Messages in this thread Patch in this message | | | From | Fabio Aiuto <> | Subject | [PATCH v3] md: dm-init: Wait devices if it's not find on first adpet | Date | Wed, 6 Apr 2022 17:46:31 +0200 |
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From: Michael Trimarchi <michael@amarulasolutions.com>
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
Wait loop is limited to 10 at the moment for our use case showed no more than 4 loops before successfully find data device.
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com> Signed-off-by: Fabio Aiuto <fabio.aiuto@amarulasolutions.com> --- Changes from v1: - limit the loop to 10 iterations - change variable names - check only for -ENODEV failures
Changes from v2: - use a limit in seconds (not in retry number) - add a parameter - update docs
.../admin-guide/device-mapper/dm-init.rst | 13 +++++++++++ drivers/md/dm-init.c | 23 +++++++++++++++++-- 2 files changed, 34 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/device-mapper/dm-init.rst b/Documentation/admin-guide/device-mapper/dm-init.rst index e5242ff17e9b..5c2f2bf1db03 100644 --- a/Documentation/admin-guide/device-mapper/dm-init.rst +++ b/Documentation/admin-guide/device-mapper/dm-init.rst @@ -123,3 +123,16 @@ Other examples (per target): 0 1638400 verity 1 8:1 8:2 4096 4096 204800 1 sha256 fb1a5a0f00deb908d8b53cb270858975e76cf64105d412ce764225d53b8f3cfd 51934789604d1b92399c52e7cb149d1b3a1b74bbbcb103b2a0aaacbed5c08584 + +Delay for waiting deferred probes of block devices +================================================== + +Sometimes the late initcall starting the early creation of mapped +devices, starts too early. A loop waiting for probing of block +devices has been added; the default maximum delay is 1 second but +it can be set through the following kernel command:: + + dm-mod.delay=<seconds> + +This allows the procedure to retry the creation of a mapped device +after a short wait (5 msecs). diff --git a/drivers/md/dm-init.c b/drivers/md/dm-init.c index b0c45c6ebe0b..f4c5b4a46001 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 <linux/async.h> #include <linux/ctype.h> +#include <linux/delay.h> #include <linux/device.h> #include <linux/device-mapper.h> #include <linux/init.h> @@ -18,8 +20,10 @@ #define DM_MAX_DEVICES 256 #define DM_MAX_TARGETS 256 #define DM_MAX_STR_SIZE 4096 +#define DM_DEFAULT_MAX_PROBE_DELAY 1 static char *create; +static int delay = DM_DEFAULT_MAX_PROBE_DELAY; /* * Format: dm-mod.create=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+] @@ -267,6 +271,8 @@ static int __init dm_init_init(void) LIST_HEAD(devices); char *str; int r; + int loopcnt = delay * 1000 / 5; + bool devnotfound = false; if (!create) return 0; @@ -275,6 +281,7 @@ 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; @@ -287,13 +294,23 @@ static int __init dm_init_init(void) wait_for_device_probe(); list_for_each_entry(dev, &devices, list) { - if (dm_early_create(&dev->dmi, dev->table, - dev->target_args_array)) + r = dm_early_create(&dev->dmi, dev->table, dev->target_args_array); + if (r == -ENODEV) { + devnotfound = true; break; + } } + out: kfree(str); dm_setup_cleanup(&devices); + if (devnotfound && loopcnt) { + msleep(5); + devnotfound = false; + loopcnt--; + goto retry; + } + return r; } @@ -301,3 +318,5 @@ late_initcall(dm_init_init); module_param(create, charp, 0); MODULE_PARM_DESC(create, "Create a mapped device in early boot"); +module_param(delay, int, 0); +MODULE_PARM_DESC(delay, "Max delay to wait for data/hash device probe in seconds"); -- 2.30.2
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