Jason Wang
2021-Jul-16 02:57 UTC
[PATCH 1/1] virtio: disable partitions scanning for no partitions block
? 2021/7/15 ??5:47, Yury Kamenev ??:> Signed-off-by: Yury Kamenev <damtev at yandex-team.ru>I think we need a better commit log here. And why do we need a Kconfig for this? If there's a good reason, I guess the right approach is to invent something in the virtio core (via /sys)? Thanks> --- > .../admin-guide/kernel-parameters.txt | 3 +++ > drivers/block/Kconfig | 7 +++++ > drivers/block/virtio_blk.c | 26 +++++++++++++++++++ > include/uapi/linux/virtio_blk.h | 2 ++ > 4 files changed, 38 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index bdb22006f713..941bdaf5c167 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -6076,6 +6076,9 @@ > brightness level. > default: 1 > > + virtiopartscan > + Enable virtio block device partition scanning omission based on VIRTIO_BLK_F_NO_PART_SCAN feature flag. > + > virtio_mmio.device> [VMMIO] Memory mapped virtio (platform) device. > > diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig > index 63056cfd4b62..69ecd3fd7037 100644 > --- a/drivers/block/Kconfig > +++ b/drivers/block/Kconfig > @@ -399,6 +399,13 @@ config VIRTIO_BLK > This is the virtual block driver for virtio. It can be used with > QEMU based VMMs (like KVM or Xen). Say Y or M. > > +config VIRTIO_BLK_NO_PART_SCAN > + bool "Disable partition scanning for devices with no partitions" > + depends on VIRTIO_BLK > + help > + Disable partition scanning for devices with no partitions. > + Can reduce the kernel start time for tiny systems like squashfs images. > + > config BLK_DEV_RBD > tristate "Rados block device (RBD)" > depends on INET && BLOCK > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > index 4b49df2dfd23..479711d3791c 100644 > --- a/drivers/block/virtio_blk.c > +++ b/drivers/block/virtio_blk.c > @@ -692,6 +692,19 @@ static const struct blk_mq_ops virtio_mq_ops = { > static unsigned int virtblk_queue_depth; > module_param_named(queue_depth, virtblk_queue_depth, uint, 0444); > > +#ifndef MODULE > +#ifdef CONFIG_VIRTIO_BLK_NO_PART_SCAN > +static int partitions_scanning_disable __read_mostly; > + > +static int __init partitions_scanning_setup(char *__unused) > +{ > + partitions_scanning_disable = 1; > + return 1; > +} > +__setup("nopartscan", partitions_scanning_setup); > +#endif > +#endif > + > static int virtblk_probe(struct virtio_device *vdev) > { > struct virtio_blk *vblk; > @@ -790,6 +803,13 @@ static int virtblk_probe(struct virtio_device *vdev) > vblk->disk->flags |= GENHD_FL_EXT_DEVT; > vblk->index = index; > > +#ifdef CONFIG_VIRTIO_BLK_NO_PART_SCAN > + if (unlikely(partitions_scanning_disable)) > + /* disable partitions scanning if it was stated in virtio features*/ > + if (virtio_has_feature(vdev, VIRTIO_BLK_F_NO_PART_SCAN)) > + vblk->disk->flags |= GENHD_FL_NO_PART_SCAN; > +#endif > + > /* configure queue flush support */ > virtblk_update_cache_mode(vdev); > > @@ -966,6 +986,9 @@ static unsigned int features_legacy[] = { > VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, > VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, > VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES, > +#ifdef CONFIG_VIRTIO_BLK_NO_PART_SCAN > + VIRTIO_BLK_F_NO_PART_SCAN, > +#endif > } > ; > static unsigned int features[] = { > @@ -973,6 +996,9 @@ static unsigned int features[] = { > VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, > VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, > VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES, > +#ifdef CONFIG_VIRTIO_BLK_NO_PART_SCAN > + VIRTIO_BLK_F_NO_PART_SCAN, > +#endif > }; > > static struct virtio_driver virtio_blk = { > diff --git a/include/uapi/linux/virtio_blk.h b/include/uapi/linux/virtio_blk.h > index d888f013d9ff..9b381675342a 100644 > --- a/include/uapi/linux/virtio_blk.h > +++ b/include/uapi/linux/virtio_blk.h > @@ -40,6 +40,7 @@ > #define VIRTIO_BLK_F_MQ 12 /* support more than one vq */ > #define VIRTIO_BLK_F_DISCARD 13 /* DISCARD is supported */ > #define VIRTIO_BLK_F_WRITE_ZEROES 14 /* WRITE ZEROES is supported */ > +#define VIRTIO_BLK_F_NO_PART_SCAN 16 /* Disable partition scanning */ > > /* Legacy feature bits */ > #ifndef VIRTIO_BLK_NO_LEGACY > -- > 2.24.3 (Apple Git-128) >