From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-acpi-owner@vger.kernel.org>
Subject: Re: [PATCH 03/37] iommu/sva: Manage process address spaces
To: Sinan Kaya <okaya@codeaurora.org>,
        "linux-arm-kernel@lists.infradead.org"
        <linux-arm-kernel@lists.infradead.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>
Cc: "joro@8bytes.org" <joro@8bytes.org>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        Mark Rutland <Mark.Rutland@arm.com>,
        Catalin Marinas <Catalin.Marinas@arm.com>,
        Will Deacon <Will.Deacon@arm.com>,
        Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
        "hanjun.guo@linaro.org" <hanjun.guo@linaro.org>,
        Sudeep Holla <Sudeep.Holla@arm.com>,
        "rjw@rjwysocki.net" <rjw@rjwysocki.net>,
        "lenb@kernel.org" <lenb@kernel.org>,
        Robin Murphy <Robin.Murphy@arm.com>,
        "bhelgaas@google.com" <bhelgaas@google.com>,
        "alex.williamson@redhat.com" <alex.williamson@redhat.com>,
        "tn@semihalf.com" <tn@semihalf.com>,
        "liubo95@huawei.com" <liubo95@huawei.com>,
        "thunder.leizhen@huawei.com" <thunder.leizhen@huawei.com>,
        "xieyisheng1@huawei.com" <xieyisheng1@huawei.com>,
        "xuzaibo@huawei.com" <xuzaibo@huawei.com>,
        "ilias.apalodimas@linaro.org" <ilias.apalodimas@linaro.org>,
        "jonathan.cameron@huawei.com" <jonathan.cameron@huawei.com>,
        "shunyong.yang@hxt-semitech.com" <shunyong.yang@hxt-semitech.com>,
        "nwatters@codeaurora.org" <nwatters@codeaurora.org>,
        "jcrouse@codeaurora.org" <jcrouse@codeaurora.org>,
        "rfranz@cavium.com" <rfranz@cavium.com>,
        "dwmw2@infradead.org" <dwmw2@infradead.org>,
        "jacob.jun.pan@linux.intel.com" <jacob.jun.pan@linux.intel.com>,
        "yi.l.liu@intel.com" <yi.l.liu@intel.com>,
        "ashok.raj@intel.com" <ashok.raj@intel.com>,
        "robdclark@gmail.com" <robdclark@gmail.com>,
        "christian.koenig@amd.com" <christian.koenig@amd.com>,
        "bharatku@xilinx.com" <bharatku@xilinx.com>
References: <20180212183352.22730-1-jean-philippe.brucker@arm.com>
 <20180212183352.22730-4-jean-philippe.brucker@arm.com>
 <04d4d161-ed72-f6b6-9b94-1d60bd79ef94@codeaurora.org>
From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Message-ID: <f2ea5af2-dfd6-7463-0eaa-ee9ede87eac1@arm.com>
Date: Fri, 13 Apr 2018 11:59:29 +0100
MIME-Version: 1.0
In-Reply-To: <04d4d161-ed72-f6b6-9b94-1d60bd79ef94@codeaurora.org>
Content-Type: text/plain; charset=utf-8
Sender: linux-acpi-owner@vger.kernel.org
List-ID: <linux-pci.vger.kernel.org>

On 10/04/18 19:53, Sinan Kaya wrote:
> On 2/12/2018 1:33 PM, Jean-Philippe Brucker wrote:
>> +static void io_mm_detach_all_locked(struct iommu_bond *bond)
>> +{
>> +	while (!io_mm_detach_locked(bond));
>> +}
>> +
> 
> I don't remember if I mentioned this before or not but I think this loop
> needs a little bit relaxation with yield and maybe an informational message
> with might help if wait exceeds some time.

Right, at the very least we should have a cpu_relax here. I think this
bit is going away, though, because I want to lift the possibility of
calling bind() for the same dev/mm pair multiple times. It's not useful
in my opinion because that call could only be issued by a given driver.

Thanks,
Jean