From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Battersby Subject: Re: [PATCH v2 2/9] dmapool: cleanup error messages Date: Fri, 3 Aug 2018 13:03:17 -0400 Message-ID: References: <7a943124-c65e-f0ed-cc5c-20b23f021505@cybernetics.com> <20180803162212.GA4718@bombadil.infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <20180803162212.GA4718-PfSpb0PWhxZc2C7mugBRk2EX/6BAtgUQ@public.gmane.org> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Matthew Wilcox , Andy Shevchenko Cc: linux-scsi , Chaitra P B , Suganath Prabu Subramani , Sathya Prakash , linux-mm , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, MPT-FusionLinux.pdl-dY08KVG/lbpWk0Htik3J/w@public.gmane.org, Christoph Hellwig List-Id: linux-scsi@vger.kernel.org T24gMDgvMDMvMjAxOCAxMjoyMiBQTSwgTWF0dGhldyBXaWxjb3ggd3JvdGU6Cj4gT24gRnJpLCBB dWcgMDMsIDIwMTggYXQgMDY6NTk6MjBQTSArMDMwMCwgQW5keSBTaGV2Y2hlbmtvIHdyb3RlOgo+ Pj4+PiBJJ20gcHJldHR5IHN1cmUgdGhpcyB3YXMgY3JlYXRlZCBpbiBhbiBvcmRlciB0byBhdm9p ZCBiYWQgbG9va2luZyAoYW5kCj4+Pj4+IGluIHNvbWUgY2FzZXMgZnJpZ2h0ZW5pbmcpICJOVUxM IGRldmljZSAqIiBwYXJ0Lgo+PiBKRllJOiBnaXQgbG9nIC0tbm8tbWVyZ2VzIC0tZ3JlcCAnTlVM TCBkZXZpY2UgXConCj4gSSB0aGluayB0aG9zZSBjb21taXRzIGFjdHVhbGx5IGFyZ3VlIGluIGZh dm91ciBvZiBUb255J3MgcGF0Y2ggdG8gcmVtb3ZlCj4gdGhlIHNwZWNpYWwgY2FzaW5nLiAgSXMg aXQgcmVhbGx5IHVzZWZ1bCB0byBjcmVhdGUgZG1hIHBvb2xzIHdpdGggYSBOVUxMCj4gZGV2aWNl Pwo+Cj4KZG1hX2FsbG9jX2NvaGVyZW50KCkgZG9lcyBhcHBlYXIgdG8gc3VwcG9ydCBhIE5VTEwg ZGV2LCBzbyBpdCBtaWdodCBtYWtlCnNlbnNlIGluIHRoZW9yeS7CoCBCdXQgSSBjYW4ndCBmaW5k IGFueSBpbi10cmVlIGNhbGxlcnMgdGhhdCBhY3R1YWxseQpwYXNzIGEgTlVMTCBkZXYgdG8gZG1h X3Bvb2xfY3JlYXRlKCkuwqAgU28gZm9yIG9uZSBvZiB0aGUgZHJlYWRlZCAoTlVMTApkZXZpY2Ug KikgbWVzc2FnZXMgdG8gc2hvdyB1cCwgaXQgd291bGQgdGFrZSBib3RoIGEgbmV3IGNhbGxlciB0 aGF0CnBhc3NlcyBhIE5VTEwgZGV2IHRvIGRtYV9wb29sX2NyZWF0ZSgpIGFuZCBhIGJ1ZyB0byBj YXVzZSB0aGUgbWVzc2FnZSB0bwpiZSBwcmludGVkLsKgIElzIHRoYXQgd29ydGggdGhlIHNwZWNp YWwgY2FzaW5nPwoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X18KaW9tbXUgbWFpbGluZyBsaXN0CmlvbW11QGxpc3RzLmxpbnV4LWZvdW5kYXRpb24ub3JnCmh0 dHBzOi8vbGlzdHMubGludXhmb3VuZGF0aW9uLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2lvbW11 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id A794A6B000D for ; Fri, 3 Aug 2018 13:03:21 -0400 (EDT) Received: by mail-qt0-f197.google.com with SMTP id b8-v6so4727824qto.16 for ; Fri, 03 Aug 2018 10:03:21 -0700 (PDT) Received: from mail.cybernetics.com (mail.cybernetics.com. [173.71.130.66]) by mx.google.com with ESMTPS id n83-v6si600994qki.267.2018.08.03.10.03.20 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 03 Aug 2018 10:03:20 -0700 (PDT) Subject: Re: [PATCH v2 2/9] dmapool: cleanup error messages References: <7a943124-c65e-f0ed-cc5c-20b23f021505@cybernetics.com> <20180803162212.GA4718@bombadil.infradead.org> From: Tony Battersby Message-ID: Date: Fri, 3 Aug 2018 13:03:17 -0400 MIME-Version: 1.0 In-Reply-To: <20180803162212.GA4718@bombadil.infradead.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: Matthew Wilcox , Andy Shevchenko Cc: Christoph Hellwig , Marek Szyprowski , Sathya Prakash , Chaitra P B , Suganath Prabu Subramani , iommu@lists.linux-foundation.org, linux-mm , linux-scsi , MPT-FusionLinux.pdl@broadcom.com On 08/03/2018 12:22 PM, Matthew Wilcox wrote: > On Fri, Aug 03, 2018 at 06:59:20PM +0300, Andy Shevchenko wrote: >>>>> I'm pretty sure this was created in an order to avoid bad looking (and >>>>> in some cases frightening) "NULL device *" part. >> JFYI: git log --no-merges --grep 'NULL device \*' > I think those commits actually argue in favour of Tony's patch to remove > the special casing. Is it really useful to create dma pools with a NULL > device? > > dma_alloc_coherent() does appear to support a NULL dev, so it might make sense in theory.A But I can't find any in-tree callers that actually pass a NULL dev to dma_pool_create().A So for one of the dreaded (NULL device *) messages to show up, it would take both a new caller that passes a NULL dev to dma_pool_create() and a bug to cause the message to be printed.A Is that worth the special casing?