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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /drivers/md/dm-exception-store.h
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
Diffstat (limited to 'drivers/md/dm-exception-store.h')
-rw-r--r--drivers/md/dm-exception-store.h206
1 files changed, 206 insertions, 0 deletions
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
new file mode 100644
index 000000000..061b4d310
--- /dev/null
+++ b/drivers/md/dm-exception-store.h
@@ -0,0 +1,206 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
+ * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
+ *
+ * Device-mapper snapshot exception store.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _LINUX_DM_EXCEPTION_STORE
+#define _LINUX_DM_EXCEPTION_STORE
+
+#include <linux/blkdev.h>
+#include <linux/list_bl.h>
+#include <linux/device-mapper.h>
+
+/*
+ * The snapshot code deals with largish chunks of the disk at a
+ * time. Typically 32k - 512k.
+ */
+typedef sector_t chunk_t;
+
+/*
+ * An exception is used where an old chunk of data has been
+ * replaced by a new one.
+ * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number
+ * of chunks that follow contiguously. Remaining bits hold the number of the
+ * chunk within the device.
+ */
+struct dm_exception {
+ struct hlist_node hash_list;
+
+ chunk_t old_chunk;
+ chunk_t new_chunk;
+};
+
+/*
+ * Abstraction to handle the meta/layout of exception stores (the
+ * COW device).
+ */
+struct dm_exception_store;
+struct dm_exception_store_type {
+ const char *name;
+ struct module *module;
+
+ int (*ctr)(struct dm_exception_store *store, char *options);
+
+ /*
+ * Destroys this object when you've finished with it.
+ */
+ void (*dtr)(struct dm_exception_store *store);
+
+ /*
+ * The target shouldn't read the COW device until this is
+ * called. As exceptions are read from the COW, they are
+ * reported back via the callback.
+ */
+ int (*read_metadata)(struct dm_exception_store *store,
+ int (*callback)(void *callback_context,
+ chunk_t old, chunk_t new),
+ void *callback_context);
+
+ /*
+ * Find somewhere to store the next exception.
+ */
+ int (*prepare_exception)(struct dm_exception_store *store,
+ struct dm_exception *e);
+
+ /*
+ * Update the metadata with this exception.
+ */
+ void (*commit_exception)(struct dm_exception_store *store,
+ struct dm_exception *e, int valid,
+ void (*callback)(void *, int success),
+ void *callback_context);
+
+ /*
+ * Returns 0 if the exception store is empty.
+ *
+ * If there are exceptions still to be merged, sets
+ * *last_old_chunk and *last_new_chunk to the most recent
+ * still-to-be-merged chunk and returns the number of
+ * consecutive previous ones.
+ */
+ int (*prepare_merge)(struct dm_exception_store *store,
+ chunk_t *last_old_chunk, chunk_t *last_new_chunk);
+
+ /*
+ * Clear the last n exceptions.
+ * nr_merged must be <= the value returned by prepare_merge.
+ */
+ int (*commit_merge)(struct dm_exception_store *store, int nr_merged);
+
+ /*
+ * The snapshot is invalid, note this in the metadata.
+ */
+ void (*drop_snapshot)(struct dm_exception_store *store);
+
+ unsigned int (*status)(struct dm_exception_store *store,
+ status_type_t status, char *result,
+ unsigned int maxlen);
+
+ /*
+ * Return how full the snapshot is.
+ */
+ void (*usage)(struct dm_exception_store *store,
+ sector_t *total_sectors, sector_t *sectors_allocated,
+ sector_t *metadata_sectors);
+
+ /* For internal device-mapper use only. */
+ struct list_head list;
+};
+
+struct dm_snapshot;
+
+struct dm_exception_store {
+ struct dm_exception_store_type *type;
+ struct dm_snapshot *snap;
+
+ /* Size of data blocks saved - must be a power of 2 */
+ unsigned int chunk_size;
+ unsigned int chunk_mask;
+ unsigned int chunk_shift;
+
+ void *context;
+
+ bool userspace_supports_overflow;
+};
+
+/*
+ * Obtain the origin or cow device used by a given snapshot.
+ */
+struct dm_dev *dm_snap_origin(struct dm_snapshot *snap);
+struct dm_dev *dm_snap_cow(struct dm_snapshot *snap);
+
+/*
+ * Funtions to manipulate consecutive chunks
+ */
+#define DM_CHUNK_CONSECUTIVE_BITS 8
+#define DM_CHUNK_NUMBER_BITS 56
+
+static inline chunk_t dm_chunk_number(chunk_t chunk)
+{
+ return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
+}
+
+static inline unsigned int dm_consecutive_chunk_count(struct dm_exception *e)
+{
+ return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_exception *e)
+{
+ e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
+
+ BUG_ON(!dm_consecutive_chunk_count(e));
+}
+
+static inline void dm_consecutive_chunk_count_dec(struct dm_exception *e)
+{
+ BUG_ON(!dm_consecutive_chunk_count(e));
+
+ e->new_chunk -= (1ULL << DM_CHUNK_NUMBER_BITS);
+}
+
+/*
+ * Return the number of sectors in the device.
+ */
+static inline sector_t get_dev_size(struct block_device *bdev)
+{
+ return bdev_nr_sectors(bdev);
+}
+
+static inline chunk_t sector_to_chunk(struct dm_exception_store *store,
+ sector_t sector)
+{
+ return sector >> store->chunk_shift;
+}
+
+int dm_exception_store_type_register(struct dm_exception_store_type *type);
+int dm_exception_store_type_unregister(struct dm_exception_store_type *type);
+
+int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
+ unsigned int chunk_size,
+ char **error);
+
+int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
+ struct dm_snapshot *snap,
+ unsigned int *args_used,
+ struct dm_exception_store **store);
+void dm_exception_store_destroy(struct dm_exception_store *store);
+
+int dm_exception_store_init(void);
+void dm_exception_store_exit(void);
+
+/*
+ * Two exception store implementations.
+ */
+int dm_persistent_snapshot_init(void);
+void dm_persistent_snapshot_exit(void);
+
+int dm_transient_snapshot_init(void);
+void dm_transient_snapshot_exit(void);
+
+#endif /* _LINUX_DM_EXCEPTION_STORE */