dm vdo: add basic logging and support utilities

Add various support utilities for the vdo target and deduplication index,
including logging utilities, string and time management, and index-specific
error codes.

Co-developed-by: J. corwin Coburn <corwin@hurlbutnet.net>
Signed-off-by: J. corwin Coburn <corwin@hurlbutnet.net>
Co-developed-by: Michael Sclafani <dm-devel@lists.linux.dev>
Signed-off-by: Michael Sclafani <dm-devel@lists.linux.dev>
Co-developed-by: Thomas Jaskiewicz <tom@jaskiewicz.us>
Signed-off-by: Thomas Jaskiewicz <tom@jaskiewicz.us>
Co-developed-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/drivers/md/dm-vdo/errors.h b/drivers/md/dm-vdo/errors.h
new file mode 100644
index 000000000000..0129fa37d8d8
--- /dev/null
+++ b/drivers/md/dm-vdo/errors.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#ifndef UDS_ERRORS_H
+#define UDS_ERRORS_H
+
+#include <linux/compiler.h>
+#include <linux/types.h>
+
+/* Custom error codes and error-related utilities for UDS */
+
+/* Valid status codes for internal UDS functions. */
+enum uds_status_codes {
+	/* Successful return */
+	UDS_SUCCESS = 0,
+
+	/* Used as a base value for reporting internal errors */
+	UDS_ERROR_CODE_BASE = 1024,
+	/* Index overflow */
+	UDS_OVERFLOW = UDS_ERROR_CODE_BASE + 0,
+	/* Invalid argument passed to internal routine */
+	UDS_INVALID_ARGUMENT = UDS_ERROR_CODE_BASE + 1,
+	/* UDS data structures are in an invalid state */
+	UDS_BAD_STATE = UDS_ERROR_CODE_BASE + 2,
+	/* Attempt to enter the same name into an internal structure twice */
+	UDS_DUPLICATE_NAME = UDS_ERROR_CODE_BASE + 3,
+	/* An assertion failed */
+	UDS_ASSERTION_FAILED = UDS_ERROR_CODE_BASE + 4,
+	/* A request has been queued for later processing (not an error) */
+	UDS_QUEUED = UDS_ERROR_CODE_BASE + 5,
+	/* A problem has occurred with a buffer */
+	UDS_BUFFER_ERROR = UDS_ERROR_CODE_BASE + 6,
+	/* No directory was found where one was expected */
+	UDS_NO_DIRECTORY = UDS_ERROR_CODE_BASE + 7,
+	/* This error range has already been registered */
+	UDS_ALREADY_REGISTERED = UDS_ERROR_CODE_BASE + 8,
+	/* Attempt to read or write data outside the valid range */
+	UDS_OUT_OF_RANGE = UDS_ERROR_CODE_BASE + 9,
+	/* Could not load modules */
+	UDS_EMODULE_LOAD = UDS_ERROR_CODE_BASE + 10,
+	/* The index session is disabled */
+	UDS_DISABLED = UDS_ERROR_CODE_BASE + 11,
+	/* Unknown error */
+	UDS_UNKNOWN_ERROR = UDS_ERROR_CODE_BASE + 12,
+	/* The index configuration or volume format is no longer supported */
+	UDS_UNSUPPORTED_VERSION = UDS_ERROR_CODE_BASE + 13,
+	/* Some index structure is corrupt */
+	UDS_CORRUPT_DATA = UDS_ERROR_CODE_BASE + 14,
+	/* No index state found */
+	UDS_NO_INDEX = UDS_ERROR_CODE_BASE + 15,
+	/* Attempt to access incomplete index save data */
+	UDS_INDEX_NOT_SAVED_CLEANLY = UDS_ERROR_CODE_BASE + 16,
+	/* One more than the last UDS_INTERNAL error code */
+	UDS_ERROR_CODE_LAST,
+	/* One more than the last error this block will ever use */
+	UDS_ERROR_CODE_BLOCK_END = UDS_ERROR_CODE_BASE + 440,
+};
+
+enum {
+	UDS_MAX_ERROR_NAME_SIZE = 80,
+	UDS_MAX_ERROR_MESSAGE_SIZE = 128,
+};
+
+struct error_info {
+	const char *name;
+	const char *message;
+};
+
+const char * __must_check uds_string_error(int errnum, char *buf, size_t buflen);
+
+const char *uds_string_error_name(int errnum, char *buf, size_t buflen);
+
+int uds_map_to_system_error(int error);
+
+int uds_register_error_block(const char *block_name, int first_error,
+			     int last_reserved_error, const struct error_info *infos,
+			     size_t info_size);
+
+#endif /* UDS_ERRORS_H */