From: Miklos Szeredi <miklos@szeredi.hu>
To: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
dan.j.williams@intel.com, Al Viro <viro@zeniv.linux.org.uk>,
aleksey.obitotskiy@intel.com, pawel.baldysiak@intel.com,
artur.paszkiewicz@intel.com, maksymilian.kunt@intel.com
Subject: Re: [PATCH v2][RESEND] seq_file: don't set read position for invalid iterator
Date: Thu, 24 Nov 2016 16:39:57 +0100 [thread overview]
Message-ID: <CAJfpegsywJWWo7ZBpN8=1uPyPpiDbF2XdN0WaEXcKr8YFdOAtQ@mail.gmail.com> (raw)
In-Reply-To: <20161124152342.GA9751@proton.igk.intel.com>
On Thu, Nov 24, 2016 at 4:23 PM, Tomasz Majchrzak
<tomasz.majchrzak@intel.com> wrote:
> I don't understand it. Is it possible to map file position to the index
> (record)? I think there is no way to determine record size without actually
> reading it.
Right. So don't update m->index when a zero size record is read.
This will result in m->index always pointing to the first record at
the given offset. You use this property for the single record case
and zero offset, but I'd consider behavior consistent if this was not
just done for this special case.
>> But I doubt that we actually need to do that. For example just special casing
>> the zero offset (always translating to zero index) would be conceptually simpler
>> and equivalent to your patch for the sysfs case.
>
> Do you mean such piece of code?
>
> if (ppos == 0)
> m->index = 0;
Yes. Which is a special case, but it's at least simple and easy to prove right.
Thanks,
Miklos
next prev parent reply other threads:[~2016-11-24 15:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-12 12:07 [PATCH v2][RESEND] seq_file: don't set read position for invalid iterator Tomasz Majchrzak
2016-10-26 9:17 ` Miklos Szeredi
2016-10-31 9:32 ` Tomasz Majchrzak
2016-11-02 9:11 ` Miklos Szeredi
2016-11-24 15:23 ` Tomasz Majchrzak
2016-11-24 15:39 ` Miklos Szeredi [this message]
2016-11-28 15:11 ` [PATCH v3] seq_file: reset iterator to first record for zero offset Tomasz Majchrzak
2016-11-29 9:58 ` Miklos Szeredi
2016-11-29 14:18 ` [PATCH v4] " Tomasz Majchrzak
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