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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200218220746.GG7090@xz-x1> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-MC-Unique: l5QxO0DpOdSoojMW-e7xkg-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eduardo Habkost , "Michael S . Tsirkin" , "Dr . David Alan Gilbert" , qemu-devel@nongnu.org, Alex Williamson , Stefan Hajnoczi , Paolo Bonzini , Igor Mammedov , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 18.02.20 23:07, Peter Xu wrote: > On Wed, Feb 12, 2020 at 02:42:41PM +0100, David Hildenbrand wrote: >> Everybody discards the error. Let's error_report() instead so this error >> doesn't get lost. >> >> Cc: Richard Henderson >> Cc: Paolo Bonzini >> Cc: Eduardo Habkost >> Cc: Marcel Apfelbaum >> Cc: Alex Williamson >> Cc: Stefan Hajnoczi >> Signed-off-by: David Hildenbrand >=20 > IMHO error_setg() should be preferred comparing to error_report() > because it has a context to be delivered to the caller, so the error > has a better chance to be used in a better way (e.g., QMP only > supports error_setg()). Please note that I decided to go for error_report() because that's also what's being done in the matching opposite way: qemu_vfio_do_mapping(). >=20 > A better solution is that we deliver the error upper. For example, > qemu_vfio_dma_map() is one caller of qemu_vfio_undo_mapping, if you > see the callers of qemu_vfio_dma_map() you'll notice most of them has > Error** defined (e.g., nvme_init_queue). Then we can link all of them > up. Propagating errors is helpful if the caller can actually do something with the error. If it's a function that's supposed to never fail (which is the case here obviously), then there is not much benefit in doing so. >=20 > Another lazy solution (and especially if vfio-helpers are still mostly > used only by advanced users) is we can simply pass in &error_abort for > the three callers then they won't be missed... I prefer this variant, as it matches qemu_vfio_do_mapping() - except that we don't report -errno - which is fine, because the function is expected to not fail in any sane use case. Thanks! --=20 Thanks, David / dhildenb