linux-stable.git/include/linux/genhd.h, branch v5.6.2

block: Fix partition support for host aware zoned block devices

2020-03-12T13:54:39+00:00

Commit b72053072c0b ("block: allow partitions on host aware zone
devices") introduced the helper function disk_has_partitions() to check
if a given disk has valid partitions. However, since this function result
directly depends on the disk partition table length rather than the
actual existence of valid partitions in the table, it returns true even
after all partitions are removed from the disk. For host aware zoned
block devices, this results in zone management support to be kept
disabled even after removing all partitions.

Fix this by changing disk_has_partitions() to walk through the partition
table entries and return true if and only if a valid non-zero size
partition is found.

Fixes: b72053072c0b ("block: allow partitions on host aware zone devices")
Cc: stable@vger.kernel.org # 5.5
Reviewed-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Shin'ichiro Kawasaki 
Signed-off-by: Jens Axboe

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-01-28T18:07:09+00:00

Pull scheduler updates from Ingo Molnar:
 "These were the main changes in this cycle:

   - More -rt motivated separation of CONFIG_PREEMPT and
     CONFIG_PREEMPTION.

   - Add more low level scheduling topology sanity checks and warnings
     to filter out nonsensical topologies that break scheduling.

   - Extend uclamp constraints to influence wakeup CPU placement

   - Make the RT scheduler more aware of asymmetric topologies and CPU
     capacities, via uclamp metrics, if CONFIG_UCLAMP_TASK=y

   - Make idle CPU selection more consistent

   - Various fixes, smaller cleanups, updates and enhancements - please
     see the git log for details"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (58 commits)
  sched/fair: Define sched_idle_cpu() only for SMP configurations
  sched/topology: Assert non-NUMA topology masks don't (partially) overlap
  idle: fix spelling mistake "iterrupts" -> "interrupts"
  sched/fair: Remove redundant call to cpufreq_update_util()
  sched/psi: create /proc/pressure and /proc/pressure/{io|memory|cpu} only when psi enabled
  sched/fair: Fix sgc->{min,max}_capacity calculation for SD_OVERLAP
  sched/fair: calculate delta runnable load only when it's needed
  sched/cputime: move rq parameter in irqtime_account_process_tick
  stop_machine: Make stop_cpus() static
  sched/debug: Reset watchdog on all CPUs while processing sysrq-t
  sched/core: Fix size of rq::uclamp initialization
  sched/uclamp: Fix a bug in propagating uclamp value in new cgroups
  sched/fair: Load balance aggressively for SCHED_IDLE CPUs
  sched/fair : Improve update_sd_pick_busiest for spare capacity case
  watchdog: Remove soft_lockup_hrtimer_cnt and related code
  sched/rt: Make RT capacity-aware
  sched/fair: Make EAS wakeup placement consider uclamp restrictions
  sched/fair: Make task_fits_capacity() consider uclamp restrictions
  sched/uclamp: Rename uclamp_util_with() into uclamp_rq_util_with()
  sched/uclamp: Make uclamp util helpers use and return UL values
  ...

block: allow partitions on host aware zone devices

2020-01-26T16:59:08+00:00

Host-aware SMR drives can be used with the commands to explicitly manage
zone state, but they can also be used as normal disks.  In the former
case it makes perfect sense to allow partitions on them, in the latter
it does not, just like for host managed devices.  Add a check to
add_partition to allow partitions on host aware devices, but give
up any zone management capabilities in that case, which also catches
the previously missed case of adding a partition vs just scanning it.

Because sd can rescan the attribute at runtime it needs to check if
a disk has partitions, for which a new helper is added to genhd.h.

Fixes: 5eac3eb30c9a ("block: Remove partition support for zoned block devices")
Reported-by: Borislav Petkov 
Signed-off-by: Christoph Hellwig 
Tested-by: Damien Le Moal 
Reviewed-by: Damien Le Moal 
Signed-off-by: Jens Axboe

sched/rt, fs: Use CONFIG_PREEMPTION

2019-12-08T13:37:36+00:00

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Switch the i_size() and part_nr_sects_…() code over to use
CONFIG_PREEMPTION. Update the comment for fsstack_copy_inode_size() also
to refer to CONFIG_PREEMPTION.

[bigeasy: +PREEMPT comments]

Signed-off-by: Thomas Gleixner 
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Thomas Gleixner 
Cc: Alexander Viro 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20191015191821.11479-24-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar

block: fix bdev_disk_changed for non-partitioned devices

2019-11-14T14:43:53+00:00

We still have to set the capacity to 0 if invalidating or call
revalidate_disk if not even if the disk has no partitions.  Fix
that by merging rescan_partitions into bdev_disk_changed and just
stubbing out blk_add_partitions and blk_drop_partitions for
non-partitioned devices.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Signed-off-by: Jens Axboe

block: move rescan_partitions to fs/block_dev.c

2019-11-14T14:43:21+00:00

Large parts of rescan_partitions aren't about partitions, and
moving it to block_dev.c will allow for some further cleanups by
merging it into its only caller.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Signed-off-by: Jens Axboe

block: merge invalidate_partitions into rescan_partitions

2019-11-14T14:42:41+00:00

A lot of the logic in invalidate_partitions and rescan_partitions is
shared.  Merge the two functions to simplify things.  There is a small
behavior change in that we now send the kevent change notice also if we
were not invalidating but no partitions were found, which seems like
the right thing to do.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Signed-off-by: Jens Axboe

block: fix use-after-free on gendisk

2019-04-22T15:48:12+00:00

commit 2da78092dda "block: Fix dev_t minor allocation lifetime"
specifically moved blk_free_devt(dev->devt) call to part_release()
to avoid reallocating device number before the device is fully
shutdown.

However, it can cause use-after-free on gendisk in get_gendisk().
We use md device as example to show the race scenes:

Process1		Worker			Process2
md_free
						blkdev_open
del_gendisk
  add delete_partition_work_fn() to wq
  						__blkdev_get
						get_gendisk
put_disk
  disk_release
    kfree(disk)
    						find part from ext_devt_idr
						get_disk_and_module(disk)
    					  	cause use after free

    			delete_partition_work_fn
			put_device(part)
    		  	part_release
		    	remove part from ext_devt_idr

Before  is removed from ext_devt_idr by
delete_partition_work_fn(), we can find the devt and then access
gendisk by hd_struct pointer. But, if we access the gendisk after
it have been freed, it can cause in use-after-freeon gendisk in
get_gendisk().

We fix this by adding a new helper blk_invalidate_devt() in
delete_partition() and del_gendisk(). It replaces hd_struct
pointer in idr with value 'NULL', and deletes the entry from
idr in part_release() as we do now.

Thanks to Jan Kara for providing the solution and more clear comments
for the code.

Fixes: 2da78092dda1 ("block: Fix dev_t minor allocation lifetime")
Cc: Al Viro 
Reviewed-by: Bart Van Assche 
Reviewed-by: Keith Busch 
Reviewed-by: Jan Kara 
Suggested-by: Jan Kara 
Signed-off-by: Yufen Yu 
Signed-off-by: Jens Axboe

block: disk_events: introduce event flags

2019-04-12T19:35:24+00:00

Currently, an empty disk->events field tells the block layer not to
forward media change events to user space. This was done in commit
7c88a168da80 ("block: don't propagate unlisted DISK_EVENTs to userland")
in order to avoid events from "fringe" drivers to be forwarded to user
space. By doing so, the block layer lost the information which events
were supported by a particular block device, and most importantly,
whether or not a given device supports media change events at all.

Prepare for not interpreting the "events" field this way in the future
any more. This is done by adding an additional field "event_flags" to
struct gendisk, and two flag bits that can be set to have the device
treated like one that had the "events" field set to a non-zero value
before. This applies only to the sd and sr drivers, which are changed to
set the new flags.

The new flags are DISK_EVENT_FLAG_POLL to enforce polling of the device
for synchronous events, and DISK_EVENT_FLAG_UEVENT to tell the
blocklayer to generate udev events from kernel events.

In order to add the event_flags field to struct gendisk, the events
field is converted to an "unsigned short"; it doesn't need to hold
values bigger than 2 anyway.

This patch doesn't change behavior.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Martin Wilck 
Signed-off-by: Jens Axboe

block: genhd: remove async_events field

2019-04-12T19:35:22+00:00

The async_events field, intended to be used for drivers that support
asynchronous notifications about disk events (aka media change events),
isn't currently used by any driver, and apparently that has been that
way for a long time (if not forever). Remove it.

Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Martin Wilck 
Signed-off-by: Jens Axboe