staging: unisys: visorhba: simplify and enhance debugfs interface

debugfs info for each visorhba device is now presented by a file named of
the following form within the debugfs tree:

    visorhba/vbus<x>:dev<y>/info

where <x> is the vbus number, and <y> is the relative device number.

Also, the debugfs presentation function was converted to use the seq_file
interface, so that it could access the device context without resorting to
a global array.  This also simplified the function.

Signed-off-by: Tim Sell <Timothy.Sell@unisys.com>
Signed-off-by: David Kershner <david.kershner@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/unisys/visorhba/visorhba_main.c b/drivers/staging/unisys/visorhba/visorhba_main.c
index 5ea6bb2..6a21514 100644 (file)
--- a/drivers/staging/unisys/visorhba/visorhba_main.c
+++ b/drivers/staging/unisys/visorhba/visorhba_main.c
@@ -17,6 +17,7 @@
 #include <linux/skbuff.h>
 #include <linux/kthread.h>
 #include <linux/idr.h>
+#include <linux/seq_file.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_cmnd.h>
@@ -51,14 +52,7 @@ static int visorhba_pause(struct visor_device *dev,
 static int visorhba_resume(struct visor_device *dev,
                           visorbus_state_complete_func complete_func);
 
-static ssize_t info_debugfs_read(struct file *file, char __user *buf,
-                                size_t len, loff_t *offset);
-static int set_no_disk_inquiry_result(unsigned char *buf,
-                                     size_t len, bool is_lun0);
 static struct dentry *visorhba_debugfs_dir;
-static const struct file_operations debugfs_info_fops = {
-       .read = info_debugfs_read,
-};
 
 /* GUIDS for HBA channel type supported by this driver */
 static struct visor_channeltype_descriptor visorhba_channel_types[] = {
@@ -132,6 +126,9 @@ struct visorhba_devdata {
         * iovm, instead of raw pointers
         */
        struct idr idr;
+
+       struct dentry *debugfs_dir;
+       struct dentry *debugfs_info;
 };
 
 struct visorhba_devices_open {
@@ -667,66 +664,49 @@ static struct scsi_host_template visorhba_driver_template = {
 };
 
 /**
- *     info_debugfs_read - debugfs interface to dump visorhba states
- *     @file: Debug file
- *     @buf: buffer to send back to user
- *     @len: len that can be written to buf
- *     @offset: offset into buf
+ *     info_debugfs_show - debugfs interface to dump visorhba states
  *
- *     Dumps information about the visorhba driver and devices
- *     TODO: Make this per vhba
- *     Returns bytes_read
+ *      This presents a file in the debugfs tree named:
+ *          /visorhba/vbus<x>:dev<y>/info
  */
-static ssize_t info_debugfs_read(struct file *file, char __user *buf,
-                                size_t len, loff_t *offset)
+static int info_debugfs_show(struct seq_file *seq, void *v)
 {
-       ssize_t bytes_read = 0;
-       int str_pos = 0;
-       u64 phys_flags_addr;
-       int i;
-       struct visorhba_devdata *devdata;
-       char *vbuf;
-
-       if (len > MAX_BUF)
-               len = MAX_BUF;
-       vbuf = kzalloc(len, GFP_KERNEL);
-       if (!vbuf)
-               return -ENOMEM;
-
-       for (i = 0; i < VISORHBA_OPEN_MAX; i++) {
-               if (!visorhbas_open[i].devdata)
-                       continue;
-
-               devdata = visorhbas_open[i].devdata;
-
-               str_pos += scnprintf(vbuf + str_pos,
-                               len - str_pos, "max_buff_len:%u\n",
-                               devdata->max_buff_len);
-
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                               "\ninterrupts_rcvd = %llu, interrupts_disabled = %llu\n",
-                               devdata->interrupts_rcvd,
-                               devdata->interrupts_disabled);
-               str_pos += scnprintf(vbuf + str_pos,
-                               len - str_pos, "\ninterrupts_notme = %llu,\n",
-                               devdata->interrupts_notme);
-               phys_flags_addr = virt_to_phys((__force  void *)
-                                              devdata->flags_addr);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos,
-                               "flags_addr = %p, phys_flags_addr=0x%016llx, FeatureFlags=%llu\n",
-                               devdata->flags_addr, phys_flags_addr,
-                               (__le64)readq(devdata->flags_addr));
-               str_pos += scnprintf(vbuf + str_pos,
-                       len - str_pos, "acquire_failed_cnt:%llu\n",
-                       devdata->acquire_failed_cnt);
-               str_pos += scnprintf(vbuf + str_pos, len - str_pos, "\n");
+       struct visorhba_devdata *devdata = seq->private;
+
+       seq_printf(seq, "max_buff_len = %u\n", devdata->max_buff_len);
+       seq_printf(seq, "interrupts_rcvd = %llu\n", devdata->interrupts_rcvd);
+       seq_printf(seq, "interrupts_disabled = %llu\n",
+                  devdata->interrupts_disabled);
+       seq_printf(seq, "interrupts_notme = %llu\n",
+                  devdata->interrupts_notme);
+       seq_printf(seq, "flags_addr = %p\n", devdata->flags_addr);
+       if (devdata->flags_addr) {
+               u64 phys_flags_addr =
+                       virt_to_phys((__force  void *)devdata->flags_addr);
+               seq_printf(seq, "phys_flags_addr = 0x%016llx\n",
+                          phys_flags_addr);
+               seq_printf(seq, "FeatureFlags = %llu\n",
+                          (__le64)readq(devdata->flags_addr));
        }
+       seq_printf(seq, "acquire_failed_cnt = %llu\n",
+                  devdata->acquire_failed_cnt);
 
-       bytes_read = simple_read_from_buffer(buf, len, offset, vbuf, str_pos);
-       kfree(vbuf);
-       return bytes_read;
+       return 0;
 }
 
+static int info_debugfs_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, info_debugfs_show, inode->i_private);
+}
+
+static const struct file_operations info_debugfs_fops = {
+       .owner = THIS_MODULE,
+       .open = info_debugfs_open,
+       .read = seq_read,
+       .llseek = seq_lseek,
+       .release = single_release,
+};
+
 /**
  *     complete_taskmgmt_command - complete task management
  *     @cmdrsp: Response from the IOVM
@@ -1134,6 +1114,21 @@ static int visorhba_probe(struct visor_device *dev)
        devdata->dev = dev;
        dev_set_drvdata(&dev->device, devdata);
 
+       devdata->debugfs_dir = debugfs_create_dir(dev_name(&dev->device),
+                                                 visorhba_debugfs_dir);
+       if (!devdata->debugfs_dir) {
+               err = -ENOMEM;
+               goto err_scsi_remove_host;
+       }
+       devdata->debugfs_info =
+               debugfs_create_file("info", S_IRUSR | S_IRGRP,
+                                   devdata->debugfs_dir, devdata,
+                                   &info_debugfs_fops);
+       if (!devdata->debugfs_info) {
+               err = -ENOMEM;
+               goto err_debugfs_dir;
+       }
+
        init_waitqueue_head(&devdata->rsp_queue);
        spin_lock_init(&devdata->privlock);
        devdata->serverdown = false;
@@ -1144,11 +1139,11 @@ static int visorhba_probe(struct visor_device *dev)
                                  channel_header.features);
        err = visorbus_read_channel(dev, channel_offset, &features, 8);
        if (err)
-               goto err_scsi_remove_host;
+               goto err_debugfs_info;
        features |= ULTRA_IO_CHANNEL_IS_POLLING;
        err = visorbus_write_channel(dev, channel_offset, &features, 8);
        if (err)
-               goto err_scsi_remove_host;
+               goto err_debugfs_info;
 
        idr_init(&devdata->idr);
 
@@ -1160,6 +1155,12 @@ static int visorhba_probe(struct visor_device *dev)
 
        return 0;
 
+err_debugfs_info:
+       debugfs_remove(devdata->debugfs_info);
+
+err_debugfs_dir:
+       debugfs_remove_recursive(devdata->debugfs_dir);
+
 err_scsi_remove_host:
        scsi_remove_host(scsihost);
 
@@ -1191,6 +1192,8 @@ static void visorhba_remove(struct visor_device *dev)
        idr_destroy(&devdata->idr);
 
        dev_set_drvdata(&dev->device, NULL);
+       debugfs_remove(devdata->debugfs_info);
+       debugfs_remove_recursive(devdata->debugfs_dir);
 }
 
 /**
@@ -1201,21 +1204,12 @@ static void visorhba_remove(struct visor_device *dev)
  */
 static int visorhba_init(void)
 {
-       struct dentry *ret;
        int rc = -ENOMEM;
 
        visorhba_debugfs_dir = debugfs_create_dir("visorhba", NULL);
        if (!visorhba_debugfs_dir)
                return -ENOMEM;
 
-       ret = debugfs_create_file("info", S_IRUSR, visorhba_debugfs_dir, NULL,
-                                 &debugfs_info_fops);
-
-       if (!ret) {
-               rc = -EIO;
-               goto cleanup_debugfs;
-       }
-
        rc = visorbus_register_visor_driver(&visorhba_driver);
        if (rc)
                goto cleanup_debugfs;