linux-kernel - Re: [PATCH] advansys: use request

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Date:	Sat, 12 Jul 2008 22:39:08 +0530
From:	Jaswinder Singh <jaswinder@...radead.org>
To:	Matthew Wilcox <matthew@....cx>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	David Woodhouse <dwmw2@...radead.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	kernel-janitors <kernel-janitors@...r.kernel.org>,
	kernelnewbies <kernelnewbies@...linux.org>,
	linux-scsi@...r.kernel.org, hch@...radead.org
Subject: Re: [PATCH] advansys: use request_firmware

Hello Mattew,

On Sat, 2008-07-12 at 10:29 -0600, Matthew Wilcox wrote:
> > +	if (AscLoadMicroCode(iop_base, 0, &fw->data[4],
> > +			     fw->size - 4) != chksum) {
> >  		asc_dvc->err_code |= ASC_IERR_MCODE_CHKSUM;
> >  		return warn_code;
> >  	}
> > +	release_firmware(fw);
> 

Sorry, It should be :-
+       if (AscLoadMicroCode(iop_base, 0, &fw->data[4],
+                            fw->size - 4) != chksum) {
                asc_dvc->err_code |= ASC_IERR_MCODE_CHKSUM;
+               release_firmware(fw);
                return warn_code;
        }
+       release_firmware(fw);
        warn_code |= AscInitMicroCodeVar(asc_dvc);

You can get updated patch from
http://git.infradead.org/users/jaswinder/firm-jsr-2.6.git 

This is first draft, final patch will available at David's firmware tree
http://git.infradead.org/users/dwmw2/firmware-2.6.git

> You're calling release_firmware() here.  I don't know if that actually
> frees the firmware when it's built-in, but if it does, then freeing the
> firmware could cause the chip to stop working if it gets reset before
> userspace is up.

Normally release_firmware will be called after loading microcode.

Even it gets reset then It will again call request_firmware and load
firmware and then frees after loading microcode.

Logically it will work same as microcode_buffer say _adv_asc3550_buf[]
when you need to load microcode you just read from _adv_asc3550_buf[]
and load it. And if reset occurs you again read from _adv_asc3550_buf[]
and then load microcode, but you keep _adv_asc3550_buf[] all the time
in memory.
In our case we just request_firmware when need to load microcode and
release_firmware after loading. So we frees the memory after loading
microcode.

So it will not stop the chip from working.

> If it is OK to call release_firmware here, then the error path is
> missing a release_firmware() call.
> 

Fixed. Thanks.

If you still have some doubts, please let me know.

Thank you,

Jaswinder Singh.

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