scsi: hisi_sas: Directly snapshot registers when executing a reset

mainline inclusion
from mainline-master
commit 2c74cb1f
category: bugfix
bugzilla: 175270
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2c74cb1f9222ebfcc204c02018275ad167d25212

------------------------------------------------------------------------

The debugfs snapshot should be executed before the reset occurs to ensure
that the register contents are saved properly.

As such, it is incorrect to queue the debugfs dump when running a reset as
the reset will occur prior to the snapshot work item is handler.

Therefore, directly snapshot registers in the reset work handler.

Link: https://lore.kernel.org/r/1617709711-195853-5-git-send-email-john.garry@huawei.comSigned-off-by: NJianqin Xie <xiejianqin@hisilicon.com>
Signed-off-by: NLuo Jiaxing <luojiaxing@huawei.com>
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NOuyangdelong <ouyangdelong@huawei.com>
Signed-off-by: NNifujia <nifujia1@hisilicon.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/scsi/hisi_sas/hisi_sas.h

@@ -346,6 +346,7 @@ struct hisi_sas_hw {
 				u8 reg_index, u8 reg_count, u8 *write_data);
 	void (*wait_cmds_complete_timeout)(struct hisi_hba *hisi_hba,
 					   int delay_ms, int timeout_ms);
+	void (*debugfs_snapshot_regs)(struct hisi_hba *hisi_hba);
 	int complete_hdr_size;
 	struct scsi_host_template *sht;
 };

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -1568,21 +1568,26 @@ void hisi_sas_controller_reset_done(struct hisi_hba *hisi_hba)
 }
 EXPORT_SYMBOL_GPL(hisi_sas_controller_reset_done);
 
-static int hisi_sas_controller_reset(struct hisi_hba *hisi_hba)
+static int hisi_sas_controller_prereset(struct hisi_hba *hisi_hba)
 {
-	struct device *dev = hisi_hba->dev;
-	struct Scsi_Host *shost = hisi_hba->shost;
-	int rc;
-
-	if (hisi_sas_debugfs_enable && hisi_hba->debugfs_itct[0].itct)
-		queue_work(hisi_hba->wq, &hisi_hba->debugfs_work);
-
 	if (!hisi_hba->hw->soft_reset)
 		return -1;
 
 	if (test_and_set_bit(HISI_SAS_RESET_BIT, &hisi_hba->flags))
 		return -1;
 
+	if (hisi_sas_debugfs_enable && hisi_hba->debugfs_itct[0].itct)
+		hisi_hba->hw->debugfs_snapshot_regs(hisi_hba);
+
+	return 0;
+}
+
+static int hisi_sas_controller_reset(struct hisi_hba *hisi_hba)
+{
+	struct device *dev = hisi_hba->dev;
+	struct Scsi_Host *shost = hisi_hba->shost;
+	int rc;
+
 	dev_info(dev, "controller resetting...\n");
 	hisi_sas_controller_reset_prepare(hisi_hba);
 
@@ -2471,6 +2476,9 @@ void hisi_sas_rst_work_handler(struct work_struct *work)
 	struct hisi_hba *hisi_hba =
 		container_of(work, struct hisi_hba, rst_work);
 
+	if (hisi_sas_controller_prereset(hisi_hba))
+		return;
+
 	hisi_sas_controller_reset(hisi_hba);
 }
 EXPORT_SYMBOL_GPL(hisi_sas_rst_work_handler);
@@ -2480,8 +2488,12 @@ void hisi_sas_sync_rst_work_handler(struct work_struct *work)
 	struct hisi_sas_rst *rst =
 		container_of(work, struct hisi_sas_rst, work);
 
+	if (hisi_sas_controller_prereset(rst->hisi_hba))
+		goto rst_complete;
+
 	if (!hisi_sas_controller_reset(rst->hisi_hba))
 		rst->done = true;
+rst_complete:
 	complete(rst->completion);
 }
 EXPORT_SYMBOL_GPL(hisi_sas_sync_rst_work_handler);

drivers/scsi/hisi_sas/hisi_sas_v3_hw.c

@@ -531,6 +531,7 @@ module_param(prot_mask, int, 0);
 MODULE_PARM_DESC(prot_mask, " host protection capabilities mask, def=0x0 ");
 
 static void debugfs_work_handler_v3_hw(struct work_struct *work);
+static void debugfs_snapshot_regs_v3_hw(struct hisi_hba *hisi_hba);
 
 static u32 hisi_sas_read32(struct hisi_hba *hisi_hba, u32 off)
 {
@@ -3183,6 +3184,7 @@ static const struct hisi_sas_hw hisi_sas_v3_hw = {
 	.get_events = phy_get_events_v3_hw,
 	.write_gpio = write_gpio_v3_hw,
 	.wait_cmds_complete_timeout = wait_cmds_complete_timeout_v3_hw,
+	.debugfs_snapshot_regs = debugfs_snapshot_regs_v3_hw,
 };
 
 static struct Scsi_Host *
@@ -3667,6 +3669,19 @@ static void debugfs_create_files_v3_hw(struct hisi_hba *hisi_hba)
 
 static void debugfs_snapshot_regs_v3_hw(struct hisi_hba *hisi_hba)
 {
+	int debugfs_dump_index = hisi_hba->debugfs_dump_index;
+	struct device *dev = hisi_hba->dev;
+	u64 timestamp = local_clock();
+
+	if (debugfs_dump_index >= hisi_sas_debugfs_dump_count) {
+		dev_warn(dev, "dump count exceeded!\n");
+		return;
+	}
+
+	do_div(timestamp, NSEC_PER_MSEC);
+	hisi_hba->debugfs_timestamp[debugfs_dump_index] = timestamp;
+	hisi_hba->debugfs_dump_index++;
+
 	debugfs_snapshot_prepare_v3_hw(hisi_hba);
 
 	debugfs_snapshot_global_reg_v3_hw(hisi_hba);
@@ -4409,20 +4424,8 @@ static void debugfs_work_handler_v3_hw(struct work_struct *work)
 {
 	struct hisi_hba *hisi_hba =
 		container_of(work, struct hisi_hba, debugfs_work);
-	int debugfs_dump_index = hisi_hba->debugfs_dump_index;
-	struct device *dev = hisi_hba->dev;
-	u64 timestamp = local_clock();
-
-	if (debugfs_dump_index >= hisi_sas_debugfs_dump_count) {
-		dev_warn(dev, "dump count exceeded!\n");
-		return;
-	}
-
-	do_div(timestamp, NSEC_PER_MSEC);
-	hisi_hba->debugfs_timestamp[debugfs_dump_index] = timestamp;
 
 	debugfs_snapshot_regs_v3_hw(hisi_hba);
-	hisi_hba->debugfs_dump_index++;
 }
 
 static void debugfs_release_v3_hw(struct hisi_hba *hisi_hba, int dump_index)