NVMeOF controller in the passsthru mode is capable of handling wide set
of I/O commands including vender specific passhtru io comands.

The vendor specific I/O commands are used to read the large drive
logs and can take longer than default NVMe commands, i.e. for
passthru requests the timeout value may differ from the passthru
controller's default timeout values (nvme-core:io_timeout).

Add a configfs attribute so that user can set the io timeout values.
In case if this configfs value is not set nvme_alloc_request() will set
the NVME_IO_TIMEOUT value when request queuedata is NULL.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

NVMeOF controller in the passsthru mode is capable of handling wide set
of admin commands including vender specific passhtru admin comands.

The vendor specific admin commands are used to read the large drive
logs and can take longer than default NVMe commands, i.e. for
passthru requests the timeout value may differ from the passthru
controller's default timeout values (nvme-core:admin_timeout).

Add a configfs attribute so that user can set the admin timeout values.
In case if this configfs value is not set nvme_alloc_request() will set
the ADMIN_TIMEOUT value when request queuedata is NULL.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

This is purely a clenaup patch, add prefix NVME to the ADMIN_TIMEOUT to
make consistent with NVME_IO_TIMEOUT.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The function nvme_alloc_request() is called from different context
(I/O and Admin queue) where callers do not consider the I/O timeout when
called from I/O queue context.

Update nvme_alloc_request() to set the default I/O and Admin timeout
value based on whether the queuedata is set or not.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Use the request's '->mq_hctx->queue_num' directly to simplify the
nvme_req_qid() function.

Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Add sysfs attribute to specify parameters for dropping a command.  The
attribute takes a string of:

  <opcode>:<starting a what instance>:<number of times>

Opcode is formatted as lower 8 bits are opcode.  If a fabrics opcode, a
bit above bits 7:0 will be set.

Once set, each sqe is looked at. If the opcode matches the running
instance count is updated. If the instance count is in the range of where
to drop (based on starting and # of times), then drop the command by not
passing it to the target layer.

Signed-off-by: James Smart <james.smart@broadcom.com>

Merge branch 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-5.11/drivers

Pull MD changes from Song:

"Summary:
 1. Fix race condition in md_ioctl(), by Dae R. Jeong;
 2. Initialize read_slot properly for raid10, by Kevin Vigor;
 3. Code cleanup, by Pankaj Gupta;
 4. md-cluster resync/reshape fix, by Zhao Heming."

* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md/cluster: fix deadlock when node is doing resync job
  md/cluster: block reshape with remote resync job
  md: use current request time as base for ktime comparisons
  md: add comments in md_flush_request()
  md: improve variable names in md_flush_request()
  md/raid10: initialize r10_bio->read_slot before use.
  md: fix a warning caused by a race between concurrent md_ioctl()s

md-cluster uses MD_CLUSTER_SEND_LOCK to make node can exclusively send msg.
During sending msg, node can concurrently receive msg from another node.
When node does resync job, grab token_lockres:EX may trigger a deadlock:
```
nodeA                       nodeB
--------------------     --------------------
a.
send METADATA_UPDATED
held token_lockres:EX
                         b.
                         md_do_sync
                          resync_info_update
                            send RESYNCING
                             + set MD_CLUSTER_SEND_LOCK
                             + wait for holding token_lockres:EX

                         c.
                         mdadm /dev/md0 --remove /dev/sdg
                          + held reconfig_mutex
                          + send REMOVE
                             + wait_event(MD_CLUSTER_SEND_LOCK)

                         d.
                         recv_daemon //METADATA_UPDATED from A
                          process_metadata_update
                           + (mddev_trylock(mddev) ||
                              MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD)
                             //this time, both return false forever
```
Explaination:
a. A send METADATA_UPDATED
   This will block another node to send msg

b. B does sync jobs, which will send RESYNCING at intervals.
   This will be block for holding token_lockres:EX lock.

c. B do "mdadm --remove", which will send REMOVE.
   This will be blocked by step <b>: MD_CLUSTER_SEND_LOCK is 1.

d. B recv METADATA_UPDATED msg, which send from A in step <a>.
   This will be blocked by step <c>: holding mddev lock, it makes
   wait_event can't hold mddev lock. (btw,
   MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD keep ZERO in this scenario.)

There is a similar deadlock in commit 0ba95977


("md-cluster: use sync way to handle METADATA_UPDATED msg")
In that commit, step c is "update sb". This patch step c is
"mdadm --remove".

For fixing this issue, we can refer the solution of function:
metadata_update_start. Which does the same grab lock_token action.
lock_comm can use the same steps to avoid deadlock. By moving
MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD from lock_token to lock_comm.
It enlarge a little bit window of MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD,
but it is safe & can break deadlock.

Repro steps (I only triggered 3 times with hundreds tests):

two nodes share 3 iSCSI luns: sdg/sdh/sdi. Each lun size is 1GB.
```
ssh root@node2 "mdadm -S --scan"
mdadm -S --scan
for i in {g,h,i};do dd if=/dev/zero of=/dev/sd$i oflag=direct bs=1M \
count=20; done

mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sdg /dev/sdh \
 --bitmap-chunk=1M
ssh root@node2 "mdadm -A /dev/md0 /dev/sdg /dev/sdh"

sleep 5

mkfs.xfs /dev/md0
mdadm --manage --add /dev/md0 /dev/sdi
mdadm --wait /dev/md0
mdadm --grow --raid-devices=3 /dev/md0

mdadm /dev/md0 --fail /dev/sdg
mdadm /dev/md0 --remove /dev/sdg
mdadm --grow --raid-devices=2 /dev/md0
```

test script will hung when executing "mdadm --remove".

```
 # dump stacks by "echo t > /proc/sysrq-trigger"
md0_cluster_rec D    0  5329      2 0x80004000
Call Trace:
 __schedule+0x1f6/0x560
 ? _cond_resched+0x2d/0x40
 ? schedule+0x4a/0xb0
 ? process_metadata_update.isra.0+0xdb/0x140 [md_cluster]
 ? wait_woken+0x80/0x80
 ? process_recvd_msg+0x113/0x1d0 [md_cluster]
 ? recv_daemon+0x9e/0x120 [md_cluster]
 ? md_thread+0x94/0x160 [md_mod]
 ? wait_woken+0x80/0x80
 ? md_congested+0x30/0x30 [md_mod]
 ? kthread+0x115/0x140
 ? __kthread_bind_mask+0x60/0x60
 ? ret_from_fork+0x1f/0x40

mdadm           D    0  5423      1 0x00004004
Call Trace:
 __schedule+0x1f6/0x560
 ? __schedule+0x1fe/0x560
 ? schedule+0x4a/0xb0
 ? lock_comm.isra.0+0x7b/0xb0 [md_cluster]
 ? wait_woken+0x80/0x80
 ? remove_disk+0x4f/0x90 [md_cluster]
 ? hot_remove_disk+0xb1/0x1b0 [md_mod]
 ? md_ioctl+0x50c/0xba0 [md_mod]
 ? wait_woken+0x80/0x80
 ? blkdev_ioctl+0xa2/0x2a0
 ? block_ioctl+0x39/0x40
 ? ksys_ioctl+0x82/0xc0
 ? __x64_sys_ioctl+0x16/0x20
 ? do_syscall_64+0x5f/0x150
 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9

md0_resync      D    0  5425      2 0x80004000
Call Trace:
 __schedule+0x1f6/0x560
 ? schedule+0x4a/0xb0
 ? dlm_lock_sync+0xa1/0xd0 [md_cluster]
 ? wait_woken+0x80/0x80
 ? lock_token+0x2d/0x90 [md_cluster]
 ? resync_info_update+0x95/0x100 [md_cluster]
 ? raid1_sync_request+0x7d3/0xa40 [raid1]
 ? md_do_sync.cold+0x737/0xc8f [md_mod]
 ? md_thread+0x94/0x160 [md_mod]
 ? md_congested+0x30/0x30 [md_mod]
 ? kthread+0x115/0x140
 ? __kthread_bind_mask+0x60/0x60
 ? ret_from_fork+0x1f/0x40
```

At last, thanks for Xiao's solution.

Cc: stable@vger.kernel.org
Signed-off-by: Zhao Heming <heming.zhao@suse.com>
Suggested-by: Xiao Ni <xni@redhat.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

Reshape request should be blocked with ongoing resync job. In cluster
env, a node can start resync job even if the resync cmd isn't executed
on it, e.g., user executes "mdadm --grow" on node A, sometimes node B
will start resync job. However, current update_raid_disks() only check
local recovery status, which is incomplete. As a result, we see user will
execute "mdadm --grow" successfully on local, while the remote node deny
to do reshape job when it doing resync job. The inconsistent handling
cause array enter unexpected status. If user doesn't observe this issue
and continue executing mdadm cmd, the array doesn't work at last.

Fix this issue by blocking reshape request. When node executes "--grow"
and detects ongoing resync, it should stop and report error to user.

The following script reproduces the issue with ~100% probability.
(two nodes share 3 iSCSI luns: sdg/sdh/sdi. Each lun size is 1GB)
```
 # on node1, node2 is the remote node.
ssh root@node2 "mdadm -S --scan"
mdadm -S --scan
for i in {g,h,i};do dd if=/dev/zero of=/dev/sd$i oflag=direct bs=1M \
count=20; done

mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sdg /dev/sdh
ssh root@node2 "mdadm -A /dev/md0 /dev/sdg /dev/sdh"

sleep 5

mdadm --manage --add /dev/md0 /dev/sdi
mdadm --wait /dev/md0
mdadm --grow --raid-devices=3 /dev/md0

mdadm /dev/md0 --fail /dev/sdg
mdadm /dev/md0 --remove /dev/sdg
mdadm --grow --raid-devices=2 /dev/md0
```

Cc: stable@vger.kernel.org
Signed-off-by: Zhao Heming <heming.zhao@suse.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

Request coalescing logic uses 'prev_flush_start' as base to
compare the current request start time. 'prev_flush_start' is
updated in other context.

This patch changes this by using ktime comparison base to
'req_start' for better readability of code.

Signed-off-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

Request coalescing logic is dependent on flush time update in other
context. This patch adds comments to understand the code flow better.

Signed-off-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

This patch improves readability by using better variable names
in flush request coalescing logic.

Signed-off-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Song Liu <songliubraving@fb.com>

In __make_request() a new r10bio is allocated and passed to
raid10_read_request(). The read_slot member of the bio is not
initialized, and the raid10_read_request() uses it to index an
array. This leads to occasional panics.

Fix by initializing the field to invalid value and checking for
valid value in raid10_read_request().

Cc: stable@vger.kernel.org
Signed-off-by: Kevin Vigor <kvigor@gmail.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

Syzkaller reports a warning as belows.
WARNING: CPU: 0 PID: 9647 at drivers/md/md.c:7169
...
Call Trace:
...
RIP: 0010:md_ioctl+0x4017/0x5980 drivers/md/md.c:7169
RSP: 0018:ffff888096027950 EFLAGS: 00010293
RAX: ffff88809322c380 RBX: 0000000000000932 RCX: ffffffff84e266f2
RDX: 0000000000000000 RSI: ffffffff84e299f7 RDI: 0000000000000007
RBP: ffff888096027bc0 R08: ffff88809322c380 R09: ffffed101341a482
R10: ffff888096027940 R11: ffff88809a0d240f R12: 0000000000000932
R13: ffff8880a2c14100 R14: ffff88809a0d2268 R15: ffff88809a0d2408
 __blkdev_driver_ioctl block/ioctl.c:304 [inline]
 blkdev_ioctl+0xece/0x1c10 block/ioctl.c:606
 block_ioctl+0xee/0x130 fs/block_dev.c:1930
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

This is caused by a race between two concurrenct md_ioctl()s closing
the array.
CPU1 (md_ioctl())                   CPU2 (md_ioctl())
------                              ------
set_bit(MD_CLOSING, &mddev->flags);
did_set_md_closing = true;
                                    WARN_ON_ONCE(test_bit(MD_CLOSING,
                                            &mddev->flags));
if(did_set_md_closing)
    clear_bit(MD_CLOSING, &mddev->flags);

Fix the warning by returning immediately if the MD_CLOSING bit is set
in &mddev->flags which indicates that the array is being closed.

Fixes: 065e519e

 ("md: MD_CLOSING needs to be cleared after called md_set_readonly or do_md_stop")
Reported-by:  <syzbot+1e46a0864c1a6e9bd3d8@syzkaller.appspotmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dae R. Jeong <dae.r.jeong@kaist.ac.kr>
Signed-off-by: Song Liu <songliubraving@fb.com>

If the Fibre Channel Endpoint-Security status of a path changes, a
corresponding path event is received from the CIO layer.

Process this event by re-reading the FCES information.

As the information is retrieved for all paths on a single CU in one
call, the internal status can also be updated for all paths and no
processing per path is necessary.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

As more path events need to be handled for ECKD the current path
verification infrastructure can be reused. Rename all path verifcation
code to fit the more broadly based task of path event handling and put
the path verification in a new separate function.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add a new sysfs attribute (fc_security) per device and per operational
channel path. The information of the current FC Endpoint Security state
is received through the CIO layer.

The state of the FC Endpoint Security can be either "Unsupported",
"Authentication", or "Encryption".

For example:
$ cat /sys/bus/ccw/devices/0.0.c600/fc_security
Encryption

If any of the operational paths is in a state different from all
others, the device sysfs attribute will display the additional state
"Inconsistent".

The sysfs attributes per paths are organised in a new directory called
"paths_info" with subdirectories for each path.

/sys/bus/ccw/devices/0.0.c600/paths_info/
├── 0.38
│   └── fc_security
├── 0.39
│   └── fc_security
├── 0.3a
│   └── fc_security
└── 0.3b
    └── fc_security

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

During online processing and setting up a DASD device, the configuration
data for operational paths is read and validated two times
(dasd_eckd_read_conf()). The first time to provide information that are
necessary for the LCU setup. A second time after the LCU setup as a
device might report different configuration data then.

When the configuration setup for each operational path is being
validated, an initial call to dasd_eckd_clear_conf_data() is issued.
This call wipes all previously available configuration data and path
information for each path.
However, the operational path mask is not updated during this process.

As a result, the stored operational path mask might no longer correspond
to the operational paths mask reported by the CIO layer, as several
paths might be gone between the two dasd_eckd_read_conf() calls.

This inconsistency leads to more severe issues in later path handling
changes. Fix this by removing the channel paths from the operational
path mask during the dasd_eckd_clear_conf_data() call.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Currently, the configuration data for a path is retrieved during a path
verification and used only temporarily. If a path is newly added to the
I/O setup after a boot, no configuration data will be stored for this
particular path.
However, this data is required for later use and should be present for
a valid I/O path anyway. Store this data during the path verification so
that newly added paths can provide all information necessary.

[sth@linux.ibm.com: fix conf_data memleak]

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

For storing retrieved path information both the if and else block in
dasd_eckd_read_conf() use the same code. To avoid duplicate code this
should be done after the if/else block. To further increase readability,
move the code to a new function, dasd_eckd_store_conf_data().

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The discipline argument in dasd_generic_probe() isn't used and there is
no history how it was used in the past. Remove it.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Fibre Channel Endpoint-Security event is received as an sei:nt0 type
in the CIO layer. This information needs to be shared with the
CCW device drivers using the path_events callback.

Co-developed-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add an interface in the CIO layer to retrieve the information about the
Endpoint-Security Mode (ESM) of the specified CU. The ESM values are
defined as 0-None, 1-Authenticated or 2, 3-Encrypted.

[vneethv@linux.ibm.com: cleaned-up and modified description]

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add a new sysfs attribute 'esc' per chpid. This new attribute exports
the Endpoint-Security-Capability byte of channel-path description block,
which could be 0-None, 1-Authentication, 2 and 3-Encryption.

For example:
$ cat /sys/devices/css0/chp0.34/esc
0

[vneethv@linux.ibm.com: cleaned-up & modified description]

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Switch the comment to talk about __register_blkdev instead of
register_blkdev and document the new probe parameter.

Fixes: 3da1a61e7046 ("block: add an optional probe callback to major_names")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Now that bdev_map is only used for finding gendisks, we can use
a simple xarray instead of the regions tracking structure for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Use separate gendisks (which share a tag_set) for the different operating
modes instead of redirecting the gendisk lookup using a probe callback.
This avoids potential problems with aliased block_device instances and
will eventually allow for removing the blk_register_region framework.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

reindent the driver using Lident as the code style was far away from
normal Linux code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The Atari floppy driver usually autodetects the media when used with the
ormal /dev/fd? devices, which also are the only nodes created by udev.
But it also supports various aliases that force a given media format.
That is currently supported using the blk_register_region framework
which finds the floppy gendisk even for a 'mismatched' dev_t.  The
problem with this (besides the code complexity) is that it creates
multiple struct block_device instances for the whole device of a
single gendisk, which can lead to interesting issues in code not
aware of that fact.

To fix this just create a separate gendisk for each of the aliases
if they are accessed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Use separate gendisks (which share a tag_set) for the native Amgiga vs
the MS-DOS mode instead of redirecting the gendisk lookup using a probe
callback.  This avoids potential problems with aliased block_device
instances and will eventually allow for removing the blk_register_region
framework.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The floppy driver usually autodetects the media when used with the
normal /dev/fd? devices, which also are the only nodes created by udev.
But it also supports various aliases that force a given media format.
That is currently supported using the blk_register_region framework
which finds the floppy gendisk even for a 'mismatched' dev_t.  The
problem with this (besides the code complexity) is that it creates
multiple struct block_device instances for the whole device of a
single gendisk, which can lead to interesting issues in code not
aware of that fact.

To fix this just create a separate gendisk for each of the aliases
if they are accessed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

ide is the last user of the blk_register_region framework except for the
tracking of allocated gendisk.  Switch to __register_blkdev, even if that
doesn't allow us to trivially find out which command set to probe for.
That means we now always request all modules when a user tries to access
an unclaimed ide device node, but except for a few potentially loaded
modules for a fringe use case of a deprecated and soon to be removed
driver that doesn't make a difference.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Use the simpler mechanism attached to major_name to allocate a md device
when a currently unregistered minor is accessed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Use the simpler mechanism attached to major_name to allocate a brd device
when a currently unregistered minor is accessed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Use the simpler mechanism attached to major_name to allocate a brd device
when a currently unregistered minor is accessed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Switch from using blk_register_region to the probe callback passed to
__register_blkdev to disable the request_module call for an unclaimed
dev_t in the SD majors.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The swim driver (unlike various other floppy drivers) doesn't have
magic device nodes for certain modes, and already registers a gendisk
for each of the floppies supported by a device.  Thus the region
registered is a no-op and can be removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

There is no need to ever register the fake gendisk used for ide-tape.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add a callback to the major_names array that allows a driver to override
how to probe for dev_t that doesn't currently have a gendisk registered.
This will help separating the lookup of the gendisk by dev_t vs probe
action for a not currently registered dev_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Instead of reusing the ranges in bdev_map, add a new helper that is
called if no ranges was found.  This is a first step to unpeel and
eventually remove the complex ranges structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>