Commit Graph

915918 Commits

Author SHA1 Message Date
Christoph Hellwig 9353848c65 dasd: refactor dasd_ioctl_information
Prepare for in-kernel callers of this functionality.

Signed-off-by: Christoph Hellwig <hch@lst.de>
[sth@de.ibm.com: remove leftover kfree]
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:22:20 -06:00
Martijn Coenen 3448914e8c loop: Add LOOP_CONFIGURE ioctl
This allows userspace to completely setup a loop device with a single
ioctl, removing the in-between state where the device can be partially
configured - eg the loop device has a backing file associated with it,
but is reading from the wrong offset.

Besides removing the intermediate state, another big benefit of this
ioctl is that LOOP_SET_STATUS can be slow; the main reason for this
slowness is that LOOP_SET_STATUS(64) calls blk_mq_freeze_queue() to
freeze the associated queue; this requires waiting for RCU
synchronization, which I've measured can take about 15-20ms on this
device on average.

In addition to doing what LOOP_SET_STATUS can do, LOOP_CONFIGURE can
also be used to:
- Set the correct block size immediately by setting
  loop_config.block_size (avoids LOOP_SET_BLOCK_SIZE)
- Explicitly request direct I/O mode by setting LO_FLAGS_DIRECT_IO
  in loop_config.info.lo_flags (avoids LOOP_SET_DIRECT_IO)
- Explicitly request read-only mode by setting LO_FLAGS_READ_ONLY
  in loop_config.info.lo_flags

Here's setting up ~70 regular loop devices with an offset on an x86
Android device, using LOOP_SET_FD and LOOP_SET_STATUS:

vsoc_x86:/system/apex # time for i in `seq 30 100`;
do losetup -r -o 4096 /dev/block/loop$i com.android.adbd.apex; done
    0m03.40s real     0m00.02s user     0m00.03s system

Here's configuring ~70 devices in the same way, but using a modified
losetup that uses the new LOOP_CONFIGURE ioctl:

vsoc_x86:/system/apex # time for i in `seq 30 100`;
do losetup -r -o 4096 /dev/block/loop$i com.android.adbd.apex; done
    0m01.94s real     0m00.01s user     0m00.01s system

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:35 -06:00
Martijn Coenen faf1d25440 loop: Clean up LOOP_SET_STATUS lo_flags handling
LOOP_SET_STATUS(64) will actually allow some lo_flags to be modified; in
particular, LO_FLAGS_AUTOCLEAR can be set and cleared, whereas
LO_FLAGS_PARTSCAN can be set to request a partition scan. Make this
explicit by updating the UAPI to include the flags that can be
set/cleared using this ioctl.

The implementation can then blindly take over the passed in flags,
and use the previous flags for those flags that can't be set / cleared
using LOOP_SET_STATUS.

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:35 -06:00
Martijn Coenen 571fae6e29 loop: Rework lo_ioctl() __user argument casting
In preparation for a new ioctl that needs to copy_from_user(); makes the
code easier to read as well.

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:35 -06:00
Martijn Coenen 62ab466ca8 loop: Move loop_set_status_from_info() and friends up
So we can use it without forward declaration. This is a separate commit
to make it easier to verify that this is just a move, without functional
modifications.

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:35 -06:00
Martijn Coenen 0c3796c244 loop: Factor out configuring loop from status
Factor out this code into a separate function, so it can be reused by
other code more easily.

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:34 -06:00
Martijn Coenen 0a6ed1b5ff loop: Remove figure_loop_size()
This function was now only used by loop_set_capacity(). Just open code
the remaining code in the caller instead.

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:34 -06:00
Martijn Coenen b0bd158dd6 loop: Refactor loop_set_status() size calculation
figure_loop_size() calculates the loop size based on the passed in
parameters, but at the same time it updates the offset and sizelimit
parameters in the loop device configuration. That is a somewhat
unexpected side effect of a function with this name, and it is only only
needed by one of the two callers of this function - loop_set_status().

Move the lo_offset and lo_sizelimit assignment back into loop_set_status(),
and use the newly factored out functions to validate and apply the newly
calculated size. This allows us to get rid of figure_loop_size() in a
follow-up commit.

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:34 -06:00
Martijn Coenen 716ad0986c loop: Switch to set_capacity_revalidate_and_notify()
This was recently added to block/genhd.c, and takes care of both
updating the capacity and notifying userspace of the new size.

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:34 -06:00
Martijn Coenen 5795b6f560 loop: Factor out setting loop device size
This code is used repeatedly.

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:34 -06:00
Martijn Coenen 083a6a5078 loop: Remove sector_t truncation checks
sector_t is now always u64, so we don't need to check for truncation.

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:34 -06:00
Martijn Coenen 7c5014b098 loop: Call loop_config_discard() only after new config is applied
loop_set_status() calls loop_config_discard() to configure discard for
the loop device; however, the discard configuration depends on whether
the loop device uses encryption, and when we call it the encryption
configuration has not been updated yet. Move the call down so we apply
the correct discard configuration based on the new configuration.

Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-21 08:20:34 -06:00
Xu Wang c65165651d block/swim3: use set_current_state macro
Use set_current_state macro instead of current->state = TASK_RUNNING.

Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-16 14:28:37 -06:00
Jens Axboe 8fd2b980a2 Merge branch 'md-next' of git://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-5.8/drivers
Pull MD changes from Song.

* 'md-next' of git://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md/raid1: Replace zero-length array with flexible-array
  md: add a newline when printing parameter 'start_ro' by sysfs
  md: stop using ->queuedata
  md/raid1: release pending accounting for an I/O only after write-behind is also finished
  md: remove redundant memalloc scope API usage
  raid5: update code comment of scribble_alloc()
  raid5: remove gfp flags from scribble_alloc()
  md: use memalloc scope APIs in mddev_suspend()/mddev_resume()
  md: remove the extra line for ->hot_add_disk
  md: flush md_rdev_misc_wq for HOT_ADD_DISK case
  md: don't flush workqueue unconditionally in md_open
  md: add new workqueue for delete rdev
  md: add checkings before flush md_misc_wq
2020-05-13 15:17:01 -06:00
Gustavo A. R. Silva 358369f03a md/raid1: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 12:02:23 -07:00
Xiongfeng Wang 3f99980c8f md: add a newline when printing parameter 'start_ro' by sysfs
Add a missing newline when printing module parameter 'start_ro' by
sysfs.

Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:49:19 -07:00
Christoph Hellwig e4fc5a7429 md: stop using ->queuedata
Pointer to mddev is already available in private_data.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:48:28 -07:00
David Jeffery c91114c2b8 md/raid1: release pending accounting for an I/O only after write-behind is also finished
When using RAID1 and write-behind, md can deadlock when errors occur. With
write-behind, r1bio structs can be accounted by raid1 as queued but not
counted as pending. The pending count is dropped when the original bio is
returned complete but write-behind for the r1bio may still be active.

This breaks the accounting used in some conditions to know when the raid1
md device has reached an idle state. It can result in calls to
freeze_array deadlocking. freeze_array will never complete from a negative
"unqueued" value being calculated due to a queued count larger than the
pending count.

To properly account for write-behind, move the call to allow_barrier from
call_bio_endio to raid_end_bio_io. When using write-behind, md can call
call_bio_endio before all write-behind I/O is complete. Using
raid_end_bio_io for the point to call allow_barrier will release the
pending count at a point where all I/O for an r1bio, even write-behind, is
done.

Signed-off-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:22:31 -07:00
Coly Li 3024ba2d6c md: remove redundant memalloc scope API usage
In mddev_create_serial_pool(), memalloc scope APIs memalloc_noio_save()
and memalloc_noio_restore() are used when allocating memory by calling
mempool_create_kmalloc_pool(). After adding the memalloc scope APIs in
raid array suspend context, it is unncessary to explicitly call them
around mempool_create_kmalloc_pool() any longer.

This patch removes the redundant memalloc scope APIs in
mddev_create_serial_pool().

Signed-off-by: Coly Li <colyli@suse.de>
Cc: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:22:31 -07:00
Coly Li 7f8a30e5d2 raid5: update code comment of scribble_alloc()
Code comments of scribble_alloc() is outdated for a while. This patch
update the comments in function header for the new parameter list.

Suggested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:22:31 -07:00
Coly Li ba54d4d4d2 raid5: remove gfp flags from scribble_alloc()
Using GFP_NOIO flag to call scribble_alloc() from resize_chunk() does
not have the expected behavior. kvmalloc_array() inside scribble_alloc()
which receives the GFP_NOIO flag will eventually call kmalloc_node() to
allocate physically continuous pages.

Now we have memalloc scope APIs in mddev_suspend()/mddev_resume() to
prevent memory reclaim I/Os during raid array suspend context, calling
to kvmalloc_array() with GFP_KERNEL flag may avoid deadlock of recursive
I/O as expected.

This patch removes the useless gfp flags from parameters list of
scribble_alloc(), and call kvmalloc_array() with GFP_KERNEL flag. The
incorrect GFP_NOIO flag does not exist anymore.

Fixes: b330e6a49d ("md: convert to kvmalloc")
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:22:31 -07:00
Coly Li 78f57ef9d5 md: use memalloc scope APIs in mddev_suspend()/mddev_resume()
In raid5.c:resize_chunk(), scribble_alloc() is called with GFP_NOIO
flag, then it is sent into kvmalloc_array() inside scribble_alloc().

The problem is kvmalloc_array() eventually calls kvmalloc_node() which
does not accept non GFP_KERNEL compatible flag like GFP_NOIO, then
kmalloc_node() is called indeed to allocate physically continuous
pages. When system memory is under heavy pressure, and the requesting
size is large, there is high probability that allocating continueous
pages will fail.

But simply using GFP_KERNEL flag to call kvmalloc_array() is also
progblematic. In the code path where scribble_alloc() is called, the
raid array is suspended, if kvmalloc_node() triggers memory reclaim I/Os
and such I/Os go back to the suspend raid array, deadlock will happen.

What is desired here is to allocate non-physically (a.k.a virtually)
continuous pages and avoid memory reclaim I/Os. Michal Hocko suggests
to use the mmealloc sceope APIs to restrict memory reclaim I/O in
allocating context, specifically to call memalloc_noio_save() when
suspend the raid array and to call memalloc_noio_restore() when
resume the raid array.

This patch adds the memalloc scope APIs in mddev_suspend() and
mddev_resume(), to restrict memory reclaim I/Os during the raid array
is suspended. The benifit of adding the memalloc scope API in the
unified entry point mddev_suspend()/mddev_resume() is, no matter which
md raid array type (personality), we are sure the deadlock by recursive
memory reclaim I/O won't happen on the suspending context.

Please notice that the memalloc scope APIs only take effect on the raid
array suspending context, if the memory allocation is from another new
created kthread after raid array suspended, the recursive memory reclaim
I/Os won't be restricted. The mddev_suspend()/mddev_resume() entries are
used for the critical section where the raid metadata is modifying,
creating a kthread to allocate memory inside the critical section is
queer and very probably being buggy.

Fixes: b330e6a49d ("md: convert to kvmalloc")
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:22:31 -07:00
Guoqing Jiang 3f79cc2234 md: remove the extra line for ->hot_add_disk
It is not not necessary to add a newline for them since they don't exceed
80 characters, and it is not intutive to distinguish ->hot_add_disk() from
hot_add_disk() too.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:22:31 -07:00
Guoqing Jiang 78b990cf28 md: flush md_rdev_misc_wq for HOT_ADD_DISK case
Since rdev->kobj is removed asynchronously, it is possible that the
rdev->kobj still exists when try to add the rdev again after rdev
is removed. But this path md_ioctl (HOT_ADD_DISK) -> hot_add_disk
-> bind_rdev_to_array missed it.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:22:31 -07:00
Guoqing Jiang f6766ff6af md: don't flush workqueue unconditionally in md_open
We need to check mddev->del_work before flush workqueu since the purpose
of flush is to ensure the previous md is disappeared. Otherwise the similar
deadlock appeared if LOCKDEP is enabled, it is due to md_open holds the
bdev->bd_mutex before flush workqueue.

kernel: [  154.522645] ======================================================
kernel: [  154.522647] WARNING: possible circular locking dependency detected
kernel: [  154.522650] 5.6.0-rc7-lp151.27-default #25 Tainted: G           O
kernel: [  154.522651] ------------------------------------------------------
kernel: [  154.522653] mdadm/2482 is trying to acquire lock:
kernel: [  154.522655] ffff888078529128 ((wq_completion)md_misc){+.+.}, at: flush_workqueue+0x84/0x4b0
kernel: [  154.522673]
kernel: [  154.522673] but task is already holding lock:
kernel: [  154.522675] ffff88804efa9338 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x79/0x590
kernel: [  154.522691]
kernel: [  154.522691] which lock already depends on the new lock.
kernel: [  154.522691]
kernel: [  154.522694]
kernel: [  154.522694] the existing dependency chain (in reverse order) is:
kernel: [  154.522696]
kernel: [  154.522696] -> #4 (&bdev->bd_mutex){+.+.}:
kernel: [  154.522704]        __mutex_lock+0x87/0x950
kernel: [  154.522706]        __blkdev_get+0x79/0x590
kernel: [  154.522708]        blkdev_get+0x65/0x140
kernel: [  154.522709]        blkdev_get_by_dev+0x2f/0x40
kernel: [  154.522716]        lock_rdev+0x3d/0x90 [md_mod]
kernel: [  154.522719]        md_import_device+0xd6/0x1b0 [md_mod]
kernel: [  154.522723]        new_dev_store+0x15e/0x210 [md_mod]
kernel: [  154.522728]        md_attr_store+0x7a/0xc0 [md_mod]
kernel: [  154.522732]        kernfs_fop_write+0x117/0x1b0
kernel: [  154.522735]        vfs_write+0xad/0x1a0
kernel: [  154.522737]        ksys_write+0xa4/0xe0
kernel: [  154.522745]        do_syscall_64+0x64/0x2b0
kernel: [  154.522748]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [  154.522749]
kernel: [  154.522749] -> #3 (&mddev->reconfig_mutex){+.+.}:
kernel: [  154.522752]        __mutex_lock+0x87/0x950
kernel: [  154.522756]        new_dev_store+0xc9/0x210 [md_mod]
kernel: [  154.522759]        md_attr_store+0x7a/0xc0 [md_mod]
kernel: [  154.522761]        kernfs_fop_write+0x117/0x1b0
kernel: [  154.522763]        vfs_write+0xad/0x1a0
kernel: [  154.522765]        ksys_write+0xa4/0xe0
kernel: [  154.522767]        do_syscall_64+0x64/0x2b0
kernel: [  154.522769]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [  154.522770]
kernel: [  154.522770] -> #2 (kn->count#253){++++}:
kernel: [  154.522775]        __kernfs_remove+0x253/0x2c0
kernel: [  154.522778]        kernfs_remove+0x1f/0x30
kernel: [  154.522780]        kobject_del+0x28/0x60
kernel: [  154.522783]        mddev_delayed_delete+0x24/0x30 [md_mod]
kernel: [  154.522786]        process_one_work+0x2a7/0x5f0
kernel: [  154.522788]        worker_thread+0x2d/0x3d0
kernel: [  154.522793]        kthread+0x117/0x130
kernel: [  154.522795]        ret_from_fork+0x3a/0x50
kernel: [  154.522796]
kernel: [  154.522796] -> #1 ((work_completion)(&mddev->del_work)){+.+.}:
kernel: [  154.522800]        process_one_work+0x27e/0x5f0
kernel: [  154.522802]        worker_thread+0x2d/0x3d0
kernel: [  154.522804]        kthread+0x117/0x130
kernel: [  154.522806]        ret_from_fork+0x3a/0x50
kernel: [  154.522807]
kernel: [  154.522807] -> #0 ((wq_completion)md_misc){+.+.}:
kernel: [  154.522813]        __lock_acquire+0x1392/0x1690
kernel: [  154.522816]        lock_acquire+0xb4/0x1a0
kernel: [  154.522818]        flush_workqueue+0xab/0x4b0
kernel: [  154.522821]        md_open+0xb6/0xc0 [md_mod]
kernel: [  154.522823]        __blkdev_get+0xea/0x590
kernel: [  154.522825]        blkdev_get+0x65/0x140
kernel: [  154.522828]        do_dentry_open+0x1d1/0x380
kernel: [  154.522831]        path_openat+0x567/0xcc0
kernel: [  154.522834]        do_filp_open+0x9b/0x110
kernel: [  154.522836]        do_sys_openat2+0x201/0x2a0
kernel: [  154.522838]        do_sys_open+0x57/0x80
kernel: [  154.522840]        do_syscall_64+0x64/0x2b0
kernel: [  154.522842]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [  154.522844]
kernel: [  154.522844] other info that might help us debug this:
kernel: [  154.522844]
kernel: [  154.522846] Chain exists of:
kernel: [  154.522846]   (wq_completion)md_misc --> &mddev->reconfig_mutex --> &bdev->bd_mutex
kernel: [  154.522846]
kernel: [  154.522850]  Possible unsafe locking scenario:
kernel: [  154.522850]
kernel: [  154.522852]        CPU0                    CPU1
kernel: [  154.522853]        ----                    ----
kernel: [  154.522854]   lock(&bdev->bd_mutex);
kernel: [  154.522856]                                lock(&mddev->reconfig_mutex);
kernel: [  154.522858]                                lock(&bdev->bd_mutex);
kernel: [  154.522860]   lock((wq_completion)md_misc);
kernel: [  154.522861]
kernel: [  154.522861]  *** DEADLOCK ***
kernel: [  154.522861]
kernel: [  154.522864] 1 lock held by mdadm/2482:
kernel: [  154.522865]  #0: ffff88804efa9338 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x79/0x590
kernel: [  154.522868]
kernel: [  154.522868] stack backtrace:
kernel: [  154.522873] CPU: 1 PID: 2482 Comm: mdadm Tainted: G           O      5.6.0-rc7-lp151.27-default #25
kernel: [  154.522875] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
kernel: [  154.522878] Call Trace:
kernel: [  154.522881]  dump_stack+0x8f/0xcb
kernel: [  154.522884]  check_noncircular+0x194/0x1b0
kernel: [  154.522888]  ? __lock_acquire+0x1392/0x1690
kernel: [  154.522890]  __lock_acquire+0x1392/0x1690
kernel: [  154.522893]  lock_acquire+0xb4/0x1a0
kernel: [  154.522895]  ? flush_workqueue+0x84/0x4b0
kernel: [  154.522898]  flush_workqueue+0xab/0x4b0
kernel: [  154.522900]  ? flush_workqueue+0x84/0x4b0
kernel: [  154.522905]  ? md_open+0xb6/0xc0 [md_mod]
kernel: [  154.522908]  md_open+0xb6/0xc0 [md_mod]
kernel: [  154.522910]  __blkdev_get+0xea/0x590
kernel: [  154.522912]  ? bd_acquire+0xc0/0xc0
kernel: [  154.522914]  blkdev_get+0x65/0x140
kernel: [  154.522916]  ? bd_acquire+0xc0/0xc0
kernel: [  154.522918]  do_dentry_open+0x1d1/0x380
kernel: [  154.522921]  path_openat+0x567/0xcc0
kernel: [  154.522923]  ? __lock_acquire+0x380/0x1690
kernel: [  154.522926]  do_filp_open+0x9b/0x110
kernel: [  154.522929]  ? __alloc_fd+0xe5/0x1f0
kernel: [  154.522935]  ? kmem_cache_alloc+0x28c/0x630
kernel: [  154.522939]  ? do_sys_openat2+0x201/0x2a0
kernel: [  154.522941]  do_sys_openat2+0x201/0x2a0
kernel: [  154.522944]  do_sys_open+0x57/0x80
kernel: [  154.522946]  do_syscall_64+0x64/0x2b0
kernel: [  154.522948]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [  154.522951] RIP: 0033:0x7f98d279d9ae

And md_alloc also flushed the same workqueue, but the thing is different
here. Because all the paths call md_alloc don't hold bdev->bd_mutex, and
the flush is necessary to avoid race condition, so leave it as it is.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:22:31 -07:00
Guoqing Jiang cc1ffe61c0 md: add new workqueue for delete rdev
Since the purpose of call flush_workqueue in new_dev_store is to ensure
md_delayed_delete() has completed, so we should check rdev->del_work is
pending or not.

To suppress lockdep warning, we have to check mddev->del_work while
md_delayed_delete is attached to rdev->del_work, so it is not aligned
to the purpose of flush workquee. So a new workqueue is needed to avoid
the awkward situation, and introduce a new func flush_rdev_wq to flush
the new workqueue after check if there was pending work.

Also like new_dev_store, ADD_NEW_DISK ioctl has the same purpose to flush
workqueue while it holds bdev->bd_mutex, so make the same change applies
to the ioctl to avoid similar lock issue.

And md_delayed_delete actually wants to delete rdev, so rename the function
to rdev_delayed_delete.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:22:31 -07:00
Guoqing Jiang 21e0958ec9 md: add checkings before flush md_misc_wq
Coly reported possible circular locking dependencyi with LOCKDEP enabled,
quote the below info from the detailed report [1].

[ 1607.673903] Chain exists of:
[ 1607.673903]   kn->count#256 --> (wq_completion)md_misc -->
(work_completion)(&rdev->del_work)
[ 1607.673903]
[ 1607.827946]  Possible unsafe locking scenario:
[ 1607.827946]
[ 1607.898780]        CPU0                    CPU1
[ 1607.952980]        ----                    ----
[ 1608.007173]   lock((work_completion)(&rdev->del_work));
[ 1608.069690]                                lock((wq_completion)md_misc);
[ 1608.149887]                                lock((work_completion)(&rdev->del_work));
[ 1608.242563]   lock(kn->count#256);
[ 1608.283238]
[ 1608.283238]  *** DEADLOCK ***
[ 1608.283238]
[ 1608.354078] 2 locks held by kworker/5:0/843:
[ 1608.405152]  #0: ffff8889eecc9948 ((wq_completion)md_misc){+.+.}, at:
process_one_work+0x42b/0xb30
[ 1608.512399]  #1: ffff888a1d3b7e10
((work_completion)(&rdev->del_work)){+.+.}, at: process_one_work+0x42b/0xb30
[ 1608.632130]

Since works (rdev->del_work and mddev->del_work) are queued in md_misc_wq,
then lockdep_map lock is held if either of them are running, then both of
them try to hold kernfs lock by call kobject_del. Then if new_dev_store
or array_state_store are triggered by write to the related sysfs node, so
the write operation gets kernfs lock, but need the lockdep_map because all
of them would trigger flush_workqueue(md_misc_wq) finally, then the same
lockdep_map lock is needed.

To suppress the lockdep warnning, we should flush the workqueue in case the
related work is pending. And several works are attached to md_misc_wq, so
we need to check which work should be checked:

1. for __md_stop_writes, the purpose of call flush workqueue is ensure sync
thread is started if it was starting, so check mddev->del_work is pending
or not since md_start_sync is attached to mddev->del_work.

2. __md_stop flushes md_misc_wq to ensure event_work is done, check the
event_work is enough. Assume raid_{ctr,dtr} -> md_stop -> __md_stop doesn't
need the kernfs lock.

3. both new_dev_store (holds kernfs lock) and ADD_NEW_DISK ioctl (holds the
bdev->bd_mutex) call flush_workqueue to ensure md_delayed_delete has
completed, this case will be handled in next patch.

4. md_open flushes workqueue to ensure the previous md is disappeared, but
it holds bdev->bd_mutex then try to flush workqueue, so it is better to
check mddev->del_work as well to avoid potential lock issue, this will be
done in another patch.

[1]: https://marc.info/?l=linux-raid&m=158518958031584&w=2

Cc: Coly Li <colyli@suse.de>
Reported-by: Coly Li <colyli@suse.de>
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2020-05-13 11:22:30 -07:00
Jens Axboe 91bf5ec342 Floppy patches for 5.8
Cleanups:
   - symbolic register names for x86,sparc64,sparc32,powerpc,parisc,m68k
   - split of local/global variables for drive,fdc
   - UBSAN warning suppress in setup_rw_floppy()
 
 Changes were compile tested on arm, sparc64, powerpc, m68k. Many patches
 introduce no binary changes by using defines instead of magic numbers.
 The patches were also tested with syzkaller and simple write/read/format
 tests on real hardware.
 
 Signed-off-by: Denis Efremov <efremov@linux.com>
 -----BEGIN PGP SIGNATURE-----
 
 iQJGBAABCAAwFiEEdlQDNgKUDfGSD+QDtSKVsDNQMB8FAl6626QSHGVmcmVtb3ZA
 bGludXguY29tAAoJELUilbAzUDAfLmcQAKRYCm6kjUFR37Wv1vs20LpL21J7GEg/
 sM4mBRBcbDRbBZJ0uSDaed7bSyMD7mALMuOd4O5lFOsmG31fI2WCrlHScKJoZn/U
 1+TOTbO7rYZNCw91rwYlt8qimsi1DN1i6+Lo+BTOJcTR/v/CxZ2YWxDsw9QeNQBH
 7281d2fNQA2hYsVO2sKxT2x7Cx2oWrQ6Lwno1J5OTUBRnrL3rV1CISBv+Nt53gml
 N5YZUcnb/5FzKeR9sphP07oa1G3xbCoF/bzNkHGaT8eE4tO4Nge+dlBRrKoxGp6H
 ZdeIE6JMVS3rCbzKSeorXpWzH77GBnOPYDaMROW9b+D0Unl4maanENQV6GUN7Xo+
 8eDyMrkWU1uLBmNKGUCHz4FEr3s4jAMSTfGDjYGlQ32IzbdSddSlr72AhUoIXt1o
 o2G5mix26md1XtTCdrzqTajD0WojiTv+36rsBnrziFFq38RwObCJTaos3a+8tJwf
 VfWh83ymtMGfSAbiEUT+ahedxbA3TQNJ1XvVb8ph4ckQAn9/IN0W5AU+8oWhM6Iv
 AQrknCdKU9SkTwKycDooP7ysUf+rUBbFnzyTjuF0nJAA3yZsi5h0JFIqYM1DgKUp
 5dBQnDGavxY3ZZVDXdrexBBrvvgXAObwiiXddbnsuNcowTWJZNak0FRzRIlDRNBj
 koKvWx47q/kJ
 =Pkvi
 -----END PGP SIGNATURE-----

Merge tag 'floppy-for-5.8' of https://github.com/evdenis/linux-floppy into for-5.8/drivers

Floppy patches for 5.8

Cleanups:
  - symbolic register names for x86,sparc64,sparc32,powerpc,parisc,m68k
  - split of local/global variables for drive,fdc
  - UBSAN warning suppress in setup_rw_floppy()

Changes were compile tested on arm, sparc64, powerpc, m68k. Many patches
introduce no binary changes by using defines instead of magic numbers.
The patches were also tested with syzkaller and simple write/read/format
tests on real hardware.

Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

* tag 'floppy-for-5.8' of https://github.com/evdenis/linux-floppy: (31 commits)
  floppy: suppress UBSAN warning in setup_rw_floppy()
  floppy: add defines for sizes of cmd & reply buffers of floppy_raw_cmd
  floppy: add FD_AUTODETECT_SIZE define for struct floppy_drive_params
  floppy: use print_hex_dump() in setup_DMA()
  floppy: cleanup: make set_fdc() always set current_drive and current_fd
  floppy: cleanup: get rid of current_reqD in favor of current_drive
  floppy: make sure to reset all FDCs upon resume()
  floppy: cleanup: do not iterate on current_fdc in do_floppy_init()
  floppy: cleanup: add a few comments about expectations in certain functions
  floppy: cleanup: do not iterate on current_fdc in DMA grab/release functions
  floppy: cleanup: make get_fdc_version() not rely on current_fdc anymore
  floppy: cleanup: make next_valid_format() not rely on current_drive anymore
  floppy: cleanup: make check_wp() not rely on current_{fdc,drive} anymore
  floppy: cleanup: make fdc_specify() not rely on current_{fdc,drive} anymore
  floppy: cleanup: make fdc_configure() not rely on current_fdc anymore
  floppy: cleanup: make perpendicular_mode() not rely on current_fdc anymore
  floppy: cleanup: make need_more_output() not rely on current_fdc anymore
  floppy: cleanup: make result() not rely on current_fdc anymore
  floppy: cleanup: make output_byte() not rely on current_fdc anymore
  floppy: cleanup: make wait_til_ready() not rely on current_fdc anymore
  ...
2020-05-12 11:35:49 -06:00
Denis Efremov 0836275df4 floppy: suppress UBSAN warning in setup_rw_floppy()
UBSAN: array-index-out-of-bounds in drivers/block/floppy.c:1521:45
index 16 is out of range for type 'unsigned char [16]'
Call Trace:
...
 setup_rw_floppy+0x5c3/0x7f0
 floppy_ready+0x2be/0x13b0
 process_one_work+0x2c1/0x5d0
 worker_thread+0x56/0x5e0
 kthread+0x122/0x170
 ret_from_fork+0x35/0x40

From include/uapi/linux/fd.h:
struct floppy_raw_cmd {
	...
	unsigned char cmd_count;
	unsigned char cmd[16];
	unsigned char reply_count;
	unsigned char reply[16];
	...
}

This out-of-bounds access is intentional. The command in struct
floppy_raw_cmd may take up the space initially intended for the reply
and the reply count. It is needed for long 82078 commands such as
RESTORE, which takes 17 command bytes. Initial cmd size is not enough
and since struct setup_rw_floppy is a part of uapi we check that
cmd_count is in [0:16+1+16] in raw_cmd_copyin().

The patch adds union with original cmd,reply_count,reply fields and
fullcmd field of equivalent size. The cmd accesses are turned to
fullcmd where appropriate to suppress UBSAN warning.

Link: https://lore.kernel.org/r/20200501134416.72248-5-efremov@linux.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:57 +03:00
Denis Efremov bd10a5f3e2 floppy: add defines for sizes of cmd & reply buffers of floppy_raw_cmd
Use FD_RAW_CMD_SIZE, FD_RAW_REPLY_SIZE defines instead of magic numbers
for cmd & reply buffers of struct floppy_raw_cmd. Remove local to
floppy.c MAX_REPLIES define, as it is now FD_RAW_REPLY_SIZE.
FD_RAW_CMD_FULLSIZE added as we allow command to also fill reply_count
and reply fields.

Link: https://lore.kernel.org/r/20200501134416.72248-4-efremov@linux.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:56 +03:00
Denis Efremov 9c4c5a24c8 floppy: add FD_AUTODETECT_SIZE define for struct floppy_drive_params
Use FD_AUTODETECT_SIZE for autodetect buffer size in struct
floppy_drive_params instead of a magic number.

Link: https://lore.kernel.org/r/20200501134416.72248-3-efremov@linux.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:56 +03:00
Denis Efremov 29ac67633c floppy: use print_hex_dump() in setup_DMA()
Remove pr_cont() and use print_hex_dump() in setup_DMA() to print the
contents of the cmd buffer.

Link: https://lore.kernel.org/r/20200501134416.72248-2-efremov@linux.com
Suggested-by: Joe Perches <joe@perches.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:56 +03:00
Willy Tarreau ca1b409a3b floppy: cleanup: make set_fdc() always set current_drive and current_fd
When called with a negative drive value, set_fdc() would stick to the
current fdc (which was assumed to reflect the current_drive's FDC). We
do not need this anymore as the last call place with a negative value
was just addressed. Let's make this function always set both current_fdc
and current_drive so that there's no more ambiguity. A few comments
stating this were added to a few non-obvious places.

Link: https://lore.kernel.org/r/20200410101904.14652-3-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:56 +03:00
Willy Tarreau 99ba6ccc7f floppy: cleanup: get rid of current_reqD in favor of current_drive
This macro equals -1 and is used as an alternative for current_drive when
calling reschedule_timeout(), which in turn needs to remap it. This only
adds obfuscation, let's simply use current_drive.

Link: https://lore.kernel.org/r/20200410101904.14652-2-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:56 +03:00
Willy Tarreau 6111a4f9bb floppy: make sure to reset all FDCs upon resume()
In floppy_resume() we don't properly reinitialize all FDCs, instead
we reinitialize the current FDC once per available FDC because value
-1 is passed to user_reset_fdc(). Let's simply save the current drive
and properly reinitialize each FDC.

Link: https://lore.kernel.org/r/20200410101904.14652-1-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:56 +03:00
Willy Tarreau 05f5e319a1 floppy: cleanup: do not iterate on current_fdc in do_floppy_init()
There's no need to iterate on current_fdc in do_floppy_init() anymore,
in the first case it's only used as an array index to access fdc_state[],
so let's get rid of this confusing assignment. The second case is a bit
trickier because user_reset_fdc() needs to already know current_fdc when
called with drive==-1 due to this call chain:

    user_reset_fdc()
      lock_fdc()
        set_fdc()
           drive<0 ==> new_fdc = current_fdc

Note that current_drive is not used in this code part and may even not
match a unit belonging to current_fdc. Instead of passing -1 we can
simply pass the first drive of the FDC being initialized, which is even
cleaner as it will allow the function chain above to consistently assign
both variables.

Link: https://lore.kernel.org/r/20200410093023.14499-1-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:56 +03:00
Willy Tarreau 12aebfac27 floppy: cleanup: add a few comments about expectations in certain functions
The locking in the driver is far from being obvious, with unlocking
automatically happening at end of operations scheduled by interrupt,
especially for the error paths where one does not necessarily expect
that such an interrupt may be triggered. Let's add a few comments
about what to expect at certain places to avoid misdetecting bugs
which are not.

Link: https://lore.kernel.org/r/20200331094054.24441-24-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:55 +03:00
Willy Tarreau 82a6301058 floppy: cleanup: do not iterate on current_fdc in DMA grab/release functions
Both floppy_grab_irq_and_dma() and floppy_release_irq_and_dma() used to
iterate on the global variable while setting up or freeing resources.
Now that they exclusively rely on functions which take the fdc as an
argument, so let's not touch the global one anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-23-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:55 +03:00
Willy Tarreau e5a9c95f9b floppy: cleanup: make get_fdc_version() not rely on current_fdc anymore
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-22-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:55 +03:00
Willy Tarreau 43d81bb647 floppy: cleanup: make next_valid_format() not rely on current_drive anymore
Now the drive is passed in argument so that the function does not
use current_drive anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-21-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:55 +03:00
Willy Tarreau c7af70b0fb floppy: cleanup: make check_wp() not rely on current_{fdc,drive} anymore
Now the fdc and drive are passed in argument so that the function does
not use current_fdc nor current_drive anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-20-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:55 +03:00
Willy Tarreau 3631a674a2 floppy: cleanup: make fdc_specify() not rely on current_{fdc,drive} anymore
Now the fdc and drive are passed in argument so that the function does
not use current_fdc nor current_drive anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-19-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:55 +03:00
Willy Tarreau d5da6fa2b8 floppy: cleanup: make fdc_configure() not rely on current_fdc anymore
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-18-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:55 +03:00
Willy Tarreau 197c7ffdb8 floppy: cleanup: make perpendicular_mode() not rely on current_fdc anymore
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.

It's worth noting that there's still a single raw_cmd pointer
specific to the current fdc. It may make sense to have one per
fdc in the future. In addition, cont->done() still relies on the
current drive and current raw_cmd.

Link: https://lore.kernel.org/r/20200331094054.24441-17-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:54 +03:00
Willy Tarreau 3ab12a1820 floppy: cleanup: make need_more_output() not rely on current_fdc anymore
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-16-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:54 +03:00
Willy Tarreau 96dad77a65 floppy: cleanup: make result() not rely on current_fdc anymore
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.

It's worth noting that there's still a single reply_buffer[] which
will store the result for the current fdc. It may or may not make
sense to implement one buffer per fdc in the future.

Link: https://lore.kernel.org/r/20200331094054.24441-15-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:54 +03:00
Willy Tarreau f8a8e0f7a8 floppy: cleanup: make output_byte() not rely on current_fdc anymore
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-14-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:54 +03:00
Willy Tarreau 5ea00bfc52 floppy: cleanup: make wait_til_ready() not rely on current_fdc anymore
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-13-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:54 +03:00
Willy Tarreau 6d494ed037 floppy: cleanup: make show_floppy() not rely on current_fdc anymore
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-12-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:54 +03:00
Willy Tarreau f3e0dc1d8b floppy: cleanup: make reset_fdc_info() not rely on current_fdc anymore
Now the fdc is passed in argument so that the function does not
use current_fdc anymore.

Link: https://lore.kernel.org/r/20200331094054.24441-11-w@1wt.eu
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Denis Efremov <efremov@linux.com>
2020-05-12 19:34:54 +03:00