netdev - RE: [PATCH] drivers/net/b44: Change to non-atomic bit operations

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Message-ID: <884d937e56ba4a91abad0d1e42cc2dd4@AcuMS.aculab.com>
Date:   Fri, 3 Jan 2020 08:47:40 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     "'Luck, Tony'" <tony.luck@...el.com>,
        Stephen Hemminger <stephen@...workplumber.org>,
        "Yu, Fenghua" <fenghua.yu@...el.com>
CC:     David Miller <davem@...emloft.net>,
        "michael.chan@...adcom.com" <michael.chan@...adcom.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "luto@...nel.org" <luto@...nel.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "Shankar, Ravi V" <ravi.v.shankar@...el.com>
Subject: RE: [PATCH] drivers/net/b44: Change to non-atomic bit operations

From: Luck, Tony
> Sent: 02 January 2020 18:23
> 
> > Why not just make pwol_pattern aligned and choose the right word to do
> > the operation on?
> 
> We use that approach for places where the operation needs to be atomic.
> 
> But this one doesn't need an atomic operation since there can be no other
> entity operating on the same bitmap in parallel.

>From what I remember this code is setting up a bitmap that is transferred
to the hardware (it might be the multicast filter).
As such it shouldn't be relying on the implementation of the bitmap
functions (which operate on long[]) to generate the required byte map
required by the hardware.

The code is horrid.

	David

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