linux-kernel - Re: [net-next v3 05/15] net: cavium/liquidio: Convert tasklet API to new bottom half workqueue mechanism

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]

Message-ID: <CAOMdWS+=5OVmtez1NPjHTMbYy9br8ciRy8nmsnaFguTKJQiD9g@mail.gmail.com>
Date: Tue, 6 Aug 2024 20:15:50 -0700
From: Allen <allen.lkml@...il.com>
To: Jakub Kicinski <kuba@...nel.org>
Cc: "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Paolo Abeni <pabeni@...hat.com>, jes@...ined-monkey.org, kda@...ux-powerpc.org, 
	cai.huoqing@...ux.dev, dougmill@...ux.ibm.com, npiggin@...il.com, 
	christophe.leroy@...roup.eu, aneesh.kumar@...nel.org, 
	naveen.n.rao@...ux.ibm.com, nnac123@...ux.ibm.com, tlfalcon@...ux.ibm.com, 
	cooldavid@...ldavid.org, marcin.s.wojtas@...il.com, mlindner@...vell.com, 
	stephen@...workplumber.org, nbd@....name, sean.wang@...iatek.com, 
	Mark-MC.Lee@...iatek.com, lorenzo@...nel.org, matthias.bgg@...il.com, 
	angelogioacchino.delregno@...labora.com, borisp@...dia.com, 
	bryan.whitehead@...rochip.com, UNGLinuxDriver@...rochip.com, 
	louis.peens@...igine.com, richardcochran@...il.com, 
	linux-rdma@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-acenic@...site.dk, linux-net-drivers@....com, netdev@...r.kernel.org, 
	Sunil Goutham <sgoutham@...vell.com>
Subject: Re: [net-next v3 05/15] net: cavium/liquidio: Convert tasklet API to
 new bottom half workqueue mechanism

> > Sure, please review the explanation below and let me
> > know if it is clear enough:
> >
> > tasklet_enable() is used to enable a tasklet, which defers
> > work to be executed in an interrupt context. It relies on the
> > tasklet mechanism for deferred execution.
> >
> > enable_and_queue_work() combines enabling the work with
> > scheduling it on a workqueue. This approach not only enables
> > the work but also schedules it for execution by the workqueue
> > system, which is more flexible and suitable for tasks needing
> > process context rather than interrupt context.
> >
> > enable_and_queue_work() internally calls enable_work() to enable
> > the work item and then uses queue_work() to add it to the workqueue.
> > This ensures that the work item is both enabled and explicitly
> > scheduled for execution within the workqueue system's context.
> >
> > As mentioned, "unconditionally scheduling the work item after
> > enable_work() returns true should work for most users." This
> > ensures that the work is consistently scheduled for execution,
> > aligning with the typical workqueue usage pattern. Most users
> > expect that enabling a work item implies it will be scheduled for
> > execution without additional conditional logic.
>
> This looks good for the explanation of the APIs, but you need to
> add another paragraph explaining why the conversion is correct
> for the given user. Basically whether the callback is safe to
> be called even if there's no work.

 Okay.

how about the following:

In the context of of the driver, the conversion from tasklet_enable()
to enable_and_queue_work() is correct because the callback function
associated with the work item is designed to be safe even if there
is no immediate work to process. The callback function can handle
being invoked in such situations without causing errors or undesirable
behavior. This makes the workqueue approach a suitable and safe
replacement for the current tasklet mechanism, as it provides the
necessary flexibility and ensures that the work item is properly
scheduled and executed.

Thanks,
Allen