Merge tag 'for-6.19/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mikulas Patocka:

 - convert crypto_shash users to direct crypto library use with simpler
   and faster code and reduced stack usage (Eric Biggers):

     - the dm-verity SHA-256 conversion also teaches it to do two-way
       interleaved hashing for added performance

     - dm-crypt MD5 conversion (used for Loop-AES compatibility)

 - added document for for takeover/reshape raid1 -> raid5 examples (Heinz Mauelshagen)

 - fix dm-vdo kerneldoc warnings (Matthew Sakai)

 - various random fixes and cleanups

* tag 'for-6.19/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (29 commits)
  dm pcache: fix segment info indexing
  dm pcache: fix cache info indexing
  dm-pcache: advance slot index before writing slot
  dm raid: add documentation for takeover/reshape raid1 -> raid5 table line examples
  dm log-writes: Add missing set_freezable() for freezable kthread
  dm-raid: fix possible NULL dereference with undefined raid type
  dm-snapshot: fix 'scheduling while atomic' on real-time kernels
  dm: ignore discard return value
  MAINTAINERS: add Benjamin Marzinski as a device mapper maintainer
  dm-mpath: Simplify the setup_scsi_dh code
  dm vdo: fix kerneldoc warnings
  dm-bufio: align write boundary on physical block size
  dm-crypt: enable DM_TARGET_ATOMIC_WRITES
  dm: test for REQ_ATOMIC in dm_accept_partial_bio()
  dm-verity: remove useless mempool
  dm-verity: disable recursive forward error correction
  dm-ebs: Mark full buffer dirty even on partial write
  dm mpath: enable DM_TARGET_ATOMIC_WRITES
  dm verity fec: Expose corrected block count via status
  dm: Don't warn if IMA_DISABLE_HTABLE is not enabled
  ...

2 files changed, 77 insertions, 9 deletions

diff --git a/Documentation/admin-guide/device-mapper/dm-raid.rst b/Documentation/admin-guide/device-mapper/dm-raid.rst
index bb17e26e3c1b..e11f10764770 100644
--- a/Documentation/admin-guide/device-mapper/dm-raid.rst
+++ b/Documentation/admin-guide/device-mapper/dm-raid.rst
@@ -20,10 +20,10 @@ The target is named "raid" and it accepts the following parameters::
   raid0		RAID0 striping (no resilience)
   raid1		RAID1 mirroring
   raid4		RAID4 with dedicated last parity disk
-  raid5_n 	RAID5 with dedicated last parity disk supporting takeover
+  raid5_n 	RAID5 with dedicated last parity disk supporting takeover from/to raid1
 		Same as raid4
 
-		- Transitory layout
+		- Transitory layout for takeover from/to raid1
   raid5_la	RAID5 left asymmetric
 
 		- rotating parity 0 with data continuation
@@ -48,8 +48,8 @@ The target is named "raid" and it accepts the following parameters::
   raid6_n_6	RAID6 with dedicate parity disks
 
 		- parity and Q-syndrome on the last 2 disks;
-		  layout for takeover from/to raid4/raid5_n
-  raid6_la_6	Same as "raid_la" plus dedicated last Q-syndrome disk
+		  layout for takeover from/to raid0/raid4/raid5_n
+  raid6_la_6	Same as "raid_la" plus dedicated last Q-syndrome disk supporting takeover from/to raid5
 
 		- layout for takeover from raid5_la from/to raid6
   raid6_ra_6	Same as "raid5_ra" dedicated last Q-syndrome disk
@@ -173,9 +173,9 @@ The target is named "raid" and it accepts the following parameters::
 		The delta_disks option value (-251 < N < +251) triggers
 		device removal (negative value) or device addition (positive
 		value) to any reshape supporting raid levels 4/5/6 and 10.
-		RAID levels 4/5/6 allow for addition of devices (metadata
-		and data device tuple), raid10_near and raid10_offset only
-		allow for device addition. raid10_far does not support any
+		RAID levels 4/5/6 allow for addition and removal of devices
+                (metadata and data device tuple), raid10_near and raid10_offset
+                only allow for device addition. raid10_far does not support any
 		reshaping at all.
 		A minimum of devices have to be kept to enforce resilience,
 		which is 3 devices for raid4/5 and 4 devices for raid6.
@@ -372,6 +372,72 @@ to safely enable discard support for RAID 4/5/6:
     'devices_handle_discards_safely'
 
 
+Takeover/Reshape Support
+------------------------
+The target natively supports these two types of MDRAID conversions:
+
+o Takeover: Converts an array from one RAID level to another
+
+o Reshape: Changes the internal layout while maintaining the current RAID level
+
+Each operation is only valid under specific constraints imposed by the existing array's layout and configuration.
+
+
+Takeover:
+linear -> raid1 with N >= 2 mirrors
+raid0 -> raid4 (add dedicated parity device)
+raid0 -> raid5 (add dedicated parity device)
+raid0 -> raid10 with near layout and N >= 2 mirror groups (raid0 stripes have to become first member within mirror groups)
+raid1 -> linear
+raid1 -> raid5 with 2 mirrors
+raid4 -> raid5 w/ rotating parity
+raid5 with dedicated parity device -> raid4
+raid5 -> raid6 (with dedicated Q-syndrome)
+raid6 (with dedicated Q-syndrome) -> raid5
+raid10 with near layout and even number of disks -> raid0 (select any in-sync device from each mirror group)
+
+Reshape:
+linear: not possible
+raid0:  not possible
+raid1:  change number of mirrors
+raid4:  add and remove stripes (minimum 3), change stripesize
+raid5:  add and remove stripes (minimum 3, special case 2 for raid1 takeover), change rotating parity algorithms, change stripesize
+raid6:  add and remove stripes (minimum 4), change rotating syndrome algorithms, change stripesize
+raid10 near:   add stripes (minimum 4), change stripesize, no stripe removal possible, change to offset layout
+raid10 offset: add stripes, change stripesize, no stripe removal possible, change to near layout
+raid10 far:    not possible
+
+Table line examples:
+
+### raid1 -> raid5
+#
+# 2 devices limitation in raid1.
+# raid5 personality is able to just map 2 like raid1.
+# Reshape after takeover to change to full raid5 layout
+
+  0 1960886272 raid raid1 3 0 region_size 2048 2 /dev/dm-0 /dev/dm-1 /dev/dm-2 /dev/dm-3
+
+# dm-0 and dm-2 are e.g. 4MiB large metadata devices, dm-1 and dm-3 have to be at least 1960886272 big.
+#
+# Table line to takeover to raid5
+
+  0 1960886272 raid raid5 3 0 region_size 2048 2 /dev/dm-0 /dev/dm-1 /dev/dm-2 /dev/dm-3
+
+# Add required out-of-place reshape space to the beginniong of the given 2 data devices,
+# allocate another metadata/data device tuple with the same sizes for the parity space
+# and zero the first 4K of the metadata device.
+#
+# Example table of the out-of-place reshape space addition for one data device, e.g. dm-1
+
+  0 8192 linear 8:0 0 1960903888 #  <- must be free space segment
+  8192 1960886272 linear 8:0 0 2048 # previous data segment
+
+# Mapping table for e.g. raid5_rs reshape causing the size of the raid device to double-fold once the reshape finishes.
+# Check the status output (e.g. "dmsetup status $RaidDev") for progess.
+
+  0 $((2 * 1960886272)) raid raid5 7 0 region_size 2048 data_offset 8192 delta_disk 1 2 /dev/dm-0 /dev/dm-1 /dev/dm-2 /dev/dm-3
+
+
 Version History
 ---------------
 
diff --git a/Documentation/admin-guide/device-mapper/verity.rst b/Documentation/admin-guide/device-mapper/verity.rst
index 8c3f1f967a3c..3ecab1cff9c6 100644
--- a/Documentation/admin-guide/device-mapper/verity.rst
+++ b/Documentation/admin-guide/device-mapper/verity.rst
@@ -236,8 +236,10 @@ is available at the cryptsetup project's wiki page
 
 Status
 ======
-V (for Valid) is returned if every check performed so far was valid.
-If any check failed, C (for Corruption) is returned.
+1. V (for Valid) is returned if every check performed so far was valid.
+   If any check failed, C (for Corruption) is returned.
+2. Number of corrected blocks by Forward Error Correction.
+   '-' if Forward Error Correction is not enabled.
 
 Example
 =======