2023-09-22 09:40:53

by Wenchao Hao

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

Create directory scsi_debug in the root of the debugfs filesystem.
Prepare to add interface for manage error injection.

Acked-by: Douglas Gilbert <[email protected]>
Signed-off-by: Wenchao Hao <[email protected]>
---
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);
+
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);
--
2.32.0

2023-09-28 01:13:30

by Douglas Gilbert

Subject: Re: [PATCH v5 01/10] scsi: scsi_debug: create scsi_debug directory in the debugfs filesystem

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 <[email protected]>
> Signed-off-by: Wenchao Hao <[email protected]>
> ---
> 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);

2023-09-28 01:39:27

by Wenchao Hao

Subject: Re: [PATCH v5 01/10] scsi: scsi_debug: create scsi_debug directory in the debugfs filesystem

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 <[email protected]>
>> Signed-off-by: Wenchao Hao <[email protected]>
>> ---
>>   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);
>
>