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SubjectRe: [PATCH 1/4] scsi: core: constify pointer to scsi_host_template
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On 25/04/2022 10:22, Krzysztof Kozlowski wrote:
> On 25/04/2022 10:58, John Garry wrote:
>> On 20/04/2022 08:03, Christoph Hellwig wrote:
>>>> The standard flow is:
>>>>
>>>> shost = scsi_host_alloc(sht, )
>>>>
>>>> // modify shost, like
>>>> shost->cmd_per_lun = 5;
>>>>
>>>> scsi_add_host(shost)
>>>>
>>>> Is there some reason for which those two drivers can't follow that?
>>> I think they should. Method tables should not be mutable data.
>>> .
>>
>> Hi Krzysztof,
>>
>> Do you have any interest in going further with your work and trying to
>> change all SCSI driver instances of scsi_host_template to be const? I am
>> not sure if it has been attempted before...
>
> I can work on this, but what about the SCSI core modifying the template?

I hope that this isn't a can of worms...

> For example scsi_proc_hostdir_rm(): 'present' and 'proc_dir' members.
> Where should they be stored? Should they be moved to the Scsi_Host?
>

I don't think scsi_Host is appropriate as this is per-scsi host
template, unless you see a way to do it that way. Alternatively we could
keep a separate list of registered sht, like this:

struct sht_proc_dir {
int cnt;
struct list_head list;
struct proc_dir_entry *proc_dir;
struct scsi_host_template *sht;
};
static LIST_HEAD(sht_proc_dir_list);

void scsi_proc_hostdir_add(struct scsi_host_template *sht)
{
struct sht_proc_dir *dir;

if (!sht->show_info)
return;

mutex_lock(&global_host_template_mutex);
list_for_each_entry(dir, &sht_proc_dir_list, list) {
if (dir->sht == sht) {
dir->cnt++;
goto out;
}
}
dir = kzalloc(sizeof(*dir), GFP_KERNEL);
if (!dir)
goto out;

dir->proc_dir = proc_mkdir(sht->proc_name, proc_scsi);
if (!dir->proc_dir) {
printk(KERN_ERR "%s: proc_mkdir failed for %s\n",
__func__, sht->proc_name);
kfree(dir);
goto out;
}

dir->cnt++;
list_add_tail(&dir->list, &sht_proc_dir_list);
out:
mutex_unlock(&global_host_template_mutex);
}

and so on..

--->8---

Thanks,
John

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