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[156.34.55.100]) by smtp.gmail.com with ESMTPSA id v184sm1061841qkd.85.2019.06.06.08.57.19 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 06 Jun 2019 08:57:20 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1hYulT-0005QQ-Ix; Thu, 06 Jun 2019 12:57:19 -0300 Date: Thu, 6 Jun 2019 12:57:19 -0300 From: Jason Gunthorpe To: rcampbell@nvidia.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, John Hubbard , Ira Weiny , Dan Williams , Arnd Bergmann , Balbir Singh , Dan Carpenter , Matthew Wilcox , Souptick Joarder , Andrew Morton Subject: Re: [PATCH 2/5] mm/hmm: Clean up some coding style and comments Message-ID: <20190606155719.GA8896@ziepe.ca> References: <20190506232942.12623-1-rcampbell@nvidia.com> <20190506232942.12623-3-rcampbell@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190506232942.12623-3-rcampbell@nvidia.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 06, 2019 at 04:29:39PM -0700, rcampbell@nvidia.com wrote: > @@ -924,6 +922,7 @@ int hmm_range_register(struct hmm_range *range, > unsigned page_shift) > { > unsigned long mask = ((1UL << page_shift) - 1UL); > + struct hmm *hmm; > > range->valid = false; > range->hmm = NULL; I was finishing these patches off and noticed that 'hmm' above is never initialized. I added the below to this patch: diff --git a/mm/hmm.c b/mm/hmm.c index 678873eb21930a..8e7403f081f44a 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -932,19 +932,20 @@ int hmm_range_register(struct hmm_range *range, range->start = start; range->end = end; - range->hmm = hmm_get_or_create(mm); - if (!range->hmm) + hmm = hmm_get_or_create(mm); + if (!hmm) return -EFAULT; /* Check if hmm_mm_destroy() was call. */ - if (range->hmm->mm == NULL || range->hmm->dead) { - hmm_put(range->hmm); + if (hmm->mm == NULL || hmm->dead) { + hmm_put(hmm); return -EFAULT; } /* Initialize range to track CPU page table updates. */ - mutex_lock(&range->hmm->lock); + mutex_lock(&hmm->lock); + range->hmm = hmm; list_add_rcu(&range->list, &hmm->ranges); /* Which I think was the intent of adding the 'struct hmm *'. I prefer this arrangement as it does not set an leave an invalid hmm pointer in the range if there is a failure.. Most probably the later patches fixed this up? Please confirm, thanks Regards, Jason