netdev - Re: [PATCH 13/15] devlink: support directly reading from region memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 31 Jan 2020 11:15:39 -0800
From:   Jacob Keller <jacob.e.keller@...el.com>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     netdev@...r.kernel.org, jiri@...nulli.us, valex@...lanox.com,
        linyunsheng@...wei.com, lihong.yang@...el.com
Subject: Re: [PATCH 13/15] devlink: support directly reading from region
 memory

On 1/31/2020 10:07 AM, Jakub Kicinski wrote:
> On Thu, 30 Jan 2020 14:59:08 -0800, Jacob Keller wrote:
>> +static int devlink_nl_region_read_direct_fill(struct sk_buff *skb,
>> +					      struct devlink *devlink,
>> +					      struct devlink_region *region,
>> +					      struct nlattr **attrs,
>> +					      u64 start_offset,
>> +					      u64 end_offset,
>> +					      bool dump,
>> +					      u64 *new_offset)
>> +{
>> +	u64 curr_offset = start_offset;
>> +	int err = 0;
>> +	u8 *data;
>> +
>> +	/* Allocate and re-use a single buffer */
>> +	data = kzalloc(DEVLINK_REGION_READ_CHUNK_SIZE, GFP_KERNEL);
>> +	if (!data)
>> +		return -ENOMEM;
>> +
>> +	*new_offset = start_offset;
>> +
>> +	if (end_offset > region->size || dump)
>> +		end_offset = region->size;
>> +
>> +	while (curr_offset < end_offset) {
>> +		u32 data_size;
>> +
>> +		if (end_offset - curr_offset < DEVLINK_REGION_READ_CHUNK_SIZE)
>> +			data_size = end_offset - curr_offset;
>> +		else
>> +			data_size = DEVLINK_REGION_READ_CHUNK_SIZE;
> 
> Also known as min() ?

This was more or less adapted from the read_snapshot_fill function. I
could probably make more of an effort to share this logic.

Thanks,
Jake