linux-kernel - Re: [PATCH v3 03/12] powerpc/kexec_file: add helper functions for getting memory ranges

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Message-ID: <5bacae70-7a01-7d37-89fe-ea896d6ac63e@linux.ibm.com>
Date:   Fri, 17 Jul 2020 02:38:12 +0530
From:   Hari Bathini <hbathini@...ux.ibm.com>
To:     Thiago Jung Bauermann <bauerman@...ux.ibm.com>
Cc:     Pingfan Liu <piliu@...hat.com>, Nayna Jain <nayna@...ux.ibm.com>,
        Kexec-ml <kexec@...ts.infradead.org>,
        Mahesh J Salgaonkar <mahesh@...ux.ibm.com>,
        Mimi Zohar <zohar@...ux.ibm.com>,
        lkml <linux-kernel@...r.kernel.org>,
        linuxppc-dev <linuxppc-dev@...abs.org>,
        Sourabh Jain <sourabhjain@...ux.ibm.com>,
        Petr Tesarik <ptesarik@...e.cz>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Dave Young <dyoung@...hat.com>,
        Vivek Goyal <vgoyal@...hat.com>,
        Eric Biederman <ebiederm@...ssion.com>
Subject: Re: [PATCH v3 03/12] powerpc/kexec_file: add helper functions for
 getting memory ranges



On 15/07/20 5:19 am, Thiago Jung Bauermann wrote:
> 

<snip>

> <snip>
> 
>> +/**
>> + * get_mem_rngs_size - Get the allocated size of mrngs based on
>> + *                     max_nr_ranges and chunk size.
>> + * @mrngs:             Memory ranges.
>> + *
>> + * Returns the maximum no. of ranges.
> 
> This isn't correct. It returns the maximum size of @mrngs.

True. Will update..

> <snip>
> 
>> +/**
>> + * add_tce_mem_ranges - Adds tce-table range to the given memory ranges list.
>> + * @mem_ranges:         Range list to add the memory range(s) to.
>> + *
>> + * Returns 0 on success, negative errno on error.
>> + */
>> +int add_tce_mem_ranges(struct crash_mem **mem_ranges)
>> +{
>> +	struct device_node *dn;
>> +	int ret;
>> +
>> +	for_each_node_by_type(dn, "pci") {
>> +		u64 base;
>> +		u32 size;
>> +
>> +		ret = of_property_read_u64(dn, "linux,tce-base", &base);
>> +		ret |= of_property_read_u32(dn, "linux,tce-size", &size);
>> +		if (!ret)
> 
> Shouldn't the condition be `ret` instead of `!ret`?

Oops! Will fix it.

>> +/**
>> + * sort_memory_ranges - Sorts the given memory ranges list.
>> + * @mem_ranges:         Range list to sort.
>> + * @merge:              If true, merge the list after sorting.
>> + *
>> + * Returns nothing.
>> + */
>> +void sort_memory_ranges(struct crash_mem *mrngs, bool merge)
>> +{
>> +	struct crash_mem_range *rngs;
>> +	struct crash_mem_range rng;
>> +	int i, j, idx;
>> +
>> +	if (!mrngs)
>> +		return;
>> +
>> +	/* Sort the ranges in-place */
>> +	rngs = &mrngs->ranges[0];
>> +	for (i = 0; i < mrngs->nr_ranges; i++) {
>> +		idx = i;
>> +		for (j = (i + 1); j < mrngs->nr_ranges; j++) {
>> +			if (rngs[idx].start > rngs[j].start)
>> +				idx = j;
>> +		}
>> +		if (idx != i) {
>> +			rng = rngs[idx];
>> +			rngs[idx] = rngs[i];
>> +			rngs[i] = rng;
>> +		}
>> +	}
> 
> Would it work using sort() from lib/sort.c here?

Yeah. I think we could reuse it with a simple compare callback. Will do that.

Thanks
Hari