On Thu, Nov 24 2022 at 5:35P -0500, Peter Korsgaard <peter@xxxxxxxxxxxxx> wrote: > >>>>> "Peter" == Peter Korsgaard <peter@xxxxxxxxxxxxx> writes: > > > Just calling wait_for_device_probe() is not enough to ensure that > > asynchronously probed block devices are available (E.G. mmc, usb, ..), so > > add a "dm-mod.waitfor=<device1>[,..,<deviceN>]" parameter to get dm-init to > > explicitly wait for specific block devices before initializing the tables > > with logic similar to the rootwait logic in init/do_mounts.c. > > > E.G. with dm-verity on mmc with > > dm-mod.waitfor="PARTLABEL=hash-a,PARTLABEL=root-a" > > > [ 0.671671] device-mapper: init: waiting for all devices to be available before creating mapped devices > > [ 0.671679] device-mapper: init: waiting for PARTLABEL=hash-a > > [ 0.710695] mmc0: new HS200 MMC card at address 0001 > > [ 0.711158] mmcblk0: mmc0:0001 004GA0 3.69 GiB > > [ 0.715954] mmcblk0boot0: mmc0:0001 004GA0 partition 1 2.00 MiB > > [ 0.722085] mmcblk0boot1: mmc0:0001 004GA0 partition 2 2.00 MiB > > [ 0.728093] mmcblk0rpmb: mmc0:0001 004GA0 partition 3 512 KiB, chardev (249:0) > > [ 0.738274] mmcblk0: p1 p2 p3 p4 p5 p6 p7 > > [ 0.751282] device-mapper: init: waiting for PARTLABEL=root-a > > [ 0.751306] device-mapper: init: all devices available > > [ 0.751683] device-mapper: verity: sha256 using implementation "sha256-generic" > > [ 0.759344] device-mapper: ioctl: dm-0 (vroot) is ready > > [ 0.766540] VFS: Mounted root (squashfs filesystem) readonly on device 254:0. > > > Signed-off-by: Peter Korsgaard <peter@xxxxxxxxxxxxx> > > --- > > Changes since v1: > > - Fix s/dm-init/dm-mod/ typo in documentation, drop trailing newline > > Ping? > > FYI: I was recently made aware that other patches fixing this issue > (but less nice, E.G. with a fixed delay) have been posted in the past, > so there seems to be a general need for something like this. > > E.G: > https://lore.kernel.org/all/20220406154631.277107-1-fabio.aiuto@xxxxxxxxxxxxxxxxxxxx/ > > > > > .../admin-guide/device-mapper/dm-init.rst | 8 +++++++ > > drivers/md/dm-init.c | 23 ++++++++++++++++++- > > 2 files changed, 30 insertions(+), 1 deletion(-) > > > diff --git a/Documentation/admin-guide/device-mapper/dm-init.rst b/Documentation/admin-guide/device-mapper/dm-init.rst > > index e5242ff17e9b..981d6a907699 100644 > > --- a/Documentation/admin-guide/device-mapper/dm-init.rst > > +++ b/Documentation/admin-guide/device-mapper/dm-init.rst > > @@ -123,3 +123,11 @@ Other examples (per target): > > 0 1638400 verity 1 8:1 8:2 4096 4096 204800 1 sha256 > > fb1a5a0f00deb908d8b53cb270858975e76cf64105d412ce764225d53b8f3cfd > > 51934789604d1b92399c52e7cb149d1b3a1b74bbbcb103b2a0aaacbed5c08584 > > + > > +For setups using device-mapper on top of asynchronously probed block > > +devices (MMC, USB, ..), it may be necessary to tell dm-init to > > +explicitly wait for them to become available before setting up the > > +device-mapper tables. This can be done with the "dm-mod.waitfor=" > > +module parameter, which takes a list of devices to wait for:: > > + > > + dm-mod.waitfor=<device1>[,..,<deviceN>] > > diff --git a/drivers/md/dm-init.c b/drivers/md/dm-init.c > > index b0c45c6ebe0b..fc70b568e072 100644 > > --- a/drivers/md/dm-init.c > > +++ b/drivers/md/dm-init.c > > @@ -8,6 +8,7 @@ > > */ > > > #include <linux/ctype.h> > > +#include <linux/delay.h> > > #include <linux/device.h> > > #include <linux/device-mapper.h> > > #include <linux/init.h> > > @@ -18,12 +19,17 @@ > > #define DM_MAX_DEVICES 256 > > #define DM_MAX_TARGETS 256 > > #define DM_MAX_STR_SIZE 4096 > > +#define DM_MAX_WAITFOR 256 > > > static char *create; > > > +static char *waitfor[DM_MAX_WAITFOR]; > > + > > /* > > * Format: dm-mod.create=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+] > > * Table format: <start_sector> <num_sectors> <target_type> <target_args> > > + * Block devices to wait for to become available before setting up tables: > > + * dm-mod.waitfor=<device1>[,..,<deviceN>] > > * > > * See Documentation/admin-guide/device-mapper/dm-init.rst for dm-mod.create="..." format > > * details. > > @@ -266,7 +272,7 @@ static int __init dm_init_init(void) > > struct dm_device *dev; > > LIST_HEAD(devices); > > char *str; > > - int r; > > + int i, r; > > > if (!create) > > return 0; > > @@ -286,6 +292,18 @@ static int __init dm_init_init(void) > > DMINFO("waiting for all devices to be available before creating mapped devices"); > > wait_for_device_probe(); > > > + for (i = 0; i < ARRAY_SIZE(waitfor); i++) { > > + if (waitfor[i]) { > > + DMINFO("waiting for %s", waitfor[i]); > > + > > + while (!dm_get_dev_t(waitfor[i])) > > + msleep(20); > > + } > > + } > > + > > + if (waitfor[0]) > > + DMINFO("all devices available"); > > + Why 20? Also, why is waiting indefinitely OK? Would really like to hear from other consumers of dm-init that this module param is useful and needed. Mike > > list_for_each_entry(dev, &devices, list) { > > if (dm_early_create(&dev->dmi, dev->table, > dev-> target_args_array)) > > @@ -301,3 +319,6 @@ late_initcall(dm_init_init); > > > module_param(create, charp, 0); > > MODULE_PARM_DESC(create, "Create a mapped device in early boot"); > > + > > +module_param_array(waitfor, charp, NULL, 0); > > +MODULE_PARM_DESC(waitfor, "Devices to wait for before setting up tables"); > > -- > > > 2.30.2 > > > -- > Bye, Peter Korsgaard > -- dm-devel mailing list dm-devel@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/dm-devel
