GFP_NOWAIT allocation may fail anytime. It needs to be changed to
GFP_NOIO. There's no need to handle an error because mempool_alloc with
GFP_NOIO can't fail.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Eric Biggers <ebiggers@kernel.org>

An empty flush bio can have arbitrary bi_sector. The commit 2b1c6d7a890a
introduced a regression that device mapper would fail an empty flush bio
with -EIO if the sector pointed beyond the end of the device.

The commit introduced an optimization, that optimization would pass
flushes to __split_and_process_bio and __split_and_process_bio is not
prepared to handle empty bios. Fix this bug by passing only non-empty
flushes to __split_and_process_bio - non-empty flushes must have valid
bi_sector. Empty bios will go through __send_empty_flush, as they did
before the optimization.

This problem can be reproduced by running the lvm2 test:
make check_local T=lvconvert-thin.sh LVM_TEST_PREFER_BRD=0

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 2b1c6d7a890a ("dm: optimize REQ_PREFLUSH with data when using the linear target")
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>

pcache_meta_find_latest() leaves whatever it last copied into the
caller’s buffer even when it returns NULL. For cache_info_init(),
that meant cache->cache_info could still contain CRC-bad garbage when
no valid metadata exists, leading later initialization paths to read
bogus flags.

Explicitly memset cache->cache_info in cache_info_init_default()
so new-cache paths start from a clean slate. The default sequence
number assignment becomes redundant with this reset, so it drops out.

Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Reviewed-by: Zheng Gu <cengku@gmail.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

pcache_meta_find_latest() already computes the metadata address as
meta_addr. Reuse that instead of recomputing.

Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

CONFIG_BCACHE is tristate, so dm-pcache can also be built-in.
Switch the Makefile to use obj-$(CONFIG_DM_PCACHE) so the target can be
linked into vmlinux instead of always being a loadable module.

Also rename cache_flush() to pcache_cache_flush() to avoid a global
symbol clash with sunrpc/cache.c's cache_flush().

Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

Pull device mapper updates from Mikulas Patocka:

 - a new dm-pcache target for read/write caching on persistent memory

 - fix typos in docs

 - misc small refactoring

 - mark dm-error with DM_TARGET_PASSES_INTEGRITY

 - dm-request-based: fix NULL pointer dereference and quiesce_depth out of sync

 - dm-linear: optimize REQ_PREFLUSH

 - dm-vdo: return error on corrupted metadata

 - dm-integrity: support asynchronous hash interface

* tag 'for-6.18/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (27 commits)
  dm raid: use proper md_ro_state enumerators
  dm-integrity: prefer synchronous hash interface
  dm-integrity: enable asynchronous hash interface
  dm-integrity: rename internal_hash
  dm-integrity: add the "offset" argument
  dm-integrity: allocate the recalculate buffer with kmalloc
  dm-integrity: introduce integrity_kmap and integrity_kunmap
  dm-integrity: replace bvec_kmap_local with kmap_local_page
  dm-integrity: use internal variable for digestsize
  dm vdo: return error on corrupted metadata in start_restoring_volume functions
  dm vdo: Update code to use mem_is_zero
  dm: optimize REQ_PREFLUSH with data when using the linear target
  dm-pcache: use int type to store negative error codes
  dm: fix "writen"->"written"
  dm-pcache: cleanup: fix coding style report by checkpatch.pl
  dm-pcache: remove ctrl_lock for pcache_cache_segment
  dm: fix NULL pointer dereference in __dm_suspend()
  dm: fix queue start/stop imbalance under suspend/load/resume races
  dm-pcache: add persistent cache target in device-mapper
  dm error: mark as DM_TARGET_PASSES_INTEGRITY
  ...

Pull block updates from Jens Axboe:

 - NVMe pull request via Keith:
     - FC target fixes (Daniel)
     - Authentication fixes and updates (Martin, Chris)
     - Admin controller handling (Kamaljit)
     - Target lockdep assertions (Max)
     - Keep-alive updates for discovery (Alastair)
     - Suspend quirk (Georg)

 - MD pull request via Yu:
     - Add support for a lockless bitmap.

       A key feature for the new bitmap are that the IO fastpath is
       lockless. If a user issues lots of write IO to the same bitmap
       bit in a short time, only the first write has additional overhead
       to update bitmap bit, no additional overhead for the following
       writes.

       By supporting only resync or recover written data, means in the
       case creating new array or replacing with a new disk, there is no
       need to do a full disk resync/recovery.

 - Switch ->getgeo() and ->bios_param() to using struct gendisk rather
   than struct block_device.

 - Rust block changes via Andreas. This series adds configuration via
   configfs and remote completion to the rnull driver. The series also
   includes a set of changes to the rust block device driver API: a few
   cleanup patches, and a few features supporting the rnull changes.

   The series removes the raw buffer formatting logic from
   `kernel::block` and improves the logic available in `kernel::string`
   to support the same use as the removed logic.

 - floppy arch cleanups

 - Reduce the number of dereferencing needed for ublk commands

 - Restrict supported sockets for nbd. Mostly done to eliminate a class
   of issues perpetually reported by syzbot, by using nonsensical socket
   setups.

 - A few s390 dasd block fixes

 - Fix a few issues around atomic writes

 - Improve DMA interation for integrity requests

 - Improve how iovecs are treated with regards to O_DIRECT aligment
   constraints.

   We used to require each segment to adhere to the constraints, now
   only the request as a whole needs to.

 - Clean up and improve p2p support, enabling use of p2p for metadata
   payloads

 - Improve locking of request lookup, using SRCU where appropriate

 - Use page references properly for brd, avoiding very long RCU sections

 - Fix ordering of recursively submitted IOs

 - Clean up and improve updating nr_requests for a live device

 - Various fixes and cleanups

* tag 'for-6.18/block-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (164 commits)
  s390/dasd: enforce dma_alignment to ensure proper buffer validation
  s390/dasd: Return BLK_STS_INVAL for EINVAL from do_dasd_request
  ublk: remove redundant zone op check in ublk_setup_iod()
  nvme: Use non zero KATO for persistent discovery connections
  nvmet: add safety check for subsys lock
  nvme-core: use nvme_is_io_ctrl() for I/O controller check
  nvme-core: do ioccsz/iorcsz validation only for I/O controllers
  nvme-core: add method to check for an I/O controller
  blk-cgroup: fix possible deadlock while configuring policy
  blk-mq: fix null-ptr-deref in blk_mq_free_tags() from error path
  blk-mq: Fix more tag iteration function documentation
  selftests: ublk: fix behavior when fio is not installed
  ublk: don't access ublk_queue in ublk_unmap_io()
  ublk: pass ublk_io to __ublk_complete_rq()
  ublk: don't access ublk_queue in ublk_need_complete_req()
  ublk: don't access ublk_queue in ublk_check_commit_and_fetch()
  ublk: don't pass ublk_queue to ublk_fetch()
  ublk: don't access ublk_queue in ublk_config_io_buf()
  ublk: don't access ublk_queue in ublk_check_fetch_buf()
  ublk: pass q_id and tag to __ublk_check_and_get_req()
  ...

Pull dlm updates from David Teigland:
 "This adds a dlm_release_lockspace() flag to request that node-failure
  recovery be performed for the node leaving the lockspace.

  The implementation of this flag requires coordination with userland
  clustering components. It's been requested for use by GFS2"

* tag 'dlm-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
  dlm: check for undefined release_option values
  dlm: handle release_option as unsigned
  dlm: move to rinfo for all middle conversion cases
  dlm: handle invalid lockspace member remove
  dlm: add new flag DLM_RELEASE_RECOVER for dlm_lockspace_release
  dlm: add new configfs entry release_recover for lockspace members
  dlm: add new RELEASE_RECOVER uevent attribute for release_lockspace
  dlm: use defines for force values in dlm_release_lockspace
  dlm: check for defined force value in dlm_lockspace_release

The dm-raid code was using hardcoded integer values to represent the
read-only/read-write state of RAID arrays instead of the proper
enumeration constants defined in the md_ro_state enumerator type.

Changes:

- Replace hardcoded integers with the appropriate md_ro_state enumerator
  values

- Add the missing MD_RDONLY setting in the post_suspend function
  (no failures have been attributed to this inconsistency, the fix
  ensures correct state transitions for completeness)

This improves code clarity and maintainability by using the defined
enumeration constants rather than magic numbers, ensuring the code
properly conforms to the established API interface.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

The previous patch preferred async interface for the purpose of testing.
However, the synchronous interface is faster, so it should be preferred.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>