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From: Seiji Aguchi <seiji.aguchi@hds.com>
To: Mike Waychison <mikew@google.com>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Luck, Tony (tony.luck@intel.com)" <tony.luck@intel.com>,
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	<dle-develop@lists.sourceforge.net>,
        Satoru Moriya <satoru.moriya@hds.com>
Subject: RE: efi_pstore: question about how to remove create_sysfs_entry()
 from a write callback.
Thread-Topic: efi_pstore: question about how to remove create_sysfs_entry()
 from a write callback.
Thread-Index: Ac16Npmt6jTfpP4+SGO2J5V3Hs4KkwAMhuYAAAddZ3AADOaFoP//i5WAgAA2n/A=
Date: Tue, 14 Aug 2012 21:38:20 +0000
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> 
> Something like this (pseudo) may work:
> 
> /* Loop until we have all entries in efivars. */ while (1) {
>   variable_name = kzalloc(1024, GFP_KERNEL );
>   spin_lock_irqsave(&efivars->lock);
>   bool found = false;
>   while (1) {
>      ret = ops->get_next_variable(variable_name)
>      if (ret == EFI_NOT_FOUND)
>         break;
>      if (!variable_is_already_present(variable, &efivars->list) {
>        found = true;
>        break;
>      }
>   }
>   if (!found) {
>     kfree(variable_name);
>     break;
>   }
>   <Register in sysfs>
> }
> 

Thanks. It seems to work.
I will create a patch based on your pseudo code above.

> 
> If we are calling into pstore_info ops though from interrupt context, it seems we'll need to fix the immediate problem of updating the
> locking throughout to be interrupt safe.
> 

I agree with you. It should be fixing.  I will update the locking to be interrupt safe as well.

Seiji
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