diff mbox series

[v5,01/10] scsi: scsi_debug: create scsi_debug directory in the debugfs filesystem

Message ID 20230922092906.2645265-2-haowenchao2@huawei.com
State New
Headers
Series scsi:scsi_debug: Add error injection for single device |

Commit Message

Wenchao Hao Sept. 22, 2023, 9:28 a.m. UTC 
  Create directory scsi_debug in the root of the debugfs filesystem.
Prepare to add interface for manage error injection.

Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Wenchao Hao <haowenchao2@huawei.com>
---
 drivers/scsi/scsi_debug.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Douglas Gilbert Sept. 28, 2023, 1:13 a.m. UTC | #1 
On 2023-09-22 05:28, Wenchao Hao wrote:
> Create directory scsi_debug in the root of the debugfs filesystem.
> Prepare to add interface for manage error injection.
> 
> Acked-by: Douglas Gilbert <dgilbert@interlog.com>
> Signed-off-by: Wenchao Hao <haowenchao2@huawei.com>
> ---
>   drivers/scsi/scsi_debug.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
> index 9c0af50501f9..35c336271b13 100644
> --- a/drivers/scsi/scsi_debug.c
> +++ b/drivers/scsi/scsi_debug.c
> @@ -41,6 +41,7 @@
>   #include <linux/random.h>
>   #include <linux/xarray.h>
>   #include <linux/prefetch.h>
> +#include <linux/debugfs.h>
>   
>   #include <net/checksum.h>
>   
> @@ -862,6 +863,8 @@ static const int device_qfull_result =
>   
>   static const int condition_met_result = SAM_STAT_CONDITION_MET;
>   
> +static struct dentry *sdebug_debugfs_root;
> +
>   
>   /* Only do the extra work involved in logical block provisioning if one or
>    * more of the lbpu, lbpws or lbpws10 parameters are given and we are doing
> @@ -7011,6 +7014,8 @@ static int __init scsi_debug_init(void)
>   		goto driver_unreg;
>   	}
>   
> +	sdebug_debugfs_root = debugfs_create_dir("scsi_debug", NULL);

debugfs_create_dir() can fail and return NULL. Looking at other drivers, most
seem to assume it will work. Since the scsi_debug driver is often used to test
abnormal situations, perhaps adding something like:
     if (!sdebug_debugfs_root)
         pr_info("%s: failed to create initial debugfs directory\n", __func__);

might save someone a bit of time if a NULL dereference on sdebug_debugfs_root
follows later. That is what the mpt3sas driver does.

Doug Gilbert

> +
>   	for (k = 0; k < hosts_to_add; k++) {
>   		if (want_store && k == 0) {
>   			ret = sdebug_add_host_helper(idx);
> @@ -7057,6 +7062,7 @@ static void __exit scsi_debug_exit(void)
>   
>   	sdebug_erase_all_stores(false);
>   	xa_destroy(per_store_ap);
> +	debugfs_remove(sdebug_debugfs_root);
>   }
>   
>   device_initcall(scsi_debug_init);
Wenchao Hao Sept. 28, 2023, 1:38 a.m. UTC | #2 
On 2023/9/28 9:13, Douglas Gilbert wrote:
> On 2023-09-22 05:28, Wenchao Hao wrote:
>> Create directory scsi_debug in the root of the debugfs filesystem.
>> Prepare to add interface for manage error injection.
>>
>> Acked-by: Douglas Gilbert <dgilbert@interlog.com>
>> Signed-off-by: Wenchao Hao <haowenchao2@huawei.com>
>> ---
>>   drivers/scsi/scsi_debug.c | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
>> index 9c0af50501f9..35c336271b13 100644
>> --- a/drivers/scsi/scsi_debug.c
>> +++ b/drivers/scsi/scsi_debug.c
>> @@ -41,6 +41,7 @@
>>   #include <linux/random.h>
>>   #include <linux/xarray.h>
>>   #include <linux/prefetch.h>
>> +#include <linux/debugfs.h>
>>   #include <net/checksum.h>
>> @@ -862,6 +863,8 @@ static const int device_qfull_result =
>>   static const int condition_met_result = SAM_STAT_CONDITION_MET;
>> +static struct dentry *sdebug_debugfs_root;
>> +
>>   /* Only do the extra work involved in logical block provisioning if one or
>>    * more of the lbpu, lbpws or lbpws10 parameters are given and we are doing
>> @@ -7011,6 +7014,8 @@ static int __init scsi_debug_init(void)
>>           goto driver_unreg;
>>       }
>> +    sdebug_debugfs_root = debugfs_create_dir("scsi_debug", NULL);
> 
> debugfs_create_dir() can fail and return NULL. Looking at other drivers, most
> seem to assume it will work. Since the scsi_debug driver is often used to test
> abnormal situations, perhaps adding something like:
>      if (!sdebug_debugfs_root)
>          pr_info("%s: failed to create initial debugfs directory\n", __func__);
> 
> might save someone a bit of time if a NULL dereference on sdebug_debugfs_root
> follows later. That is what the mpt3sas driver does.
> 

Yes, I would fix it by checking return value of debugfs related call
after your review suggestions for other patches.

> Doug Gilbert
> 
>> +
>>       for (k = 0; k < hosts_to_add; k++) {
>>           if (want_store && k == 0) {
>>               ret = sdebug_add_host_helper(idx);
>> @@ -7057,6 +7062,7 @@ static void __exit scsi_debug_exit(void)
>>       sdebug_erase_all_stores(false);
>>       xa_destroy(per_store_ap);
>> +    debugfs_remove(sdebug_debugfs_root);
>>   }
>>   device_initcall(scsi_debug_init);
> 
>
diff mbox series

Patch

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 9c0af50501f9..35c336271b13 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -41,6 +41,7 @@ 
 #include <linux/random.h>
 #include <linux/xarray.h>
 #include <linux/prefetch.h>
+#include <linux/debugfs.h>
 
 #include <net/checksum.h>
 
@@ -862,6 +863,8 @@  static const int device_qfull_result =
 
 static const int condition_met_result = SAM_STAT_CONDITION_MET;
 
+static struct dentry *sdebug_debugfs_root;
+
 
 /* Only do the extra work involved in logical block provisioning if one or
  * more of the lbpu, lbpws or lbpws10 parameters are given and we are doing
@@ -7011,6 +7014,8 @@  static int __init scsi_debug_init(void)
 		goto driver_unreg;
 	}
 
+	sdebug_debugfs_root = debugfs_create_dir("scsi_debug", NULL);
+
 	for (k = 0; k < hosts_to_add; k++) {
 		if (want_store && k == 0) {
 			ret = sdebug_add_host_helper(idx);
@@ -7057,6 +7062,7 @@  static void __exit scsi_debug_exit(void)
 
 	sdebug_erase_all_stores(false);
 	xa_destroy(per_store_ap);
+	debugfs_remove(sdebug_debugfs_root);
 }
 
 device_initcall(scsi_debug_init);