Merge tag 'for-5.15/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Add DM infrastructure for IMA-based remote attestion. These changes
   are the basis for deploying DM-based storage in a "cloud" that must
   validate configurations end-users run to maintain trust. These DM
   changes allow supported DM targets' configurations to be measured via
   IMA. But the policy and enforcement (of which configurations are
   valid) is managed by something outside the kernel (e.g. Keylime).

 - Fix DM crypt scalability regression on systems with many cpus due to
   percpu_counter spinlock contention in crypt_page_alloc().

 - Use in_hardirq() instead of deprecated in_irq() in DM crypt.

 - Add event counters to DM writecache to allow users to further assess
   how the writecache is performing.

 - Various code cleanup in DM writecache's main IO mapping function.

* tag 'for-5.15/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm crypt: use in_hardirq() instead of deprecated in_irq()
  dm ima: update dm documentation for ima measurement support
  dm ima: update dm target attributes for ima measurements
  dm ima: add a warning in dm_init if duplicate ima events are not measured
  dm ima: prefix ima event name related to device mapper with dm_
  dm ima: add version info to dm related events in ima log
  dm ima: prefix dm table hashes in ima log with hash algorithm
  dm crypt: Avoid percpu_counter spinlock contention in crypt_page_alloc()
  dm: add documentation for IMA measurement support
  dm: update target status functions to support IMA measurement
  dm ima: measure data on device rename
  dm ima: measure data on table clear
  dm ima: measure data on device remove
  dm ima: measure data on device resume
  dm ima: measure data on table load
  dm writecache: add event counters
  dm writecache: report invalid return from writecache_map helpers
  dm writecache: further writecache_map() cleanup
  dm writecache: factor out writecache_map_remap_origin()
  dm writecache: split up writecache_map() to improve code readability

3 files changed, 730 insertions, 2 deletions

diff --git a/Documentation/admin-guide/device-mapper/dm-ima.rst b/Documentation/admin-guide/device-mapper/dm-ima.rst
new file mode 100644
index 000000000000..a4aa50a828e0
--- /dev/null
+++ b/Documentation/admin-guide/device-mapper/dm-ima.rst
@@ -0,0 +1,715 @@
+======
+dm-ima
+======
+
+For a given system, various external services/infrastructure tools
+(including the attestation service) interact with it - both during the
+setup and during rest of the system run-time.  They share sensitive data
+and/or execute critical workload on that system.  The external services
+may want to verify the current run-time state of the relevant kernel
+subsystems before fully trusting the system with business-critical
+data/workload.
+
+Device mapper plays a critical role on a given system by providing
+various important functionalities to the block devices using various
+target types like crypt, verity, integrity etc.  Each of these target
+types’ functionalities can be configured with various attributes.
+The attributes chosen to configure these target types can significantly
+impact the security profile of the block device, and in-turn, of the
+system itself.  For instance, the type of encryption algorithm and the
+key size determines the strength of encryption for a given block device.
+
+Therefore, verifying the current state of various block devices as well
+as their various target attributes is crucial for external services before
+fully trusting the system with business-critical data/workload.
+
+IMA kernel subsystem provides the necessary functionality for
+device mapper to measure the state and configuration of
+various block devices -
+
+- by device mapper itself, from within the kernel,
+- in a tamper resistant way,
+- and re-measured - triggered on state/configuration change.
+
+Setting the IMA Policy:
+=======================
+For IMA to measure the data on a given system, the IMA policy on the
+system needs to be updated to have following line, and the system needs
+to be restarted for the measurements to take effect.
+
+::
+
+ /etc/ima/ima-policy
+    measure func=CRITICAL_DATA label=device-mapper template=ima-buf
+
+The measurements will be reflected in the IMA logs, which are located at:
+
+::
+
+ /sys/kernel/security/integrity/ima/ascii_runtime_measurements
+ /sys/kernel/security/integrity/ima/binary_runtime_measurements
+
+Then IMA ASCII measurement log has the following format:
+
+::
+
+ <PCR> <TEMPLATE_DATA_DIGEST> <TEMPLATE_NAME> <TEMPLATE_DATA>
+
+ PCR := Platform Configuration Register, in which the values are registered.
+       This is applicable if TPM chip is in use.
+
+ TEMPLATE_DATA_DIGEST := Template data digest of the IMA record.
+ TEMPLATE_NAME := Template name that registered the integrity value (e.g. ima-buf).
+
+ TEMPLATE_DATA := <ALG> ":" <EVENT_DIGEST> <EVENT_NAME> <EVENT_DATA>
+                  It contains data for the specific event to be measured,
+                  in a given template data format.
+
+ ALG := Algorithm to compute event digest
+ EVENT_DIGEST := Digest of the event data
+ EVENT_NAME := Description of the event (e.g. 'dm_table_load').
+ EVENT_DATA := The event data to be measured.
+
+|
+
+| *NOTE #1:*
+| The DM target data measured by IMA subsystem can alternatively
+ be queried from userspace by setting DM_IMA_MEASUREMENT_FLAG with
+ DM_TABLE_STATUS_CMD.
+
+|
+
+| *NOTE #2:*
+| The Kernel configuration CONFIG_IMA_DISABLE_HTABLE allows measurement of duplicate records.
+| To support recording duplicate IMA events in the IMA log, the Kernel needs to be configured with
+ CONFIG_IMA_DISABLE_HTABLE=y.
+
+Supported Device States:
+========================
+Following device state changes will trigger IMA measurements:
+
+ 1. Table load
+ #. Device resume
+ #. Device remove
+ #. Table clear
+ #. Device rename
+
+1. Table load:
+---------------
+When a new table is loaded in a device's inactive table slot,
+the device information and target specific details from the
+targets in the table are measured.
+
+The IMA measurement log has the following format for 'dm_table_load':
+
+::
+
+ EVENT_NAME := "dm_table_load"
+ EVENT_DATA := <dm_version_str> ";" <device_metadata> ";" <table_load_data>
+
+ dm_version_str := "dm_version=" <N> "." <N> "." <N>
+                  Same as Device Mapper driver version.
+ device_metadata := <device_name> "," <device_uuid> "," <device_major> "," <device_minor> ","
+                   <minor_count> "," <num_device_targets> ";"
+
+ device_name := "name=" <dm-device-name>
+ device_uuid := "uuid=" <dm-device-uuid>
+ device_major := "major=" <N>
+ device_minor := "minor=" <N>
+ minor_count := "minor_count=" <N>
+ num_device_targets := "num_targets=" <N>
+ dm-device-name := Name of the device. If it contains special characters like '\', ',', ';',
+                   they are prefixed with '\'.
+ dm-device-uuid := UUID of the device. If it contains special characters like '\', ',', ';',
+                   they are prefixed with '\'.
+
+ table_load_data := <target_data>
+                    Represents the data (as name=value pairs) from various targets in the table,
+                    which is being loaded into the DM device's inactive table slot.
+ target_data := <target_data_row> | <target_data><target_data_row>
+
+ target_data_row := <target_index> "," <target_begin> "," <target_len> "," <target_name> ","
+                    <target_version> "," <target_attributes> ";"
+ target_index := "target_index=" <N>
+                 Represents nth target in the table (from 0 to N-1 targets specified in <num_device_targets>)
+                 If all the data for N targets doesn't fit in the given buffer - then the data that fits
+                 in the buffer (say from target 0 to x) is measured in a given IMA event.
+                 The remaining data from targets x+1 to N-1 is measured in the subsequent IMA events,
+                 with the same format as that of 'dm_table_load'
+                 i.e. <dm_version_str> ";" <device_metadata> ";" <table_load_data>.
+
+ target_begin := "target_begin=" <N>
+ target_len := "target_len=" <N>
+ target_name := Name of the target. 'linear', 'crypt', 'integrity' etc.
+                The targets that are supported for IMA measurements are documented below in the
+                'Supported targets' section.
+ target_version := "target_version=" <N> "." <N> "." <N>
+ target_attributes := Data containing comma separated list of name=value pairs of target specific attributes.
+
+ For instance, if a linear device is created with the following table entries,
+  # dmsetup create linear1
+  0 2 linear /dev/loop0 512
+  2 2 linear /dev/loop0 512
+  4 2 linear /dev/loop0 512
+  6 2 linear /dev/loop0 512
+
+ Then IMA ASCII measurement log will have the following entry:
+ (converted from ASCII to text for readability)
+
+ 10 a8c5ff755561c7a28146389d1514c318592af49a ima-buf sha256:4d73481ecce5eadba8ab084640d85bb9ca899af4d0a122989252a76efadc5b72
+ dm_table_load
+ dm_version=4.45.0;
+ name=linear1,uuid=,major=253,minor=0,minor_count=1,num_targets=4;
+ target_index=0,target_begin=0,target_len=2,target_name=linear,target_version=1.4.0,device_name=7:0,start=512;
+ target_index=1,target_begin=2,target_len=2,target_name=linear,target_version=1.4.0,device_name=7:0,start=512;
+ target_index=2,target_begin=4,target_len=2,target_name=linear,target_version=1.4.0,device_name=7:0,start=512;
+ target_index=3,target_begin=6,target_len=2,target_name=linear,target_version=1.4.0,device_name=7:0,start=512;
+
+2. Device resume:
+------------------
+When a suspended device is resumed, the device information and the hash of the
+data from previous load of an active table are measured.
+
+The IMA measurement log has the following format for 'dm_device_resume':
+
+::
+
+ EVENT_NAME := "dm_device_resume"
+ EVENT_DATA := <dm_version_str> ";" <device_metadata> ";" <active_table_hash> ";" <current_device_capacity> ";"
+
+ dm_version_str := As described in the 'Table load' section above.
+ device_metadata := As described in the 'Table load' section above.
+ active_table_hash := "active_table_hash=" <table_hash_alg> ":" <table_hash>
+                      Rerpresents the hash of the IMA data being measured for the
+                      active table for the device.
+ table_hash_alg := Algorithm used to compute the hash.
+ table_hash := Hash of the (<dm_version_str> ";" <device_metadata> ";" <table_load_data> ";")
+               as described in the 'dm_table_load' above.
+               Note: If the table_load data spans across multiple IMA 'dm_table_load'
+               events for a given device, the hash is computed combining all the event data
+               i.e. (<dm_version_str> ";" <device_metadata> ";" <table_load_data> ";")
+               across all those events.
+ current_device_capacity := "current_device_capacity=" <N>
+
+ For instance, if a linear device is resumed with the following command,
+ #dmsetup resume linear1
+
+ then IMA ASCII measurement log will have an entry with:
+ (converted from ASCII to text for readability)
+
+ 10 56c00cc062ffc24ccd9ac2d67d194af3282b934e ima-buf sha256:e7d12c03b958b4e0e53e7363a06376be88d98a1ac191fdbd3baf5e4b77f329b6
+ dm_device_resume
+ dm_version=4.45.0;
+ name=linear1,uuid=,major=253,minor=0,minor_count=1,num_targets=4;
+ active_table_hash=sha256:4d73481ecce5eadba8ab084640d85bb9ca899af4d0a122989252a76efadc5b72;current_device_capacity=8;
+
+3. Device remove:
+------------------
+When a device is removed, the device information and a sha256 hash of the
+data from an active and inactive table are measured.
+
+The IMA measurement log has the following format for 'dm_device_remove':
+
+::
+
+ EVENT_NAME := "dm_device_remove"
+ EVENT_DATA := <dm_version_str> ";" <device_active_metadata> ";" <device_inactive_metadata> ";"
+               <active_table_hash> "," <inactive_table_hash> "," <remove_all> ";" <current_device_capacity> ";"
+
+ dm_version_str := As described in the 'Table load' section above.
+ device_active_metadata := Device metadata that reflects the currently loaded active table.
+                           The format is same as 'device_metadata' described in the 'Table load' section above.
+ device_inactive_metadata := Device metadata that reflects the inactive table.
+                             The format is same as 'device_metadata' described in the 'Table load' section above.
+ active_table_hash := Hash of the currently loaded active table.
+                      The format is same as 'active_table_hash' described in the 'Device resume' section above.
+ inactive_table_hash :=  Hash of the inactive table.
+                         The format is same as 'active_table_hash' described in the 'Device resume' section above.
+ remove_all := "remove_all=" <yes_no>
+ yes_no := "y" | "n"
+ current_device_capacity := "current_device_capacity=" <N>
+
+ For instance, if a linear device is removed with the following command,
+  #dmsetup remove l1
+
+ then IMA ASCII measurement log will have the following entry:
+ (converted from ASCII to text for readability)
+
+ 10 790e830a3a7a31590824ac0642b3b31c2d0e8b38 ima-buf sha256:ab9f3c959367a8f5d4403d6ce9c3627dadfa8f9f0e7ec7899299782388de3840
+ dm_device_remove
+ dm_version=4.45.0;
+ device_active_metadata=name=l1,uuid=,major=253,minor=2,minor_count=1,num_targets=2;
+ device_inactive_metadata=name=l1,uuid=,major=253,minor=2,minor_count=1,num_targets=1;
+ active_table_hash=sha256:4a7e62efaebfc86af755831998b7db6f59b60d23c9534fb16a4455907957953a,
+ inactive_table_hash=sha256:9d79c175bc2302d55a183e8f50ad4bafd60f7692fd6249e5fd213e2464384b86,remove_all=n;
+ current_device_capacity=2048;
+
+4. Table clear:
+----------------
+When an inactive table is cleared from the device, the device information and a sha256 hash of the
+data from an inactive table are measured.
+
+The IMA measurement log has the following format for 'dm_table_clear':
+
+::
+
+ EVENT_NAME := "dm_table_clear"
+ EVENT_DATA := <dm_version_str> ";" <device_inactive_metadata> ";" <inactive_table_hash> ";" <current_device_capacity> ";"
+
+ dm_version_str := As described in the 'Table load' section above.
+ device_inactive_metadata := Device metadata that was captured during the load time inactive table being cleared.
+                             The format is same as 'device_metadata' described in the 'Table load' section above.
+ inactive_table_hash := Hash of the inactive table being cleared from the device.
+                        The format is same as 'active_table_hash' described in the 'Device resume' section above.
+ current_device_capacity := "current_device_capacity=" <N>
+
+ For instance, if a linear device's inactive table is cleared,
+  #dmsetup clear l1
+
+ then IMA ASCII measurement log will have an entry with:
+ (converted from ASCII to text for readability)
+
+ 10 77d347408f557f68f0041acb0072946bb2367fe5 ima-buf sha256:42f9ca22163fdfa548e6229dece2959bc5ce295c681644240035827ada0e1db5
+ dm_table_clear
+ dm_version=4.45.0;
+ name=l1,uuid=,major=253,minor=2,minor_count=1,num_targets=1;
+ inactive_table_hash=sha256:75c0dc347063bf474d28a9907037eba060bfe39d8847fc0646d75e149045d545;current_device_capacity=1024;
+
+5. Device rename:
+------------------
+When an device's NAME or UUID is changed, the device information and the new NAME and UUID
+are measured.
+
+The IMA measurement log has the following format for 'dm_device_rename':
+
+::
+
+ EVENT_NAME := "dm_device_rename"
+ EVENT_DATA := <dm_version_str> ";" <device_active_metadata> ";" <new_device_name> "," <new_device_uuid> ";" <current_device_capacity> ";"
+
+ dm_version_str := As described in the 'Table load' section above.
+ device_active_metadata := Device metadata that reflects the currently loaded active table.
+                           The format is same as 'device_metadata' described in the 'Table load' section above.
+ new_device_name := "new_name=" <dm-device-name>
+ dm-device-name := Same as <dm-device-name> described in 'Table load' section above
+ new_device_uuid := "new_uuid=" <dm-device-uuid>
+ dm-device-uuid := Same as <dm-device-uuid> described in 'Table load' section above
+ current_device_capacity := "current_device_capacity=" <N>
+
+ E.g 1: if a linear device's name is changed with the following command,
+  #dmsetup rename linear1 --setuuid 1234-5678
+
+ then IMA ASCII measurement log will have an entry with:
+ (converted from ASCII to text for readability)
+
+ 10 8b0423209b4c66ac1523f4c9848c9b51ee332f48 ima-buf sha256:6847b7258134189531db593e9230b257c84f04038b5a18fd2e1473860e0569ac
+ dm_device_rename
+ dm_version=4.45.0;
+ name=linear1,uuid=,major=253,minor=2,minor_count=1,num_targets=1;new_name=linear1,new_uuid=1234-5678;
+ current_device_capacity=1024;
+
+ E.g 2:  if a linear device's name is changed with the following command,
+  # dmsetup rename linear1 linear=2
+
+ then IMA ASCII measurement log will have an entry with:
+ (converted from ASCII to text for readability)
+
+ 10 bef70476b99c2bdf7136fae033aa8627da1bf76f ima-buf sha256:8c6f9f53b9ef9dc8f92a2f2cca8910e622543d0f0d37d484870cb16b95111402
+ dm_device_rename
+ dm_version=4.45.0;
+ name=linear1,uuid=1234-5678,major=253,minor=2,minor_count=1,num_targets=1;
+ new_name=linear\=2,new_uuid=1234-5678;
+ current_device_capacity=1024;
+
+Supported targets:
+==================
+
+Following targets are supported to measure their data using IMA:
+
+ 1. cache
+ #. crypt
+ #. integrity
+ #. linear
+ #. mirror
+ #. multipath
+ #. raid
+ #. snapshot
+ #. striped
+ #. verity
+
+1. cache
+---------
+The 'target_attributes' (described as part of EVENT_DATA in 'Table load'
+section above) has the following data format for 'cache' target.
+
+::
+
+ target_attributes := <target_name> "," <target_version> "," <metadata_mode> "," <cache_metadata_device> ","
+                      <cache_device> "," <cache_origin_device> "," <writethrough> "," <writeback> ","
+                      <passthrough> "," <no_discard_passdown> ";"
+
+ target_name := "target_name=cache"
+ target_version := "target_version=" <N> "." <N> "." <N>
+ metadata_mode := "metadata_mode=" <cache_metadata_mode>
+ cache_metadata_mode := "fail" | "ro" | "rw"
+ cache_device := "cache_device=" <cache_device_name_string>
+ cache_origin_device := "cache_origin_device=" <cache_origin_device_string>
+ writethrough := "writethrough=" <yes_no>
+ writeback := "writeback=" <yes_no>
+ passthrough := "passthrough=" <yes_no>
+ no_discard_passdown := "no_discard_passdown=" <yes_no>
+ yes_no := "y" | "n"
+
+ E.g.
+ When a 'cache' target is loaded, then IMA ASCII measurement log will have an entry
+ similar to the following, depicting what 'cache' attributes are measured in EVENT_DATA
+ for 'dm_table_load' event.
+ (converted from ASCII to text for readability)
+
+ dm_version=4.45.0;name=cache1,uuid=cache_uuid,major=253,minor=2,minor_count=1,num_targets=1;
+ target_index=0,target_begin=0,target_len=28672,target_name=cache,target_version=2.2.0,metadata_mode=rw,
+ cache_metadata_device=253:4,cache_device=253:3,cache_origin_device=253:5,writethrough=y,writeback=n,
+ passthrough=n,metadata2=y,no_discard_passdown=n;
+
+
+2. crypt
+---------
+The 'target_attributes' (described as part of EVENT_DATA in 'Table load'
+section above) has the following data format for 'crypt' target.
+
+::
+
+ target_attributes := <target_name> "," <target_version> "," <allow_discards> "," <same_cpu_crypt> ","
+                      <submit_from_crypt_cpus> "," <no_read_workqueue> "," <no_write_workqueue> ","
+                      <iv_large_sectors> "," <iv_large_sectors> "," [<integrity_tag_size> ","] [<cipher_auth> ","]
+                      [<sector_size> ","] [<cipher_string> ","] <key_size> "," <key_parts> ","
+                      <key_extra_size> "," <key_mac_size> ";"
+
+ target_name := "target_name=crypt"
+ target_version := "target_version=" <N> "." <N> "." <N>
+ allow_discards := "allow_discards=" <yes_no>
+ same_cpu_crypt := "same_cpu_crypt=" <yes_no>
+ submit_from_crypt_cpus := "submit_from_crypt_cpus=" <yes_no>
+ no_read_workqueue := "no_read_workqueue=" <yes_no>
+ no_write_workqueue := "no_write_workqueue=" <yes_no>
+ iv_large_sectors := "iv_large_sectors=" <yes_no>
+ integrity_tag_size := "integrity_tag_size=" <N>
+ cipher_auth := "cipher_auth=" <string>
+ sector_size := "sector_size="  <N>
+ cipher_string := "cipher_string="
+ key_size := "key_size="  <N>
+ key_parts := "key_parts="  <N>
+ key_extra_size := "key_extra_size="  <N>
+ key_mac_size := "key_mac_size="  <N>
+ yes_no := "y" | "n"
+
+ E.g.
+ When a 'crypt' target is loaded, then IMA ASCII measurement log will have an entry
+ similar to the following, depicting what 'crypt' attributes are measured in EVENT_DATA
+ for 'dm_table_load' event.
+ (converted from ASCII to text for readability)
+
+ dm_version=4.45.0;
+ name=crypt1,uuid=crypt_uuid1,major=253,minor=0,minor_count=1,num_targets=1;
+ target_index=0,target_begin=0,target_len=1953125,target_name=crypt,target_version=1.23.0,
+ allow_discards=y,same_cpu=n,submit_from_crypt_cpus=n,no_read_workqueue=n,no_write_workqueue=n,
+ iv_large_sectors=n,cipher_string=aes-xts-plain64,key_size=32,key_parts=1,key_extra_size=0,key_mac_size=0;
+
+3. integrity
+-------------
+The 'target_attributes' (described as part of EVENT_DATA in 'Table load'
+section above) has the following data format for 'integrity' target.
+
+::
+
+ target_attributes := <target_name> "," <target_version> "," <dev_name> "," <start>
+                      <tag_size> "," <mode> "," [<meta_device> ","] [<block_size> ","] <recalculate> ","
+                      <allow_discards> "," <fix_padding> "," <fix_hmac> "," <legacy_recalculate> ","
+                      <journal_sectors> "," <interleave_sectors> "," <buffer_sectors> ";"
+
+ target_name := "target_name=integrity"
+ target_version := "target_version=" <N> "." <N> "." <N>
+ dev_name := "dev_name=" <device_name_str>
+ start := "start=" <N>
+ tag_size := "tag_size=" <N>
+ mode := "mode=" <integrity_mode_str>
+ integrity_mode_str := "J" | "B" | "D" | "R"
+ meta_device := "meta_device=" <meta_device_str>
+ block_size := "block_size=" <N>
+ recalculate := "recalculate=" <yes_no>
+ allow_discards := "allow_discards=" <yes_no>
+ fix_padding := "fix_padding=" <yes_no>
+ fix_hmac := "fix_hmac=" <yes_no>
+ legacy_recalculate := "legacy_recalculate=" <yes_no>
+ journal_sectors := "journal_sectors=" <N>
+ interleave_sectors := "interleave_sectors=" <N>
+ buffer_sectors := "buffer_sectors=" <N>
+ yes_no := "y" | "n"
+
+ E.g.
+ When a 'integrity' target is loaded, then IMA ASCII measurement log will have an entry
+ similar to the following, depicting what 'integrity' attributes are measured in EVENT_DATA
+ for 'dm_table_load' event.
+ (converted from ASCII to text for readability)
+
+ dm_version=4.45.0;
+ name=integrity1,uuid=,major=253,minor=1,minor_count=1,num_targets=1;
+ target_index=0,target_begin=0,target_len=7856,target_name=integrity,target_version=1.10.0,
+ dev_name=253:0,start=0,tag_size=32,mode=J,recalculate=n,allow_discards=n,fix_padding=n,
+ fix_hmac=n,legacy_recalculate=n,journal_sectors=88,interleave_sectors=32768,buffer_sectors=128;
+
+
+4. linear
+----------
+The 'target_attributes' (described as part of EVENT_DATA in 'Table load'
+section above) has the following data format for 'linear' target.
+
+::
+
+ target_attributes := <target_name> "," <target_version> "," <device_name> <,> <start> ";"
+
+ target_name := "target_name=linear"
+ target_version := "target_version=" <N> "." <N> "." <N>
+ device_name := "device_name=" <linear_device_name_str>
+ start := "start=" <N>
+
+ E.g.
+ When a 'linear' target is loaded, then IMA ASCII measurement log will have an entry
+ similar to the following, depicting what 'linear' attributes are measured in EVENT_DATA
+ for 'dm_table_load' event.
+ (converted from ASCII to text for readability)
+
+ dm_version=4.45.0;
+ name=linear1,uuid=linear_uuid1,major=253,minor=2,minor_count=1,num_targets=1;
+ target_index=0,target_begin=0,target_len=28672,target_name=linear,target_version=1.4.0,
+ device_name=253:1,start=2048;
+
+5. mirror
+----------
+The 'target_attributes' (described as part of EVENT_DATA in 'Table load'
+section above) has the following data format for 'mirror' target.
+
+::
+
+ target_attributes := <target_name> "," <target_version> "," <nr_mirrors> ","
+                      <mirror_device_data> "," <handle_errors> "," <keep_log> "," <log_type_status> ";"
+
+ target_name := "target_name=mirror"
+ target_version := "target_version=" <N> "." <N> "." <N>
+ nr_mirrors := "nr_mirrors=" <NR>
+ mirror_device_data := <mirror_device_row> | <mirror_device_data><mirror_device_row>
+                       mirror_device_row is repeated <NR> times - for <NR> described in <nr_mirrors>.
+ mirror_device_row := <mirror_device_name> "," <mirror_device_status>
+ mirror_device_name := "mirror_device_" <X> "=" <mirror_device_name_str>
+                       where <X> ranges from 0 to (<NR> -1) - for <NR> described in <nr_mirrors>.
+ mirror_device_status := "mirror_device_" <X> "_status=" <mirror_device_status_char>
+                         where <X> ranges from 0 to (<NR> -1) - for <NR> described in <nr_mirrors>.
+ mirror_device_status_char := "A" | "F" | "D" | "S" | "R" | "U"
+ handle_errors := "handle_errors=" <yes_no>
+ keep_log := "keep_log=" <yes_no>
+ log_type_status := "log_type_status=" <log_type_status_str>
+ yes_no := "y" | "n"
+
+ E.g.
+ When a 'mirror' target is loaded, then IMA ASCII measurement log will have an entry
+ similar to the following, depicting what 'mirror' attributes are measured in EVENT_DATA
+ for 'dm_table_load' event.
+ (converted from ASCII to text for readability)
+
+ dm_version=4.45.0;
+ name=mirror1,uuid=mirror_uuid1,major=253,minor=6,minor_count=1,num_targets=1;
+ target_index=0,target_begin=0,target_len=2048,target_name=mirror,target_version=1.14.0,nr_mirrors=2,
+    mirror_device_0=253:4,mirror_device_0_status=A,
+    mirror_device_1=253:5,mirror_device_1_status=A,
+ handle_errors=y,keep_log=n,log_type_status=;
+
+6. multipath
+-------------
+The 'target_attributes' (described as part of EVENT_DATA in 'Table load'
+section above) has the following data format for 'multipath' target.
+
+::
+
+ target_attributes := <target_name> "," <target_version> "," <nr_priority_groups>
+                      ["," <pg_state> "," <priority_groups> "," <priority_group_paths>] ";"
+
+ target_name := "target_name=multipath"
+ target_version := "target_version=" <N> "." <N> "." <N>
+ nr_priority_groups := "nr_priority_groups=" <NPG>
+ priority_groups := <priority_groups_row>|<priority_groups_row><priority_groups>
+ priority_groups_row := "pg_state_" <X> "=" <pg_state_str> "," "nr_pgpaths_" <X>  "=" <NPGP> ","
+                        "path_selector_name_" <X> "=" <string> "," <priority_group_paths>
+                        where <X> ranges from 0 to (<NPG> -1) - for <NPG> described in <nr_priority_groups>.
+ pg_state_str := "E" | "A" | "D"
+ <priority_group_paths> := <priority_group_paths_row> | <priority_group_paths_row><priority_group_paths>
+ priority_group_paths_row := "path_name_" <X> "_" <Y> "=" <string> "," "is_active_" <X> "_" <Y> "=" <is_active_str>
+                             "fail_count_" <X> "_" <Y> "=" <N> "," "path_selector_status_" <X> "_" <Y> "=" <path_selector_status_str>
+                             where <X> ranges from 0 to (<NPG> -1) - for <NPG> described in <nr_priority_groups>,
+                             and <Y> ranges from 0 to (<NPGP> -1) - for <NPGP> described in <priority_groups_row>.
+ is_active_str := "A" | "F"
+
+ E.g.
+ When a 'multipath' target is loaded, then IMA ASCII measurement log will have an entry
+ similar to the following, depicting what 'multipath' attributes are measured in EVENT_DATA
+ for 'dm_table_load' event.
+ (converted from ASCII to text for readability)
+
+ dm_version=4.45.0;
+ name=mp,uuid=,major=253,minor=0,minor_count=1,num_targets=1;
+ target_index=0,target_begin=0,target_len=2097152,target_name=multipath,target_version=1.14.0,nr_priority_groups=2,
+    pg_state_0=E,nr_pgpaths_0=2,path_selector_name_0=queue-length,
+        path_name_0_0=8:16,is_active_0_0=A,fail_count_0_0=0,path_selector_status_0_0=,
+        path_name_0_1=8:32,is_active_0_1=A,fail_count_0_1=0,path_selector_status_0_1=,
+    pg_state_1=E,nr_pgpaths_1=2,path_selector_name_1=queue-length,
+        path_name_1_0=8:48,is_active_1_0=A,fail_count_1_0=0,path_selector_status_1_0=,
+        path_name_1_1=8:64,is_active_1_1=A,fail_count_1_1=0,path_selector_status_1_1=;
+
+7. raid
+--------
+The 'target_attributes' (described as part of EVENT_DATA in 'Table load'
+section above) has the following data format for 'raid' target.
+
+::
+
+ target_attributes := <target_name> "," <target_version> "," <raid_type> "," <raid_disks> "," <raid_state>
+                      <raid_device_status> ["," journal_dev_mode] ";"
+
+ target_name := "target_name=raid"
+ target_version := "target_version=" <N> "." <N> "." <N>
+ raid_type := "raid_type=" <raid_type_str>
+ raid_disks := "raid_disks=" <NRD>
+ raid_state := "raid_state=" <raid_state_str>
+ raid_state_str := "frozen" | "reshape" |"resync" | "check" | "repair" | "recover" | "idle" |"undef"
+ raid_device_status := <raid_device_status_row> | <raid_device_status_row><raid_device_status>
+                       <raid_device_status_row> is repeated <NRD> times - for <NRD> described in <raid_disks>.
+ raid_device_status_row := "raid_device_" <X> "_status=" <raid_device_status_str>
+                           where <X> ranges from 0 to (<NRD> -1) - for <NRD> described in <raid_disks>.
+ raid_device_status_str := "A" | "D" | "a" | "-"
+ journal_dev_mode := "journal_dev_mode=" <journal_dev_mode_str>
+ journal_dev_mode_str := "writethrough" | "writeback" | "invalid"
+
+ E.g.
+ When a 'raid' target is loaded, then IMA ASCII measurement log will have an entry
+ similar to the following, depicting what 'raid' attributes are measured in EVENT_DATA
+ for 'dm_table_load' event.
+ (converted from ASCII to text for readability)
+
+ dm_version=4.45.0;
+ name=raid_LV1,uuid=uuid_raid_LV1,major=253,minor=12,minor_count=1,num_targets=1;
+ target_index=0,target_begin=0,target_len=2048,target_name=raid,target_version=1.15.1,
+ raid_type=raid10,raid_disks=4,raid_state=idle,
+    raid_device_0_status=A,
+    raid_device_1_status=A,
+    raid_device_2_status=A,
+    raid_device_3_status=A;
+
+
+8. snapshot
+------------
+The 'target_attributes' (described as part of EVENT_DATA in 'Table load'
+section above) has the following data format for 'snapshot' target.
+
+::
+
+ target_attributes := <target_name> "," <target_version> "," <snap_origin_name> ","
+                      <snap_cow_name> "," <snap_valid> "," <snap_merge_failed> "," <snapshot_overflowed> ";"
+
+ target_name := "target_name=snapshot"
+ target_version := "target_version=" <N> "." <N> "." <N>
+ snap_origin_name := "snap_origin_name=" <string>
+ snap_cow_name := "snap_cow_name=" <string>
+ snap_valid := "snap_valid=" <yes_no>
+ snap_merge_failed := "snap_merge_failed=" <yes_no>
+ snapshot_overflowed := "snapshot_overflowed=" <yes_no>
+ yes_no := "y" | "n"
+
+ E.g.
+ When a 'snapshot' target is loaded, then IMA ASCII measurement log will have an entry
+ similar to the following, depicting what 'snapshot' attributes are measured in EVENT_DATA
+ for 'dm_table_load' event.
+ (converted from ASCII to text for readability)
+
+ dm_version=4.45.0;
+ name=snap1,uuid=snap_uuid1,major=253,minor=13,minor_count=1,num_targets=1;
+ target_index=0,target_begin=0,target_len=4096,target_name=snapshot,target_version=1.16.0,
+ snap_origin_name=253:11,snap_cow_name=253:12,snap_valid=y,snap_merge_failed=n,snapshot_overflowed=n;
+
+9. striped
+-----------
+The 'target_attributes' (described as part of EVENT_DATA in 'Table load'
+section above) has the following data format for 'striped' target.
+
+::
+
+ target_attributes := <target_name> "," <target_version> "," <stripes> "," <chunk_size> ","
+                      <stripe_data> ";"
+
+ target_name := "target_name=striped"
+ target_version := "target_version=" <N> "." <N> "." <N>
+ stripes := "stripes=" <NS>
+ chunk_size := "chunk_size=" <N>
+ stripe_data := <stripe_data_row>|<stripe_data><stripe_data_row>
+ stripe_data_row := <stripe_device_name> "," <stripe_physical_start> "," <stripe_status>
+ stripe_device_name := "stripe_" <X> "_device_name=" <stripe_device_name_str>
+                       where <X> ranges from 0 to (<NS> -1) - for <NS> described in <stripes>.
+ stripe_physical_start := "stripe_" <X> "_physical_start=" <N>
+                           where <X> ranges from 0 to (<NS> -1) - for <NS> described in <stripes>.
+ stripe_status := "stripe_" <X> "_status=" <stripe_status_str>
+                  where <X> ranges from 0 to (<NS> -1) - for <NS> described in <stripes>.
+ stripe_status_str := "D" | "A"
+
+ E.g.
+ When a 'striped' target is loaded, then IMA ASCII measurement log will have an entry
+ similar to the following, depicting what 'striped' attributes are measured in EVENT_DATA
+ for 'dm_table_load' event.
+ (converted from ASCII to text for readability)
+
+ dm_version=4.45.0;
+ name=striped1,uuid=striped_uuid1,major=253,minor=5,minor_count=1,num_targets=1;
+ target_index=0,target_begin=0,target_len=640,target_name=striped,target_version=1.6.0,stripes=2,chunk_size=64,
+    stripe_0_device_name=253:0,stripe_0_physical_start=2048,stripe_0_status=A,
+    stripe_1_device_name=253:3,stripe_1_physical_start=2048,stripe_1_status=A;
+
+10. verity
+----------
+The 'target_attributes' (described as part of EVENT_DATA in 'Table load'
+section above) has the following data format for 'verity' target.
+
+::
+
+ target_attributes := <target_name> "," <target_version> "," <hash_failed> "," <verity_version> ","
+                      <data_device_name> "," <hash_device_name> "," <verity_algorithm> "," <root_digest> ","
+                      <salt> "," <ignore_zero_blocks> "," <check_at_most_once> ["," <root_hash_sig_key_desc>]
+                      ["," <verity_mode>] ";"
+
+ target_name := "target_name=verity"
+ target_version := "target_version=" <N> "." <N> "." <N>
+ hash_failed := "hash_failed=" <hash_failed_str>
+ hash_failed_str := "C" | "V"
+ verity_version := "verity_version=" <verity_version_str>
+ data_device_name := "data_device_name=" <data_device_name_str>
+ hash_device_name := "hash_device_name=" <hash_device_name_str>
+ verity_algorithm := "verity_algorithm=" <verity_algorithm_str>
+ root_digest := "root_digest=" <root_digest_str>
+ salt := "salt=" <salt_str>
+ salt_str := "-" <verity_salt_str>
+ ignore_zero_blocks := "ignore_zero_blocks=" <yes_no>
+ check_at_most_once := "check_at_most_once=" <yes_no>
+ root_hash_sig_key_desc := "root_hash_sig_key_desc="
+ verity_mode := "verity_mode=" <verity_mode_str>
+ verity_mode_str := "ignore_corruption" | "restart_on_corruption" | "panic_on_corruption" | "invalid"
+ yes_no := "y" | "n"
+
+ E.g.
+ When a 'verity' target is loaded, then IMA ASCII measurement log will have an entry
+ similar to the following, depicting what 'verity' attributes are measured in EVENT_DATA
+ for 'dm_table_load' event.
+ (converted from ASCII to text for readability)
+
+ dm_version=4.45.0;
+ name=test-verity,uuid=,major=253,minor=2,minor_count=1,num_targets=1;
+ target_index=0,target_begin=0,target_len=1953120,target_name=verity,target_version=1.8.0,hash_failed=V,
+ verity_version=1,data_device_name=253:1,hash_device_name=253:0,verity_algorithm=sha256,
+ root_digest=29cb87e60ce7b12b443ba6008266f3e41e93e403d7f298f8e3f316b29ff89c5e,
+ salt=e48da609055204e89ae53b655ca2216dd983cf3cb829f34f63a297d106d53e2d,
+ ignore_zero_blocks=n,check_at_most_once=n;
diff --git a/Documentation/admin-guide/device-mapper/index.rst b/Documentation/admin-guide/device-mapper/index.rst
index 6cf8adc86fa8..cde52cc09645 100644
--- a/Documentation/admin-guide/device-mapper/index.rst
+++ b/Documentation/admin-guide/device-mapper/index.rst
@@ -13,6 +13,7 @@ Device Mapper
     dm-dust
     dm-ebs
     dm-flakey
+    dm-ima
     dm-init
     dm-integrity
     dm-io
diff --git a/Documentation/admin-guide/device-mapper/writecache.rst b/Documentation/admin-guide/device-mapper/writecache.rst
index 65427d8dfca6..10429779a91a 100644
--- a/Documentation/admin-guide/device-mapper/writecache.rst
+++ b/Documentation/admin-guide/device-mapper/writecache.rst
@@ -78,13 +78,23 @@ Status:
 2. the number of blocks
 3. the number of free blocks
 4. the number of blocks under writeback
+5. the number of read requests
+6. the number of read requests that hit the cache
+7. the number of write requests
+8. the number of write requests that hit uncommitted block
+9. the number of write requests that hit committed block
+10. the number of write requests that bypass the cache
+11. the number of write requests that are allocated in the cache
+12. the number of write requests that are blocked on the freelist
+13. the number of flush requests
+14. the number of discard requests
 
 Messages:
 	flush
-		flush the cache device. The message returns successfully
+		Flush the cache device. The message returns successfully
 		if the cache device was flushed without an error
 	flush_on_suspend
-		flush the cache device on next suspend. Use this message
+		Flush the cache device on next suspend. Use this message
 		when you are going to remove the cache device. The proper
 		sequence for removing the cache device is:
 
@@ -98,3 +108,5 @@ Messages:
 		6. the cache device is now inactive and it can be deleted
 	cleaner
 		See above "cleaner" constructor documentation.
+	clear_stats
+		Clear the statistics that are reported on the status line