Subject: Re: [PATCH v2] powerpc/powernv: Platform dump interface

From: Anton Blanchard <[email-masked]>
Date: Tue, 25 Mar 2014 16:52:43 +1100

Hi Vasant,

> On 02/09/2014 02:50 AM, Anton Blanchard wrote:
> >
> > Hi Vasant,
> >
> >> +static void free_dump_sg_list(struct opal_sg_list *list)
> >> +{
> >> +	struct opal_sg_list *sg1;
> >> +	while (list) {
> >> +		sg1 = list->next;
> >> +		kfree(list);
> >> +		list = sg1;
> >> +	}
> >> +	list = NULL;
> >> +}
> >> +
> >> +/*
> >> + * Build dump buffer scatter gather list
> >> + */
> >> +static struct opal_sg_list *dump_data_to_sglist(void)
> >> +{
> >> +	struct opal_sg_list *sg1, *list = NULL;
> >> +	void *addr;
> >> +	int64_t size;
> >> +
> >> +	addr = dump_record.buffer;
> >> +	size = dump_record.size;
> >> +
> >> +	sg1 = kzalloc(PAGE_SIZE, GFP_KERNEL);
> >> +	if (!sg1)
> >> +		goto nomem;
> >> +
> >> +	list = sg1;
> >> +	sg1->num_entries = 0;
> >> +	while (size > 0) {
> >> +		/* Translate virtual address to physical address
> >> */
> >> +		sg1->entry[sg1->num_entries].data =
> >> +			(void *)(vmalloc_to_pfn(addr) <<
> >> PAGE_SHIFT); +
> >> +		if (size > PAGE_SIZE)
> >> +			sg1->entry[sg1->num_entries].length =
> >> PAGE_SIZE;
> >> +		else
> >> +			sg1->entry[sg1->num_entries].length =
> >> size; +
> >> +		sg1->num_entries++;
> >> +		if (sg1->num_entries >= SG_ENTRIES_PER_NODE) {
> >> +			sg1->next = kzalloc(PAGE_SIZE,
> >> GFP_KERNEL);
> >> +			if (!sg1->next)
> >> +				goto nomem;
> >> +
> >> +			sg1 = sg1->next;
> >> +			sg1->num_entries = 0;
> >> +		}
> >> +		addr += PAGE_SIZE;
> >> +		size -= PAGE_SIZE;
> >> +	}
> >> +	return list;
> >> +
> >> +nomem:
> >> +	pr_err("%s : Failed to allocate memory\n", __func__);
> >> +	free_dump_sg_list(list);
> >> +	return NULL;
> >> +}
> >> +
> >> +/*
> >> + * Translate sg list address to absolute
> >> + */
> >> +static void sglist_to_phy_addr(struct opal_sg_list *list)
> >> +{
> >> +	struct opal_sg_list *sg, *next;
> >> +
> >> +	for (sg = list; sg; sg = next) {
> >> +		next = sg->next;
> >> +		/* Don't translate NULL pointer for last entry */
> >> +		if (sg->next)
> >> +			sg->next = (struct opal_sg_list
> >> *)__pa(sg->next);
> >> +		else
> >> +			sg->next = NULL;
> >> +
> >> +		/* Convert num_entries to length */
> >> +		sg->num_entries =
> >> +			sg->num_entries * sizeof(struct
> >> opal_sg_entry) + 16;
> >> +	}
> >> +}
> >> +
> >> +static void free_dump_data_buf(void)
> >> +{
> >> +	vfree(dump_record.buffer);
> >> +	dump_record.size = 0;
> >> +}
> >
> 
> Anton,
> 
> > This looks identical to the code in opal-flash.c. Considering how
> > complicated it is, can we put it somewhere common?
> 
> Thanks for the review.. Will look into it next week.

This doesn't appear to have been fixed in the version that went into
next.

Anton