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[68.160.176.52]) by smtp.gmail.com with ESMTPSA id de8-20020a05620a370800b0067ec34c9f27sm8282351qkb.129.2022.04.05.08.50.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Apr 2022 08:50:40 -0700 (PDT) Date: Tue, 5 Apr 2022 11:50:39 -0400 From: Mike Snitzer To: Michael Trimarchi Cc: Alasdair Kergon , dm-devel@redhat.com, linux-kernel@vger.kernel.org, Fabio Aiuto Subject: Re: [RFC PATCH] md: dm-init: Wait devices if it's not find on first adpet Message-ID: References: <20220401220705.82077-1-michael@amarulasolutions.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220401220705.82077-1-michael@amarulasolutions.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 01 2022 at 6:07P -0400, Michael Trimarchi wrote: > The device driver can be deferrable and can be a race during > the dm-init early. We need to wait all the probe are really finished > in a loop as is done in do_mounts. This is was tested on kernel 5.4 > but code seems was not changed since that time > > 003: imx8mq-usb-phy 381f0040.usb-phy: 381f0040.usb-phy supply vbus not found, using dummy regulator > 003: imx8mq-usb-phy 382f0040.usb-phy: 382f0040.usb-phy supply vbus not found, using dummy regulator > 003: imx-cpufreq-dt imx-cpufreq-dt: cpu speed grade 5 mkt segment 0 supported-hw 0x20 0x1 > 003: caam-dma caam-dma: caam dma support with 2 job rings > 000: hctosys: unable to open rtc device (rtc0) > 000: device-mapper: init: waiting for all devices to be available before creating mapped devices > 002: device-mapper: table: 254:0: verity: Data device lookup failed > 002: device-mapper: ioctl: error adding target to table > 002: crng init done > 003: of_cfs_init > 003: of_cfs_init: OK > 003: Waiting for root device /dev/dm-0... > 001: mmc2: new HS400 Enhanced strobe MMC card at address 0001 > 001: mmcblk2: mmc2:0001 IB2916 14.6 GiB > 001: mmcblk2boot0: mmc2:0001 IB2916 partition 1 4.00 MiB > 001: mmcblk2boot1: mmc2:0001 IB2916 partition 2 4.00 MiB > 001: mmcblk2rpmb: mmc2:0001 IB2916 partition 3 4.00 MiB, chardev (249:0) > 001: mmcblk2: p1 p2 p3 p4 p5 p6 p7 p8 p9 p10 p11 > 001: VSD_3V3: disabling > > with the patch > > 003: device-mapper: init: waiting for all devices to be available before creating mapped devices > > 000: device-mapper: table: 254:0: verity: Data device lookup failed > 000: device-mapper: ioctl: error adding target to table > 002: crng init done > 003: device-mapper: init: waiting for all devices to be available before creating mapped devices > 003: device-mapper: table: 254:0: verity: Data device lookup failed > 003: device-mapper: ioctl: error adding target to table > 003: device-mapper: init: waiting for all devices to be available before creating mapped devices > 000: device-mapper: table: 254:0: verity: Data device lookup failed > 000: device-mapper: ioctl: error adding target to table > 002: device-mapper: init: waiting for all devices to be available before creating mapped devices > 002: device-mapper: table: 254:0: verity: Data device lookup failed > 002: device-mapper: ioctl: error adding target to table > 000: device-mapper: init: waiting for all devices to be available before creating mapped devices > 000: device-mapper: table: 254:0: verity: Data device lookup failed > 000: device-mapper: ioctl: error adding target to table > 003: mmc2: new HS400 Enhanced strobe MMC card at address 0001 > 003: mmcblk2: mmc2:0001 DG4016 14.7 GiB > 003: mmcblk2boot0: mmc2:0001 DG4016 partition 1 4.00 MiB > 003: mmcblk2boot1: mmc2:0001 DG4016 partition 2 4.00 MiB > 003: mmcblk2rpmb: mmc2:0001 DG4016 partition 3 4.00 MiB, chardev (249:0) > 003: mmcblk2: p1 p2 p3 p4 p5 p6 p7 p8 p9 p10 p11 > 002: device-mapper: init: waiting for all devices to be available before creating mapped devices > 003: device-mapper: verity: sha256 using implementation "sha256-caam" > 000: device-mapper: ioctl: dm-0 (rootfs) is ready > > Signed-off-by: Michael Trimarchi > --- > drivers/md/dm-init.c | 15 ++++++++++++++- > 1 file changed, 14 insertions(+), 1 deletion(-) > > diff --git a/drivers/md/dm-init.c b/drivers/md/dm-init.c > index b0c45c6ebe0b..d3b754036484 100644 > --- a/drivers/md/dm-init.c > +++ b/drivers/md/dm-init.c > @@ -7,7 +7,9 @@ > * This file is released under the GPLv2. > */ > > +#include > #include > +#include > #include > #include > #include > @@ -267,6 +269,7 @@ static int __init dm_init_init(void) > LIST_HEAD(devices); > char *str; > int r; > + bool fail = false; > > if (!create) > return 0; > @@ -275,6 +278,7 @@ static int __init dm_init_init(void) > DMERR("Argument is too big. Limit is %d", DM_MAX_STR_SIZE); > return -EINVAL; > } > +retry: > str = kstrndup(create, DM_MAX_STR_SIZE, GFP_KERNEL); > if (!str) > return -ENOMEM; > @@ -288,12 +292,21 @@ static int __init dm_init_init(void) > > list_for_each_entry(dev, &devices, list) { > if (dm_early_create(&dev->dmi, dev->table, > - dev->target_args_array)) > + dev->target_args_array)) { > + fail = true; > break; > + } > } > + > out: > kfree(str); > dm_setup_cleanup(&devices); > + if (fail) { > + msleep(5); > + fail = false; > + goto retry; > + } > + > return r; > } > > -- > 2.25.1 > I'm cannot take this as proposed. If you're going to do something like this, the retries need to be bounded. And retry should only be possible for select cases (e.g. "verity: Data device lookup failed", which is emitted due to dm_get_device failure with a return -ENODEV). So please narrow this as much as possible (by only allowing retry if -ENODEV) and bound the retries to a finite amount.. 5? 10? 20? *shrug* And please take care to use variable names that are more appropriate ("fail" is not one of them when you're writing retry code) Mike