lkml.org 
[lkml]   [2021]   [Dec]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v3 3/3] blk-crypto: show crypto capabilities in sysfs
On Thu, Dec 09, 2021 at 04:02:07PM -0800, Bart Van Assche wrote:
> On 12/9/21 3:40 PM, Eric Biggers wrote:
> > On Thu, Dec 09, 2021 at 02:51:59PM -0800, Bart Van Assche wrote:
> > > Has it been considered to report each value separately, e.g. 512\n4096\n
> > > instead of 0x1200\n? I think the former approach is more friendly for shell
> > > scripts.
> >
> > I don't think that would be acceptable to the sysfs folks, as they only allow
> > one value per file. I suppose a bitmask could be viewed as unacceptable too,
> > but it seemed to make sense here, given that the data unit sizes are always
> > powers of 2, and the hardware reports them as bitmasks.
>
> In case Greg wouldn't have the time to reply, I think the following quote from
> Documentation/filesystems/sysfs.txt is relevant in this context: "Attributes
> should be ASCII text files, preferably with only one value per file. It is
> noted that it may not be efficient to contain only one value per file, so it is
> socially acceptable to express an array of values of the same type."
>
> Thanks,

It should be, but I thought that Greg had complained about people doing that
before, and required strictly one value per file. So we would need his opinion.

Note that a bitmask isn't hard to handle in a shell script:

mask=$(</sys/block/sda/queue/crypto/modes/AES-256-XTS)
if (( mask & 4096 )); then
echo "4096-byte data units supported"
fi

But I could see how someone could prefer something like

if grep -q '\<4096\>' /sys/block/sda/queue/crypto/modes/AES-256-XTS; then
echo "4096-byte data units supported"
fi

- Eric

\
 
 \ /
  Last update: 2021-12-10 01:13    [W:0.085 / U:0.192 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site