. If
the wait exceeds 10 seconds, the controller is marked as unrecoverable.

Signed-off-by: Sumit Saxena <[email protected]>
Signed-off-by: Ranjan Kumar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>

Author: Ranjan Kumar

drivers/scsi/mpi3mr/mpi3mr.h

@@ -1100,6 +1100,7 @@ struct scmd_priv {
  * @ts_update_interval: Timestamp update interval
  * @reset_in_progress: Reset in progress flag
  * @unrecoverable: Controller unrecoverable flag
+ * @io_admin_reset_sync: Manage state of I/O ops during an admin reset process
  * @prev_reset_result: Result of previous reset
  * @reset_mutex: Controller reset mutex
  * @reset_waitq: Controller reset  wait queue
@@ -1292,6 +1293,7 @@ struct mpi3mr_ioc {
 	u16 ts_update_interval;
 	u8 reset_in_progress;
 	u8 unrecoverable;
+	u8 io_admin_reset_sync;
 	int prev_reset_result;
 	struct mutex reset_mutex;
 	wait_queue_head_t reset_waitq;

drivers/scsi/mpi3mr/mpi3mr_fw.c

@@ -17,7 +17,7 @@ static void mpi3mr_process_factsdata(struct mpi3mr_ioc *mrioc,
 	struct mpi3_ioc_facts_data *facts_data);
 static void mpi3mr_pel_wait_complete(struct mpi3mr_ioc *mrioc,
 	struct mpi3mr_drv_cmd *drv_cmd);
-
+static int mpi3mr_check_op_admin_proc(struct mpi3mr_ioc *mrioc);
 static int poll_queues;
 module_param(poll_queues, int, 0444);
 MODULE_PARM_DESC(poll_queues, "Number of queues for io_uring poll mode. (Range 1 - 126)");
@@ -459,7 +459,7 @@ int mpi3mr_process_admin_reply_q(struct mpi3mr_ioc *mrioc)
 	}
 
 	do {
-		if (mrioc->unrecoverable)
+		if (mrioc->unrecoverable || mrioc->io_admin_reset_sync)
 			break;
 
 		mrioc->admin_req_ci = le16_to_cpu(reply_desc->request_queue_ci);
@@ -554,7 +554,7 @@ int mpi3mr_process_op_reply_q(struct mpi3mr_ioc *mrioc,
 	}
 
 	do {
-		if (mrioc->unrecoverable)
+		if (mrioc->unrecoverable || mrioc->io_admin_reset_sync)
 			break;
 
 		req_q_idx = le16_to_cpu(reply_desc->request_queue_id) - 1;
@@ -4411,6 +4411,7 @@ int mpi3mr_reinit_ioc(struct mpi3mr_ioc *mrioc, u8 is_resume)
 		goto out_failed_noretry;
 	}
 
+	mrioc->io_admin_reset_sync = 0;
 	if (is_resume || mrioc->block_on_pci_err) {
 		dprint_reset(mrioc, "setting up single ISR\n");
 		retval = mpi3mr_setup_isr(mrioc, 1);
@@ -5289,6 +5290,55 @@ void mpi3mr_pel_get_seqnum_complete(struct mpi3mr_ioc *mrioc,
 	drv_cmd->retry_count = 0;
 }
 
+/**
+ * mpi3mr_check_op_admin_proc -
+ * @mrioc: Adapter instance reference
+ *
+ * Check if any of the operation reply queues
+ * or the admin reply queue are currently in use.
+ * If any queue is in use, this function waits for
+ * a maximum of 10 seconds for them to become available.
+ *
+ * Return: 0 on success, non-zero on failure.
+ */
+static int mpi3mr_check_op_admin_proc(struct mpi3mr_ioc *mrioc)
+{
+
+	u16 timeout = 10 * 10;
+	u16 elapsed_time = 0;
+	bool op_admin_in_use = false;
+
+	do {
+		op_admin_in_use = false;
+
+		/* Check admin_reply queue first to exit early */
+		if (atomic_read(&mrioc->admin_reply_q_in_use) == 1)
+			op_admin_in_use = true;
+		else {
+			/* Check op_reply queues */
+			int i;
+
+			for (i = 0; i < mrioc->num_queues; i++) {
+				if (atomic_read(&mrioc->op_reply_qinfo[i].in_use) == 1) {
+					op_admin_in_use = true;
+					break;
+				}
+			}
+		}
+
+		if (!op_admin_in_use)
+			break;
+
+		msleep(100);
+
+	} while (++elapsed_time < timeout);
+
+	if (op_admin_in_use)
+		return 1;
+
+	return 0;
+}
+
 /**
  * mpi3mr_soft_reset_handler - Reset the controller
  * @mrioc: Adapter instance reference
@@ -5369,6 +5419,7 @@ int mpi3mr_soft_reset_handler(struct mpi3mr_ioc *mrioc,
 	mpi3mr_wait_for_host_io(mrioc, MPI3MR_RESET_HOST_IOWAIT_TIMEOUT);
 
 	mpi3mr_ioc_disable_intr(mrioc);
+	mrioc->io_admin_reset_sync = 1;
 
 	if (snapdump) {
 		mpi3mr_set_diagsave(mrioc);
@@ -5396,6 +5447,16 @@ int mpi3mr_soft_reset_handler(struct mpi3mr_ioc *mrioc,
 		ioc_err(mrioc, "Failed to issue soft reset to the ioc\n");
 		goto out;
 	}
+
+	retval = mpi3mr_check_op_admin_proc(mrioc);
+	if (retval) {
+		ioc_err(mrioc, "Soft reset failed due to an Admin or I/O queue polling\n"
+				"thread still processing replies even after a 10 second\n"
+				"timeout. Marking the controller as unrecoverable!\n");
+
+		goto out;
+	}
+
 	if (mrioc->num_io_throttle_group !=
 	    mrioc->facts.max_io_throttle_group) {
 		ioc_err(mrioc,