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Wed, 27 Jan 2021 20:40:16 -0500 Received: from mail-wm1-x32c.google.com (mail-wm1-x32c.google.com [IPv6:2a00:1450:4864:20::32c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9D389C061574 for ; Wed, 27 Jan 2021 17:39:35 -0800 (PST) Received: by mail-wm1-x32c.google.com with SMTP id c128so3270553wme.2 for ; Wed, 27 Jan 2021 17:39:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=bD/VCVjj32VNsX3HNf6RUTS6We9z8YAWKdn/ZRhfnFk=; b=CPR//aHwcRkYpWg0dG1iMwmilRiWOfIz8Q0SeopKQFDFBXrddmR6ZoL2qcQV4wk9d9 eNlNO+LnD8dHLSNIaaTLveM5g9nXKWiaFZ5vLMuM9m68tM2CI8JjB+fj3lv1Xq98rvRP +IZBqaR1K9TmJvTwxsTnn4K9APcX+9bYI5aAttDJln1hnFY4nPHLVNCxZI8jXuu++Aza wJoe88xF4WRkJj2IV4lbB30CXGZobcp7cP73XZsW75V4mi5HQYujGZWfSy/JJYx0GdJb wQJodLylsvkZSF5H77rzUV8pO7zUQwdzTqTHnlV/NU33qeKHZ3v5pR7PfiqijR6Zy9RN /ABw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=bD/VCVjj32VNsX3HNf6RUTS6We9z8YAWKdn/ZRhfnFk=; b=fuffBuy+/lngStwLqpgQuYHOdZZrcujfpyVMmnIoAzIgLaNKqKlba3rVbq4H06Eiaj fUfbNBbktddU2X94Xp9iJUe5YGV6e0ek/EfmvK3kHmSLG/VUy87/Mw+FnngzuULsFNVO Lg5oQDKEMtJcqGvmzxXd4hclpjLV2YZJ3y4O+28uwAfXrLg0C3YnRdSXqtND2S3yE37Q v0ZGLcOliM66xMBugdpwhyeXsSCWHKvFj7oFr1VGvdo9W2aCtwspNlgawczxctvuE6ul eWCQDOax8ayBYHmwYdQ4GpESZ4b+ByaH4lHAQ6KzmnCKzfSYWsznn0CAbF45MTn7Dufi N2FA== X-Gm-Message-State: AOAM533L2FBuzGs/D6fN0ILMvoJyzpsVAy3sR5NWcZuKOK9vVSSL+nre tnKrILzS7kaMZKZlOPMfIVlNZS7E7YySqaALvwU= X-Google-Smtp-Source: ABdhPJzWHbzYC3IaCOplYSVbKv4PpN9hKZOdvRc2w2583PleTZVxhrnUhxELOb544xyyg2doSlrsQM+4oOwNiFDmtjI= X-Received: by 2002:a7b:cbd7:: with SMTP id n23mr6452368wmi.162.1611797974426; Wed, 27 Jan 2021 17:39:34 -0800 (PST) MIME-Version: 1.0 References: <20210125232023.78649-1-ljp@linux.ibm.com> <20210127170105.011ebb9b@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210127173133.1fb08b8a@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210127173133.1fb08b8a@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> From: Lijun Pan Date: Wed, 27 Jan 2021 19:39:22 -0600 Message-ID: Subject: Re: [PATCH net v2] ibmvnic: Ensure that CRQ entry read are correctly ordered To: Jakub Kicinski Cc: Lijun Pan , netdev@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Jan 27, 2021 at 7:31 PM Jakub Kicinski wrote: > > On Wed, 27 Jan 2021 19:22:25 -0600 Lijun Pan wrote: > > On Wed, Jan 27, 2021 at 7:06 PM Jakub Kicinski wrote: > > > > > > On Mon, 25 Jan 2021 17:20:23 -0600 Lijun Pan wrote: > > > > Ensure that received Command-Response Queue (CRQ) entries are > > > > properly read in order by the driver. dma_rmb barrier has > > > > been added before accessing the CRQ descriptor to ensure > > > > the entire descriptor is read before processing. > > > > > > > > Fixes: 032c5e82847a ("Driver for IBM System i/p VNIC protocol") > > > > Signed-off-by: Lijun Pan > > > > --- > > > > v2: drop dma_wmb according to Jakub's opinion > > > > > > > > drivers/net/ethernet/ibm/ibmvnic.c | 8 ++++++++ > > > > 1 file changed, 8 insertions(+) > > > > > > > > diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c > > > > index 9778c83150f1..d84369bd5fc9 100644 > > > > --- a/drivers/net/ethernet/ibm/ibmvnic.c > > > > +++ b/drivers/net/ethernet/ibm/ibmvnic.c > > > > @@ -5084,6 +5084,14 @@ static void ibmvnic_tasklet(struct tasklet_struct *t) > > > > while (!done) { > > > > /* Pull all the valid messages off the CRQ */ > > > > while ((crq = ibmvnic_next_crq(adapter)) != NULL) { > > > > + /* Ensure that the entire CRQ descriptor queue->msgs > > > > + * has been loaded before reading its contents. > > > > > > I still find this sentence confusing, maybe you mean to say stored > > > instead of loaded? > > > > The above 2 lines are the general description. The below 4 lines are > > detailed explanations. If it is still confusing, we can delete the above > > 2 lines of comments. > > Yes, I'd find the comment clearer without them, thanks. v3 has been sent out: https://patchwork.kernel.org/project/netdevbpf/patch/20210128013442.88319-1-ljp@linux.ibm.com/ Thanks, Lijun