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Tue, 26 Feb 2019 08:41:40 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 3gTK6PjDqmLx; Tue, 26 Feb 2019 08:41:40 +0100 (CET) Received: from PO15451 (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id BEEB88B794; Tue, 26 Feb 2019 08:41:39 +0100 (CET) Subject: Re: [PATCH 1/5] mm/resource: return real error codes from walk failures To: Dave Hansen , linux-kernel@vger.kernel.org References: <20190225185727.BCBD768C@viggo.jf.intel.com> <20190225185730.D8AA7812@viggo.jf.intel.com> From: Christophe Leroy Message-ID: <87f914ce-c9e8-7fc5-d048-702fa809013f@c-s.fr> Date: Tue, 26 Feb 2019 08:41:39 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190225185730.D8AA7812@viggo.jf.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: thomas.lendacky@amd.com, mhocko@suse.com, dave.jiang@intel.com, linux-nvdimm@lists.01.org, tiwai@suse.de, vishal.l.verma@intel.com, ying.huang@intel.com, keith.busch@intel.com, linux-mm@kvack.org, jglisse@redhat.com, fengguang.wu@intel.com, paulus@samba.org, baiyaowei@cmss.chinamobile.com, zwisler@kernel.org, bhelgaas@google.com, dan.j.williams@intel.com, bp@suse.de, linuxppc-dev@lists.ozlabs.org, akpm@linux-foundation.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Le 25/02/2019 à 19:57, Dave Hansen a écrit : > From: Dave Hansen > > walk_system_ram_range() can return an error code either becuase > *it* failed, or because the 'func' that it calls returned an > error. The memory hotplug does the following: > > ret = walk_system_ram_range(..., func); > if (ret) > return ret; > > and 'ret' makes it out to userspace, eventually. The problem > s, walk_system_ram_range() failues that result from *it* failing > (as opposed to 'func') return -1. That leads to a very odd > -EPERM (-1) return code out to userspace. > > Make walk_system_ram_range() return -EINVAL for internal > failures to keep userspace less confused. > > This return code is compatible with all the callers that I > audited. > > This changes both the generic mm/ and powerpc-specific > implementations to have the same return value. > > Signed-off-by: Dave Hansen > Reviewed-by: Bjorn Helgaas > Acked-by: Michael Ellerman (powerpc) > Cc: Dan Williams > Cc: Dave Jiang > Cc: Ross Zwisler > Cc: Vishal Verma > Cc: Tom Lendacky > Cc: Andrew Morton > Cc: Michal Hocko > Cc: linux-nvdimm@lists.01.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-mm@kvack.org > Cc: Huang Ying > Cc: Fengguang Wu > Cc: Borislav Petkov > Cc: Yaowei Bai > Cc: Takashi Iwai > Cc: Jerome Glisse > Cc: Benjamin Herrenschmidt > Cc: Paul Mackerras > Cc: linuxppc-dev@lists.ozlabs.org > Cc: Keith Busch > --- > > b/arch/powerpc/mm/mem.c | 2 +- walk_system_ram_range() was droped in commit https://git.kernel.orghttps://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=26b523356f49a0117c8f9e32ca98aa6d6e496e1a Christophe > b/kernel/resource.c | 4 ++-- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff -puN arch/powerpc/mm/mem.c~memory-hotplug-walk_system_ram_range-returns-neg-1 arch/powerpc/mm/mem.c > --- a/arch/powerpc/mm/mem.c~memory-hotplug-walk_system_ram_range-returns-neg-1 2019-02-25 10:56:47.452908034 -0800 > +++ b/arch/powerpc/mm/mem.c 2019-02-25 10:56:47.458908034 -0800 > @@ -189,7 +189,7 @@ walk_system_ram_range(unsigned long star > struct memblock_region *reg; > unsigned long end_pfn = start_pfn + nr_pages; > unsigned long tstart, tend; > - int ret = -1; > + int ret = -EINVAL; > > for_each_memblock(memory, reg) { > tstart = max(start_pfn, memblock_region_memory_base_pfn(reg)); > diff -puN kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 kernel/resource.c > --- a/kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 2019-02-25 10:56:47.454908034 -0800 > +++ b/kernel/resource.c 2019-02-25 10:56:47.459908034 -0800 > @@ -382,7 +382,7 @@ static int __walk_iomem_res_desc(resourc > int (*func)(struct resource *, void *)) > { > struct resource res; > - int ret = -1; > + int ret = -EINVAL; > > while (start < end && > !find_next_iomem_res(start, end, flags, desc, first_lvl, &res)) { > @@ -462,7 +462,7 @@ int walk_system_ram_range(unsigned long > unsigned long flags; > struct resource res; > unsigned long pfn, end_pfn; > - int ret = -1; > + int ret = -EINVAL; > > start = (u64) start_pfn << PAGE_SHIFT; > end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; > _ >