scsi: hisi_sas: Add debugfs file structure for IOST cache

Create a file structure which was used to save the memory address for IOST
cache at debugfs. This structure is bound to the corresponding debugfs
file, it can help callback function of debugfs file to get what it needs.

Link: https://lore.kernel.org/r/1571926105-74636-13-git-send-email-john.garry@huawei.comSigned-off-by: Luo Jiaxing <luojiaxing@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas.h

@@ -351,6 +351,10 @@ struct hisi_sas_debugfs_itct {
 	struct hisi_sas_itct *itct;
 };
 
+struct hisi_sas_debugfs_iost_cache {
+	struct hisi_sas_iost_itct_cache *cache;
+};
+
 struct hisi_hba {
 	/* This must be the first element, used by SHOST_TO_SAS_HA */
 	struct sas_ha_struct *p;
@@ -438,8 +442,8 @@ struct hisi_hba {
 	struct hisi_sas_debugfs_dq debugfs_dq[HISI_SAS_MAX_QUEUES];
 	struct hisi_sas_debugfs_iost debugfs_iost;
 	struct hisi_sas_debugfs_itct debugfs_itct;
-	u64 *debugfs_iost_cache;
 	u64 debugfs_timestamp;
+	struct hisi_sas_debugfs_iost_cache debugfs_iost_cache;
 	u64 *debugfs_itct_cache;
 
 	struct dentry *debugfs_dir;

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -2800,7 +2800,7 @@ static void hisi_sas_debugfs_snapshot_itct_reg(struct hisi_hba *hisi_hba)
 static void hisi_sas_debugfs_snapshot_iost_reg(struct hisi_hba *hisi_hba)
 {
 	int max_command_entries = HISI_SAS_MAX_COMMANDS;
-	void *cachebuf = hisi_hba->debugfs_iost_cache;
+	void *cachebuf = hisi_hba->debugfs_iost_cache.cache;
 	void *databuf = hisi_hba->debugfs_iost.iost;
 	struct hisi_sas_iost *iost;
 	int i;
@@ -3088,9 +3088,8 @@ static const struct file_operations hisi_sas_debugfs_iost_fops = {
 
 static int hisi_sas_debugfs_iost_cache_show(struct seq_file *s, void *p)
 {
-	struct hisi_hba *hisi_hba = s->private;
-	struct hisi_sas_iost_itct_cache *iost_cache =
-		(struct hisi_sas_iost_itct_cache *)hisi_hba->debugfs_iost_cache;
+	struct hisi_sas_debugfs_iost_cache *debugfs_iost_cache = s->private;
+	struct hisi_sas_iost_itct_cache *iost_cache = debugfs_iost_cache->cache;
 	u32 cache_size = HISI_SAS_IOST_ITCT_CACHE_DW_SZ * 4;
 	int i, tab_idx;
 	__le64 *iost;
@@ -3250,7 +3249,8 @@ static void hisi_sas_debugfs_create_files(struct hisi_hba *hisi_hba)
 			    &hisi_hba->debugfs_iost,
 			    &hisi_sas_debugfs_iost_fops);
 
-	debugfs_create_file("iost_cache", 0400, dump_dentry, hisi_hba,
+	debugfs_create_file("iost_cache", 0400, dump_dentry,
+			    &hisi_hba->debugfs_iost_cache,
 			    &hisi_sas_debugfs_iost_cache_fops);
 
 	debugfs_create_file("itct", 0400, dump_dentry,
@@ -3716,7 +3716,7 @@ static void hisi_sas_debugfs_release(struct hisi_hba *hisi_hba)
 	struct device *dev = hisi_hba->dev;
 	int i;
 
-	devm_kfree(dev, hisi_hba->debugfs_iost_cache);
+	devm_kfree(dev, hisi_hba->debugfs_iost_cache.cache);
 	devm_kfree(dev, hisi_hba->debugfs_itct_cache);
 	devm_kfree(dev, hisi_hba->debugfs_iost.iost);
 
@@ -3793,8 +3793,8 @@ static int hisi_sas_debugfs_alloc(struct hisi_hba *hisi_hba)
 	sz = HISI_SAS_IOST_ITCT_CACHE_NUM *
 	     sizeof(struct hisi_sas_iost_itct_cache);
 
-	hisi_hba->debugfs_iost_cache = devm_kmalloc(dev, sz, GFP_KERNEL);
-	if (!hisi_hba->debugfs_iost_cache)
+	hisi_hba->debugfs_iost_cache.cache = devm_kmalloc(dev, sz, GFP_KERNEL);
+	if (!hisi_hba->debugfs_iost_cache.cache)
 		goto fail;
 
 	sz = HISI_SAS_IOST_ITCT_CACHE_NUM *