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Fri, 08 Aug 2025 11:01:33 -0700 (PDT) X-Relaying-Domain: purestorage.com Received: from dev-ushankar.dev.purestorage.com (dev-ushankar.dev.purestorage.com [10.7.70.36]) by c7-smtp-2023.dev.purestorage.com (Postfix) with ESMTP id 66C8E340235; Fri, 8 Aug 2025 12:01:32 -0600 (MDT) Received: by dev-ushankar.dev.purestorage.com (Postfix, from userid 1557716368) id 57299E4018A; Fri, 8 Aug 2025 12:01:32 -0600 (MDT) Date: Fri, 8 Aug 2025 12:01:32 -0600 From: Uday Shankar To: Caleb Sander Mateos Cc: Ming Lei , Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ublk: check for unprivileged daemon on each I/O fetch Message-ID: References: <20250808155216.296170-1-csander@purestorage.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250808155216.296170-1-csander@purestorage.com> On Fri, Aug 08, 2025 at 09:52:15AM -0600, Caleb Sander Mateos wrote: > Commit ab03a61c6614 ("ublk: have a per-io daemon instead of a per-queue > daemon") allowed each ublk I/O to have an independent daemon task. > However, nr_privileged_daemon is only computed based on whether the last > I/O fetched in each ublk queue has an unprivileged daemon task. > Fix this by checking whether every fetched I/O's daemon is privileged. > Change nr_privileged_daemon from a count of queues to a boolean > indicating whether any I/Os have an unprivileged daemon. > > Signed-off-by: Caleb Sander Mateos > Fixes: ab03a61c6614 ("ublk: have a per-io daemon instead of a per-queue daemon") Nice catch! > --- > drivers/block/ublk_drv.c | 16 +++++++--------- > 1 file changed, 7 insertions(+), 9 deletions(-) > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > index 6561d2a561fa..a035070dd690 100644 > --- a/drivers/block/ublk_drv.c > +++ b/drivers/block/ublk_drv.c > @@ -233,11 +233,11 @@ struct ublk_device { > > struct ublk_params params; > > struct completion completion; > unsigned int nr_queues_ready; > - unsigned int nr_privileged_daemon; > + bool unprivileged_daemons; > struct mutex cancel_mutex; > bool canceling; > pid_t ublksrv_tgid; > }; > > @@ -1548,11 +1548,11 @@ static void ublk_reset_ch_dev(struct ublk_device *ub) > ublk_queue_reinit(ub, ublk_get_queue(ub, i)); > > /* set to NULL, otherwise new tasks cannot mmap io_cmd_buf */ > ub->mm = NULL; > ub->nr_queues_ready = 0; > - ub->nr_privileged_daemon = 0; > + ub->unprivileged_daemons = false; > ub->ublksrv_tgid = -1; > } > > static struct gendisk *ublk_get_disk(struct ublk_device *ub) > { > @@ -1978,16 +1978,14 @@ static void ublk_reset_io_flags(struct ublk_device *ub) > /* device can only be started after all IOs are ready */ > static void ublk_mark_io_ready(struct ublk_device *ub, struct ublk_queue *ubq) > __must_hold(&ub->mutex) > { > ubq->nr_io_ready++; > - if (ublk_queue_ready(ubq)) { > + if (ublk_queue_ready(ubq)) > ub->nr_queues_ready++; > - > - if (capable(CAP_SYS_ADMIN)) > - ub->nr_privileged_daemon++; > - } > + if (!ub->unprivileged_daemons && !capable(CAP_SYS_ADMIN)) > + ub->unprivileged_daemons = true; Shorter: ub->unprivileged_daemons |= !capable(CAP_SYS_ADMIN); > > if (ub->nr_queues_ready == ub->dev_info.nr_hw_queues) { > /* now we are ready for handling ublk io request */ > ublk_reset_io_flags(ub); > complete_all(&ub->completion); > @@ -2878,12 +2876,12 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, > ub->dev_info.ublksrv_pid = ublksrv_pid; > ub->ub_disk = disk; > > ublk_apply_params(ub); > > - /* don't probe partitions if any one ubq daemon is un-trusted */ > - if (ub->nr_privileged_daemon != ub->nr_queues_ready) > + /* don't probe partitions if any daemon task is un-trusted */ > + if (ub->unprivileged_daemons) > set_bit(GD_SUPPRESS_PART_SCAN, &disk->state); > > ublk_get_device(ub); > ub->dev_info.state = UBLK_S_DEV_LIVE; > > -- > 2.45.2 >