Merge tag 'pstore-v4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:
 "This has a large internal refactoring along with several smaller
  fixes.

   - constify compression structures; Bhumika Goyal

   - restore powerpc dumping; Ankit Kumar

   - fix more bugs in the rarely exercises module unloading logic

   - reorganize filesystem locking to fix problems noticed by lockdep

   - refactor internal pstore APIs to make development and review
     easier:
      - improve error reporting
      - add kernel-doc structure and function comments
      - avoid insane argument passing by using a common record
        structure"

* tag 'pstore-v4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (23 commits)
  pstore: Solve lockdep warning by moving inode locks
  pstore: Fix flags to enable dumps on powerpc
  pstore: Remove unused vmalloc.h in pmsg
  pstore: simplify write_user_compat()
  pstore: Remove write_buf() callback
  pstore: Replace arguments for write_buf_user() API
  pstore: Replace arguments for write_buf() API
  pstore: Replace arguments for erase() API
  pstore: Do not duplicate record metadata
  pstore: Allocate records on heap instead of stack
  pstore: Pass record contents instead of copying
  pstore: Always allocate buffer for decompression
  pstore: Replace arguments for write() API
  pstore: Replace arguments for read() API
  pstore: Switch pstore_mkfile to pass record
  pstore: Move record decompression to function
  pstore: Extract common arguments into structure
  pstore: Add kernel-doc for struct pstore_info
  pstore: Improve register_pstore() error reporting
  pstore: Avoid race in module unloading
  ...

arch/powerpc/kernel/nvram_64.c

@@ -389,51 +389,40 @@ static int nvram_pstore_open(struct pstore_info *psi)
 
 /**
  * nvram_pstore_write - pstore write callback for nvram
- * @type:               Type of message logged
- * @reason:             reason behind dump (oops/panic)
- * @id:                 identifier to indicate the write performed
- * @part:               pstore writes data to registered buffer in parts,
- *                      part number will indicate the same.
- * @count:              Indicates oops count
- * @compressed:         Flag to indicate the log is compressed
- * @size:               number of bytes written to the registered buffer
- * @psi:                registered pstore_info structure
+ * @record:             pstore record to write, with @id to be set
  *
  * Called by pstore_dump() when an oops or panic report is logged in the
  * printk buffer.
  * Returns 0 on successful write.
  */
-static int nvram_pstore_write(enum pstore_type_id type,
-				enum kmsg_dump_reason reason,
-				u64 *id, unsigned int part, int count,
-				bool compressed, size_t size,
-				struct pstore_info *psi)
+static int nvram_pstore_write(struct pstore_record *record)
 {
 	int rc;
 	unsigned int err_type = ERR_TYPE_KERNEL_PANIC;
 	struct oops_log_info *oops_hdr = (struct oops_log_info *) oops_buf;
 
 	/* part 1 has the recent messages from printk buffer */
-	if (part > 1 || (type != PSTORE_TYPE_DMESG))
+	if (record->part > 1 || (record->type != PSTORE_TYPE_DMESG))
 		return -1;
 
 	if (clobbering_unread_rtas_event())
 		return -1;
 
 	oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
-	oops_hdr->report_length = cpu_to_be16(size);
+	oops_hdr->report_length = cpu_to_be16(record->size);
 	oops_hdr->timestamp = cpu_to_be64(ktime_get_real_seconds());
 
-	if (compressed)
+	if (record->compressed)
 		err_type = ERR_TYPE_KERNEL_PANIC_GZ;
 
 	rc = nvram_write_os_partition(&oops_log_partition, oops_buf,
-		(int) (sizeof(*oops_hdr) + size), err_type, count);
+		(int) (sizeof(*oops_hdr) + record->size), err_type,
+		record->count);
 
 	if (rc != 0)
 		return rc;
 
-	*id = part;
+	record->id = record->part;
 	return 0;
 }
 
@@ -442,10 +431,7 @@ static int nvram_pstore_write(enum pstore_type_id type,
  * Returns the length of the data we read from each partition.
  * Returns 0 if we've been called before.
  */
-static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
-				int *count, struct timespec *time, char **buf,
-				bool *compressed, ssize_t *ecc_notice_size,
-				struct pstore_info *psi)
+static ssize_t nvram_pstore_read(struct pstore_record *record)
 {
 	struct oops_log_info *oops_hdr;
 	unsigned int err_type, id_no, size = 0;
@@ -459,40 +445,40 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
 	switch (nvram_type_ids[read_type]) {
 	case PSTORE_TYPE_DMESG:
 		part = &oops_log_partition;
-		*type = PSTORE_TYPE_DMESG;
+		record->type = PSTORE_TYPE_DMESG;
 		break;
 	case PSTORE_TYPE_PPC_COMMON:
 		sig = NVRAM_SIG_SYS;
 		part = &common_partition;
-		*type = PSTORE_TYPE_PPC_COMMON;
-		*id = PSTORE_TYPE_PPC_COMMON;
-		time->tv_sec = 0;
-		time->tv_nsec = 0;
+		record->type = PSTORE_TYPE_PPC_COMMON;
+		record->id = PSTORE_TYPE_PPC_COMMON;
+		record->time.tv_sec = 0;
+		record->time.tv_nsec = 0;
 		break;
 #ifdef CONFIG_PPC_PSERIES
 	case PSTORE_TYPE_PPC_RTAS:
 		part = &rtas_log_partition;
-		*type = PSTORE_TYPE_PPC_RTAS;
-		time->tv_sec = last_rtas_event;
-		time->tv_nsec = 0;
+		record->type = PSTORE_TYPE_PPC_RTAS;
+		record->time.tv_sec = last_rtas_event;
+		record->time.tv_nsec = 0;
 		break;
 	case PSTORE_TYPE_PPC_OF:
 		sig = NVRAM_SIG_OF;
 		part = &of_config_partition;
-		*type = PSTORE_TYPE_PPC_OF;
-		*id = PSTORE_TYPE_PPC_OF;
-		time->tv_sec = 0;
-		time->tv_nsec = 0;
+		record->type = PSTORE_TYPE_PPC_OF;
+		record->id = PSTORE_TYPE_PPC_OF;
+		record->time.tv_sec = 0;
+		record->time.tv_nsec = 0;
 		break;
 #endif
 #ifdef CONFIG_PPC_POWERNV
 	case PSTORE_TYPE_PPC_OPAL:
 		sig = NVRAM_SIG_FW;
 		part = &skiboot_partition;
-		*type = PSTORE_TYPE_PPC_OPAL;
-		*id = PSTORE_TYPE_PPC_OPAL;
-		time->tv_sec = 0;
-		time->tv_nsec = 0;
+		record->type = PSTORE_TYPE_PPC_OPAL;
+		record->id = PSTORE_TYPE_PPC_OPAL;
+		record->time.tv_sec = 0;
+		record->time.tv_nsec = 0;
 		break;
 #endif
 	default:
@@ -520,10 +506,10 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
 		return 0;
 	}
 
-	*count = 0;
+	record->count = 0;
 
 	if (part->os_partition)
-		*id = id_no;
+		record->id = id_no;
 
 	if (nvram_type_ids[read_type] == PSTORE_TYPE_DMESG) {
 		size_t length, hdr_size;
@@ -533,34 +519,35 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
 			/* Old format oops header had 2-byte record size */
 			hdr_size = sizeof(u16);
 			length = be16_to_cpu(oops_hdr->version);
-			time->tv_sec = 0;
-			time->tv_nsec = 0;
+			record->time.tv_sec = 0;
+			record->time.tv_nsec = 0;
 		} else {
 			hdr_size = sizeof(*oops_hdr);
 			length = be16_to_cpu(oops_hdr->report_length);
-			time->tv_sec = be64_to_cpu(oops_hdr->timestamp);
-			time->tv_nsec = 0;
+			record->time.tv_sec = be64_to_cpu(oops_hdr->timestamp);
+			record->time.tv_nsec = 0;
 		}
-		*buf = kmemdup(buff + hdr_size, length, GFP_KERNEL);
+		record->buf = kmemdup(buff + hdr_size, length, GFP_KERNEL);
 		kfree(buff);
-		if (*buf == NULL)
+		if (record->buf == NULL)
 			return -ENOMEM;
 
-		*ecc_notice_size = 0;
+		record->ecc_notice_size = 0;
 		if (err_type == ERR_TYPE_KERNEL_PANIC_GZ)
-			*compressed = true;
+			record->compressed = true;
 		else
-			*compressed = false;
+			record->compressed = false;
 		return length;
 	}
 
-	*buf = buff;
+	record->buf = buff;
 	return part->size;
 }
 
 static struct pstore_info nvram_pstore_info = {
 	.owner = THIS_MODULE,
 	.name = "nvram",
+	.flags = PSTORE_FLAGS_DMESG,
 	.open = nvram_pstore_open,
 	.read = nvram_pstore_read,
 	.write = nvram_pstore_write,

drivers/acpi/apei/erst.c

@@ -925,15 +925,9 @@ static int erst_check_table(struct acpi_table_erst *erst_tab)
 
 static int erst_open_pstore(struct pstore_info *psi);
 static int erst_close_pstore(struct pstore_info *psi);
-static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
-			   struct timespec *time, char **buf,
-			   bool *compressed, ssize_t *ecc_notice_size,
-			   struct pstore_info *psi);
-static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
-		       u64 *id, unsigned int part, int count, bool compressed,
-		       size_t size, struct pstore_info *psi);
-static int erst_clearer(enum pstore_type_id type, u64 id, int count,
-			struct timespec time, struct pstore_info *psi);
+static ssize_t erst_reader(struct pstore_record *record);
+static int erst_writer(struct pstore_record *record);
+static int erst_clearer(struct pstore_record *record);
 
 static struct pstore_info erst_info = {
 	.owner		= THIS_MODULE,
@@ -986,10 +980,7 @@ static int erst_close_pstore(struct pstore_info *psi)
 	return 0;
 }
 
-static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
-			   struct timespec *time, char **buf,
-			   bool *compressed, ssize_t *ecc_notice_size,
-			   struct pstore_info *psi)
+static ssize_t erst_reader(struct pstore_record *record)
 {
 	int rc;
 	ssize_t len = 0;
@@ -1027,42 +1018,40 @@ static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
 	if (uuid_le_cmp(rcd->hdr.creator_id, CPER_CREATOR_PSTORE) != 0)
 		goto skip;
 
-	*buf = kmalloc(len, GFP_KERNEL);
-	if (*buf == NULL) {
+	record->buf = kmalloc(len, GFP_KERNEL);
+	if (record->buf == NULL) {
 		rc = -ENOMEM;
 		goto out;
 	}
-	memcpy(*buf, rcd->data, len - sizeof(*rcd));
-	*id = record_id;
-	*compressed = false;
-	*ecc_notice_size = 0;
+	memcpy(record->buf, rcd->data, len - sizeof(*rcd));
+	record->id = record_id;
+	record->compressed = false;
+	record->ecc_notice_size = 0;
 	if (uuid_le_cmp(rcd->sec_hdr.section_type,
 			CPER_SECTION_TYPE_DMESG_Z) == 0) {
-		*type = PSTORE_TYPE_DMESG;
-		*compressed = true;
+		record->type = PSTORE_TYPE_DMESG;
+		record->compressed = true;
 	} else if (uuid_le_cmp(rcd->sec_hdr.section_type,
 			CPER_SECTION_TYPE_DMESG) == 0)
-		*type = PSTORE_TYPE_DMESG;
+		record->type = PSTORE_TYPE_DMESG;
 	else if (uuid_le_cmp(rcd->sec_hdr.section_type,
 			     CPER_SECTION_TYPE_MCE) == 0)
-		*type = PSTORE_TYPE_MCE;
+		record->type = PSTORE_TYPE_MCE;
 	else
-		*type = PSTORE_TYPE_UNKNOWN;
+		record->type = PSTORE_TYPE_UNKNOWN;
 
 	if (rcd->hdr.validation_bits & CPER_VALID_TIMESTAMP)
-		time->tv_sec = rcd->hdr.timestamp;
+		record->time.tv_sec = rcd->hdr.timestamp;
 	else
-		time->tv_sec = 0;
-	time->tv_nsec = 0;
+		record->time.tv_sec = 0;
+	record->time.tv_nsec = 0;
 
 out:
 	kfree(rcd);
 	return (rc < 0) ? rc : (len - sizeof(*rcd));
 }
 
-static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
-		       u64 *id, unsigned int part, int count, bool compressed,
-		       size_t size, struct pstore_info *psi)
+static int erst_writer(struct pstore_record *record)
 {
 	struct cper_pstore_record *rcd = (struct cper_pstore_record *)
 					(erst_info.buf - sizeof(*rcd));
@@ -1077,21 +1066,21 @@ static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
 	/* timestamp valid. platform_id, partition_id are invalid */
 	rcd->hdr.validation_bits = CPER_VALID_TIMESTAMP;
 	rcd->hdr.timestamp = get_seconds();
-	rcd->hdr.record_length = sizeof(*rcd) + size;
+	rcd->hdr.record_length = sizeof(*rcd) + record->size;
 	rcd->hdr.creator_id = CPER_CREATOR_PSTORE;
 	rcd->hdr.notification_type = CPER_NOTIFY_MCE;
 	rcd->hdr.record_id = cper_next_record_id();
 	rcd->hdr.flags = CPER_HW_ERROR_FLAGS_PREVERR;
 
 	rcd->sec_hdr.section_offset = sizeof(*rcd);
-	rcd->sec_hdr.section_length = size;
+	rcd->sec_hdr.section_length = record->size;
 	rcd->sec_hdr.revision = CPER_SEC_REV;
 	/* fru_id and fru_text is invalid */
 	rcd->sec_hdr.validation_bits = 0;
 	rcd->sec_hdr.flags = CPER_SEC_PRIMARY;
-	switch (type) {
+	switch (record->type) {
 	case PSTORE_TYPE_DMESG:
-		if (compressed)
+		if (record->compressed)
 			rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG_Z;
 		else
 			rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG;
@@ -1105,15 +1094,14 @@ static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
 	rcd->sec_hdr.section_severity = CPER_SEV_FATAL;
 
 	ret = erst_write(&rcd->hdr);
-	*id = rcd->hdr.record_id;
+	record->id = rcd->hdr.record_id;
 
 	return ret;
 }
 
-static int erst_clearer(enum pstore_type_id type, u64 id, int count,
-			struct timespec time, struct pstore_info *psi)
+static int erst_clearer(struct pstore_record *record)
 {
-	return erst_clear(id);
+	return erst_clear(record->id);
 }
 
 static int __init erst_init(void)

drivers/firmware/efi/efi-pstore.c

@@ -28,26 +28,16 @@ static int efi_pstore_close(struct pstore_info *psi)
 	return 0;
 }
 
-struct pstore_read_data {
-	u64 *id;
-	enum pstore_type_id *type;
-	int *count;
-	struct timespec *timespec;
-	bool *compressed;
-	ssize_t *ecc_notice_size;
-	char **buf;
-};
-
 static inline u64 generic_id(unsigned long timestamp,
 			     unsigned int part, int count)
 {
 	return ((u64) timestamp * 100 + part) * 1000 + count;
 }
 
-static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
+static int efi_pstore_read_func(struct efivar_entry *entry,
+				struct pstore_record *record)
 {
 	efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
-	struct pstore_read_data *cb_data = data;
 	char name[DUMP_NAME_LEN], data_type;
 	int i;
 	int cnt;
@@ -61,37 +51,37 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
 		name[i] = entry->var.VariableName[i];
 
 	if (sscanf(name, "dump-type%u-%u-%d-%lu-%c",
-		   cb_data->type, &part, &cnt, &time, &data_type) == 5) {
-		*cb_data->id = generic_id(time, part, cnt);
-		*cb_data->count = cnt;
-		cb_data->timespec->tv_sec = time;
-		cb_data->timespec->tv_nsec = 0;
+		   &record->type, &part, &cnt, &time, &data_type) == 5) {
+		record->id = generic_id(time, part, cnt);
+		record->count = cnt;
+		record->time.tv_sec = time;
+		record->time.tv_nsec = 0;
 		if (data_type == 'C')
-			*cb_data->compressed = true;
+			record->compressed = true;
 		else
-			*cb_data->compressed = false;
-		*cb_data->ecc_notice_size = 0;
+			record->compressed = false;
+		record->ecc_notice_size = 0;
 	} else if (sscanf(name, "dump-type%u-%u-%d-%lu",
-		   cb_data->type, &part, &cnt, &time) == 4) {
-		*cb_data->id = generic_id(time, part, cnt);
-		*cb_data->count = cnt;
-		cb_data->timespec->tv_sec = time;
-		cb_data->timespec->tv_nsec = 0;
-		*cb_data->compressed = false;
-		*cb_data->ecc_notice_size = 0;
+		   &record->type, &part, &cnt, &time) == 4) {
+		record->id = generic_id(time, part, cnt);
+		record->count = cnt;
+		record->time.tv_sec = time;
+		record->time.tv_nsec = 0;
+		record->compressed = false;
+		record->ecc_notice_size = 0;
 	} else if (sscanf(name, "dump-type%u-%u-%lu",
-			  cb_data->type, &part, &time) == 3) {
+			  &record->type, &part, &time) == 3) {
 		/*
 		 * Check if an old format,
 		 * which doesn't support holding
 		 * multiple logs, remains.
 		 */
-		*cb_data->id = generic_id(time, part, 0);
-		*cb_data->count = 0;
-		cb_data->timespec->tv_sec = time;
-		cb_data->timespec->tv_nsec = 0;
-		*cb_data->compressed = false;
-		*cb_data->ecc_notice_size = 0;
+		record->id = generic_id(time, part, 0);
+		record->count = 0;
+		record->time.tv_sec = time;
+		record->time.tv_nsec = 0;
+		record->compressed = false;
+		record->ecc_notice_size = 0;
 	} else
 		return 0;
 
@@ -99,7 +89,7 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
 	__efivar_entry_get(entry, &entry->var.Attributes,
 			   &entry->var.DataSize, entry->var.Data);
 	size = entry->var.DataSize;
-	memcpy(*cb_data->buf, entry->var.Data,
+	memcpy(record->buf, entry->var.Data,
 	       (size_t)min_t(unsigned long, EFIVARS_DATA_SIZE_MAX, size));
 
 	return size;
@@ -164,7 +154,7 @@ static int efi_pstore_scan_sysfs_exit(struct efivar_entry *pos,
 /**
  * efi_pstore_sysfs_entry_iter
  *
- * @data: function-specific data to pass to callback
+ * @record: pstore record to pass to callback
  * @pos: entry to begin iterating from
  *
  * You MUST call efivar_enter_iter_begin() before this function, and
@@ -175,7 +165,8 @@ static int efi_pstore_scan_sysfs_exit(struct efivar_entry *pos,
  * the next entry of the last one passed to efi_pstore_read_func().
  * To begin iterating from the beginning of the list @pos must be %NULL.
  */
-static int efi_pstore_sysfs_entry_iter(void *data, struct efivar_entry **pos)
+static int efi_pstore_sysfs_entry_iter(struct pstore_record *record,
+				       struct efivar_entry **pos)
 {
 	struct efivar_entry *entry, *n;
 	struct list_head *head = &efivar_sysfs_list;
@@ -186,7 +177,7 @@ static int efi_pstore_sysfs_entry_iter(void *data, struct efivar_entry **pos)
 		list_for_each_entry_safe(entry, n, head, list) {
 			efi_pstore_scan_sysfs_enter(entry, n, head);
 
-			size = efi_pstore_read_func(entry, data);
+			size = efi_pstore_read_func(entry, record);
 			ret = efi_pstore_scan_sysfs_exit(entry, n, head,
 							 size < 0);
 			if (ret)
@@ -201,7 +192,7 @@ static int efi_pstore_sysfs_entry_iter(void *data, struct efivar_entry **pos)
 	list_for_each_entry_safe_from((*pos), n, head, list) {
 		efi_pstore_scan_sysfs_enter((*pos), n, head);
 
-		size = efi_pstore_read_func((*pos), data);
+		size = efi_pstore_read_func((*pos), record);
 		ret = efi_pstore_scan_sysfs_exit((*pos), n, head, size < 0);
 		if (ret)
 			return ret;
@@ -225,71 +216,57 @@ static int efi_pstore_sysfs_entry_iter(void *data, struct efivar_entry **pos)
  * size < 0: Failed to get data of entry logging via efi_pstore_write(),
  *           and pstore will stop reading entry.
  */
-static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
-			       int *count, struct timespec *timespec,
-			       char **buf, bool *compressed,
-			       ssize_t *ecc_notice_size,
-			       struct pstore_info *psi)
+static ssize_t efi_pstore_read(struct pstore_record *record)
 {
-	struct pstore_read_data data;
+	struct efivar_entry *entry = (struct efivar_entry *)record->psi->data;
 	ssize_t size;
 
-	data.id = id;
-	data.type = type;
-	data.count = count;
-	data.timespec = timespec;
-	data.compressed = compressed;
-	data.ecc_notice_size = ecc_notice_size;
-	data.buf = buf;
-
-	*data.buf = kzalloc(EFIVARS_DATA_SIZE_MAX, GFP_KERNEL);
-	if (!*data.buf)
+	record->buf = kzalloc(EFIVARS_DATA_SIZE_MAX, GFP_KERNEL);
+	if (!record->buf)
 		return -ENOMEM;
 
 	if (efivar_entry_iter_begin()) {
-		kfree(*data.buf);
-		return -EINTR;
+		size = -EINTR;
+		goto out;
 	}
-	size = efi_pstore_sysfs_entry_iter(&data,
-					   (struct efivar_entry **)&psi->data);
+	size = efi_pstore_sysfs_entry_iter(record, &entry);
 	efivar_entry_iter_end();
-	if (size <= 0)
-		kfree(*data.buf);
+
+out:
+	if (size <= 0) {
+		kfree(record->buf);
+		record->buf = NULL;
+	}
 	return size;
 }
 
-static int efi_pstore_write(enum pstore_type_id type,
-		enum kmsg_dump_reason reason, u64 *id,
-		unsigned int part, int count, bool compressed, size_t size,
-		struct pstore_info *psi)
+static int efi_pstore_write(struct pstore_record *record)
 {
 	char name[DUMP_NAME_LEN];
 	efi_char16_t efi_name[DUMP_NAME_LEN];
 	efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 	int i, ret = 0;
 
-	sprintf(name, "dump-type%u-%u-%d-%lu-%c", type, part, count,
-		get_seconds(), compressed ? 'C' : 'D');
+	snprintf(name, sizeof(name), "dump-type%u-%u-%d-%lu-%c",
+		 record->type, record->part, record->count,
+		 get_seconds(), record->compressed ? 'C' : 'D');
 
 	for (i = 0; i < DUMP_NAME_LEN; i++)
 		efi_name[i] = name[i];
 
 	ret = efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES,
-				    !pstore_cannot_block_path(reason),
-				    size, psi->buf);
+			      !pstore_cannot_block_path(record->reason),
+			      record->size, record->psi->buf);
 
-	if (reason == KMSG_DUMP_OOPS)
+	if (record->reason == KMSG_DUMP_OOPS)
 		efivar_run_worker();
 
-	*id = part;
+	record->id = record->part;
 	return ret;
 };
 
 struct pstore_erase_data {
-	u64 id;
-	enum pstore_type_id type;
-	int count;
-	struct timespec time;
+	struct pstore_record *record;
 	efi_char16_t *name;
 };
 
@@ -315,8 +292,9 @@ static int efi_pstore_erase_func(struct efivar_entry *entry, void *data)
 		 * Check if an old format, which doesn't support
 		 * holding multiple logs, remains.
 		 */
-		sprintf(name_old, "dump-type%u-%u-%lu", ed->type,
-			(unsigned int)ed->id, ed->time.tv_sec);
+		snprintf(name_old, sizeof(name_old), "dump-type%u-%u-%lu",
+			ed->record->type, (unsigned int)ed->record->id,
+			ed->record->time.tv_sec);
 
 		for (i = 0; i < DUMP_NAME_LEN; i++)
 			efi_name_old[i] = name_old[i];
@@ -341,8 +319,7 @@ static int efi_pstore_erase_func(struct efivar_entry *entry, void *data)
 	return 1;
 }
 
-static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
-			    struct timespec time, struct pstore_info *psi)
+static int efi_pstore_erase(struct pstore_record *record)
 {
 	struct pstore_erase_data edata;
 	struct efivar_entry *entry = NULL;
@@ -351,17 +328,16 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
 	int found, i;
 	unsigned int part;
 
-	do_div(id, 1000);
-	part = do_div(id, 100);
-	sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count, time.tv_sec);
+	do_div(record->id, 1000);
+	part = do_div(record->id, 100);
+	snprintf(name, sizeof(name), "dump-type%u-%u-%d-%lu",
+		 record->type, record->part, record->count,
+		 record->time.tv_sec);
 
 	for (i = 0; i < DUMP_NAME_LEN; i++)
 		efi_name[i] = name[i];
 
-	edata.id = part;
-	edata.type = type;
-	edata.count = count;
-	edata.time = time;
+	edata.record = record;
 	edata.name = efi_name;
 
 	if (efivar_entry_iter_begin())

fs/pstore/ftrace.c

@@ -37,6 +37,12 @@ static void notrace pstore_ftrace_call(unsigned long ip,
 {
 	unsigned long flags;
 	struct pstore_ftrace_record rec = {};
+	struct pstore_record record = {
+		.type = PSTORE_TYPE_FTRACE,
+		.buf = (char *)&rec,
+		.size = sizeof(rec),
+		.psi = psinfo,
+	};
 
 	if (unlikely(oops_in_progress))
 		return;
@@ -47,8 +53,7 @@ static void notrace pstore_ftrace_call(unsigned long ip,
 	rec.parent_ip = parent_ip;
 	pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);
 	pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
-	psinfo->write_buf(PSTORE_TYPE_FTRACE, 0, NULL, 0, (void *)&rec,
-			  0, sizeof(rec), psinfo);
+	psinfo->write(&record);
 
 	local_irq_restore(flags);
 }
@@ -117,7 +122,7 @@ void pstore_register_ftrace(void)
 {
 	struct dentry *file;
 
-	if (!psinfo->write_buf)
+	if (!psinfo->write)
 		return;
 
 	pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);

fs/pstore/inode.c

@@ -47,12 +47,8 @@ static LIST_HEAD(allpstore);
 
 struct pstore_private {
 	struct list_head list;
-	struct pstore_info *psi;
-	enum pstore_type_id type;
-	u64	id;
-	int	count;
-	ssize_t	size;
-	char	data[];
+	struct pstore_record *record;
+	size_t total_size;
 };
 
 struct pstore_ftrace_seq_data {
@@ -63,6 +59,17 @@ struct pstore_ftrace_seq_data {
 
 #define REC_SIZE sizeof(struct pstore_ftrace_record)
 
+static void free_pstore_private(struct pstore_private *private)
+{
+	if (!private)
+		return;
+	if (private->record) {
+		kfree(private->record->buf);
+		kfree(private->record);
+	}
+	kfree(private);
+}
+
 static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
 {
 	struct pstore_private *ps = s->private;
@@ -72,9 +79,9 @@ static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
 	if (!data)
 		return NULL;
 
-	data->off = ps->size % REC_SIZE;
+	data->off = ps->total_size % REC_SIZE;
 	data->off += *pos * REC_SIZE;
-	if (data->off + REC_SIZE > ps->size) {
+	if (data->off + REC_SIZE > ps->total_size) {
 		kfree(data);
 		return NULL;
 	}
@@ -94,7 +101,7 @@ static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
 	struct pstore_ftrace_seq_data *data = v;
 
 	data->off += REC_SIZE;
-	if (data->off + REC_SIZE > ps->size)
+	if (data->off + REC_SIZE > ps->total_size)
 		return NULL;
 
 	(*pos)++;
@@ -105,7 +112,9 @@ static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
 {
 	struct pstore_private *ps = s->private;
 	struct pstore_ftrace_seq_data *data = v;
-	struct pstore_ftrace_record *rec = (void *)(ps->data + data->off);
+	struct pstore_ftrace_record *rec;
+
+	rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
 
 	seq_printf(s, "CPU:%d ts:%llu %08lx  %08lx  %pf <- %pF\n",
 		   pstore_ftrace_decode_cpu(rec),
@@ -125,7 +134,7 @@ static const struct seq_operations pstore_ftrace_seq_ops = {
 
 static int pstore_check_syslog_permissions(struct pstore_private *ps)
 {
-	switch (ps->type) {
+	switch (ps->record->type) {
 	case PSTORE_TYPE_DMESG:
 	case PSTORE_TYPE_CONSOLE:
 		return check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
@@ -141,9 +150,10 @@ static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
 	struct seq_file *sf = file->private_data;
 	struct pstore_private *ps = sf->private;
 
-	if (ps->type == PSTORE_TYPE_FTRACE)
+	if (ps->record->type == PSTORE_TYPE_FTRACE)
 		return seq_read(file, userbuf, count, ppos);
-	return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
+	return simple_read_from_buffer(userbuf, count, ppos,
+				       ps->record->buf, ps->total_size);
 }
 
 static int pstore_file_open(struct inode *inode, struct file *file)
@@ -157,7 +167,7 @@ static int pstore_file_open(struct inode *inode, struct file *file)
 	if (err)
 		return err;
 
-	if (ps->type == PSTORE_TYPE_FTRACE)
+	if (ps->record->type == PSTORE_TYPE_FTRACE)
 		sops = &pstore_ftrace_seq_ops;
 
 	err = seq_open(file, sops);
@@ -193,20 +203,19 @@ static const struct file_operations pstore_file_operations = {
 static int pstore_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct pstore_private *p = d_inode(dentry)->i_private;
+	struct pstore_record *record = p->record;
 	int err;
 
 	err = pstore_check_syslog_permissions(p);
 	if (err)
 		return err;
 
-	if (p->psi->erase) {
-		mutex_lock(&p->psi->read_mutex);
-		p->psi->erase(p->type, p->id, p->count,
-			      d_inode(dentry)->i_ctime, p->psi);
-		mutex_unlock(&p->psi->read_mutex);
-	} else {
+	if (!record->psi->erase)
 		return -EPERM;
-	}
+
+	mutex_lock(&record->psi->read_mutex);
+	record->psi->erase(record);
+	mutex_unlock(&record->psi->read_mutex);
 
 	return simple_unlink(dir, dentry);
 }
@@ -221,7 +230,7 @@ static void pstore_evict_inode(struct inode *inode)
 		spin_lock_irqsave(&allpstore_lock, flags);
 		list_del(&p->list);
 		spin_unlock_irqrestore(&allpstore_lock, flags);
-		kfree(p);
+		free_pstore_private(p);
 	}
 }
 
@@ -302,23 +311,23 @@ bool pstore_is_mounted(void)
  * Load it up with "size" bytes of data from "buf".
  * Set the mtime & ctime to the date that this record was originally stored.
  */
-int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
-		  char *data, bool compressed, size_t size,
-		  struct timespec time, struct pstore_info *psi)
+int pstore_mkfile(struct dentry *root, struct pstore_record *record)
 {
-	struct dentry		*root = pstore_sb->s_root;
 	struct dentry		*dentry;
 	struct inode		*inode;
 	int			rc = 0;
 	char			name[PSTORE_NAMELEN];
 	struct pstore_private	*private, *pos;
 	unsigned long		flags;
+	size_t			size = record->size + record->ecc_notice_size;
+
+	WARN_ON(!inode_is_locked(d_inode(root)));
 
 	spin_lock_irqsave(&allpstore_lock, flags);
 	list_for_each_entry(pos, &allpstore, list) {
-		if (pos->type == type &&
-		    pos->id == id &&
-		    pos->psi == psi) {
+		if (pos->record->type == record->type &&
+		    pos->record->id == record->id &&
+		    pos->record->psi == record->psi) {
 			rc = -EEXIST;
 			break;
 		}
@@ -328,72 +337,74 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
 		return rc;
 
 	rc = -ENOMEM;
-	inode = pstore_get_inode(pstore_sb);
+	inode = pstore_get_inode(root->d_sb);
 	if (!inode)
 		goto fail;
 	inode->i_mode = S_IFREG | 0444;
 	inode->i_fop = &pstore_file_operations;
-	private = kmalloc(sizeof *private + size, GFP_KERNEL);
+	private = kzalloc(sizeof(*private), GFP_KERNEL);
 	if (!private)
 		goto fail_alloc;
-	private->type = type;
-	private->id = id;
-	private->count = count;
-	private->psi = psi;
+	private->record = record;
 
-	switch (type) {
+	switch (record->type) {
 	case PSTORE_TYPE_DMESG:
 		scnprintf(name, sizeof(name), "dmesg-%s-%lld%s",
-			  psname, id, compressed ? ".enc.z" : "");
+			  record->psi->name, record->id,
+			  record->compressed ? ".enc.z" : "");
 		break;
 	case PSTORE_TYPE_CONSOLE:
-		scnprintf(name, sizeof(name), "console-%s-%lld", psname, id);
+		scnprintf(name, sizeof(name), "console-%s-%lld",
+			  record->psi->name, record->id);
 		break;
 	case PSTORE_TYPE_FTRACE:
-		scnprintf(name, sizeof(name), "ftrace-%s-%lld", psname, id);
+		scnprintf(name, sizeof(name), "ftrace-%s-%lld",
+			  record->psi->name, record->id);
 		break;
 	case PSTORE_TYPE_MCE:
-		scnprintf(name, sizeof(name), "mce-%s-%lld", psname, id);
+		scnprintf(name, sizeof(name), "mce-%s-%lld",
+			  record->psi->name, record->id);
 		break;
 	case PSTORE_TYPE_PPC_RTAS:
-		scnprintf(name, sizeof(name), "rtas-%s-%lld", psname, id);
+		scnprintf(name, sizeof(name), "rtas-%s-%lld",
+			  record->psi->name, record->id);
 		break;
 	case PSTORE_TYPE_PPC_OF:
 		scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld",
-			  psname, id);
+			  record->psi->name, record->id);
 		break;
 	case PSTORE_TYPE_PPC_COMMON:
 		scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
-			  psname, id);
+			  record->psi->name, record->id);
 		break;
 	case PSTORE_TYPE_PMSG:
-		scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id);
+		scnprintf(name, sizeof(name), "pmsg-%s-%lld",
+			  record->psi->name, record->id);
 		break;
 	case PSTORE_TYPE_PPC_OPAL:
-		sprintf(name, "powerpc-opal-%s-%lld", psname, id);
+		scnprintf(name, sizeof(name), "powerpc-opal-%s-%lld",
+			  record->psi->name, record->id);
 		break;
 	case PSTORE_TYPE_UNKNOWN:
-		scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id);
+		scnprintf(name, sizeof(name), "unknown-%s-%lld",
+			  record->psi->name, record->id);
 		break;
 	default:
 		scnprintf(name, sizeof(name), "type%d-%s-%lld",
-			  type, psname, id);
+			  record->type, record->psi->name, record->id);
 		break;
 	}
 
-	inode_lock(d_inode(root));
-
 	dentry = d_alloc_name(root, name);
 	if (!dentry)
-		goto fail_lockedalloc;
+		goto fail_private;
 
-	memcpy(private->data, data, size);
-	inode->i_size = private->size = size;
+	inode->i_size = private->total_size = size;
 
 	inode->i_private = private;
 
-	if (time.tv_sec)
-		inode->i_mtime = inode->i_ctime = time;
+	if (record->time.tv_sec)
+		inode->i_mtime = inode->i_ctime = record->time;
 
 	d_add(dentry, inode);
 
@@ -401,13 +412,10 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
 	list_add(&private->list, &allpstore);
 	spin_unlock_irqrestore(&allpstore_lock, flags);
 
-	inode_unlock(d_inode(root));
-
 	return 0;
 
-fail_lockedalloc:
-	inode_unlock(d_inode(root));
-	kfree(private);
+fail_private:
+	free_pstore_private(private);
 fail_alloc:
 	iput(inode);
 
@@ -415,6 +423,27 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
 	return rc;
 }
 
+/*
+ * Read all the records from the persistent store. Create
+ * files in our filesystem.  Don't warn about -EEXIST errors
+ * when we are re-scanning the backing store looking to add new
+ * error records.
+ */
+void pstore_get_records(int quiet)
+{
+	struct pstore_info *psi = psinfo;
+	struct dentry *root;
+
+	if (!psi || !pstore_sb)
+		return;
+
+	root = pstore_sb->s_root;
+
+	inode_lock(d_inode(root));
+	pstore_get_backend_records(psi, root, quiet);
+	inode_unlock(d_inode(root));
+}
+
 static int pstore_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct inode *inode;

fs/pstore/internal.h

@@ -25,10 +25,10 @@ extern struct pstore_info *psinfo;
 
 extern void	pstore_set_kmsg_bytes(int);
 extern void	pstore_get_records(int);
-extern int	pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
-			      int count, char *data, bool compressed,
-			      size_t size, struct timespec time,
-			      struct pstore_info *psi);
+extern void	pstore_get_backend_records(struct pstore_info *psi,
+					   struct dentry *root, int quiet);
+extern int	pstore_mkfile(struct dentry *root,
+			      struct pstore_record *record);
 extern bool	pstore_is_mounted(void);
 
 #endif

fs/pstore/pmsg.c

@@ -15,7 +15,6 @@
 #include <linux/device.h>
 #include <linux/fs.h>
 #include <linux/uaccess.h>
-#include <linux/vmalloc.h>
 #include "internal.h"
 
 static DEFINE_MUTEX(pmsg_lock);
@@ -23,19 +22,22 @@ static DEFINE_MUTEX(pmsg_lock);
 static ssize_t write_pmsg(struct file *file, const char __user *buf,
 			  size_t count, loff_t *ppos)
 {
-	u64 id;
+	struct pstore_record record = {
+		.type = PSTORE_TYPE_PMSG,
+		.size = count,
+		.psi = psinfo,
+	};
 	int ret;
 
 	if (!count)
 		return 0;
 
-	/* check outside lock, page in any data. write_buf_user also checks */
+	/* check outside lock, page in any data. write_user also checks */
 	if (!access_ok(VERIFY_READ, buf, count))
 		return -EFAULT;
 
 	mutex_lock(&pmsg_lock);
-	ret = psinfo->write_buf_user(PSTORE_TYPE_PMSG, 0, &id, 0, buf, 0, count,
-				     psinfo);
+	ret = psinfo->write_user(&record, buf);
 	mutex_unlock(&pmsg_lock);
 	return ret ? ret : count;
 }

fs/pstore/ram.c

@@ -235,35 +235,34 @@ static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest,
 	return 0;
 }
 
-static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
-				   int *count, struct timespec *time,
-				   char **buf, bool *compressed,
-				   ssize_t *ecc_notice_size,
-				   struct pstore_info *psi)
+static ssize_t ramoops_pstore_read(struct pstore_record *record)
 {
 	ssize_t size = 0;
-	struct ramoops_context *cxt = psi->data;
+	struct ramoops_context *cxt = record->psi->data;
 	struct persistent_ram_zone *prz = NULL;
 	int header_length = 0;
 	bool free_prz = false;
 
-	/* Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
+	/*
+	 * Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
 	 * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
 	 * valid time stamps, so it is initialized to zero.
 	 */
-	time->tv_sec = 0;
-	time->tv_nsec = 0;
-	*compressed = false;
+	record->time.tv_sec = 0;
+	record->time.tv_nsec = 0;
+	record->compressed = false;
 
 	/* Find the next valid persistent_ram_zone for DMESG */
 	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
 		prz = ramoops_get_next_prz(cxt->dprzs, &cxt->dump_read_cnt,
-					   cxt->max_dump_cnt, id, type,
+					   cxt->max_dump_cnt, &record->id,
+					   &record->type,
 					   PSTORE_TYPE_DMESG, 1);
 		if (!prz_ok(prz))
 			continue;
 		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
-						      time, compressed);
+						      &record->time,
+						      &record->compressed);
 		/* Clear and skip this DMESG record if it has no valid header */
 		if (!header_length) {
 			persistent_ram_free_old(prz);
@@ -274,18 +273,20 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 
 	if (!prz_ok(prz))
 		prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
-					   1, id, type, PSTORE_TYPE_CONSOLE, 0);
+					   1, &record->id, &record->type,
+					   PSTORE_TYPE_CONSOLE, 0);
 
 	if (!prz_ok(prz))
 		prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
-					   1, id, type, PSTORE_TYPE_PMSG, 0);
+					   1, &record->id, &record->type,
+					   PSTORE_TYPE_PMSG, 0);
 
 	/* ftrace is last since it may want to dynamically allocate memory. */
 	if (!prz_ok(prz)) {
 		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) {
 			prz = ramoops_get_next_prz(cxt->fprzs,
-					&cxt->ftrace_read_cnt, 1, id, type,
-					PSTORE_TYPE_FTRACE, 0);
+					&cxt->ftrace_read_cnt, 1, &record->id,
+					&record->type, PSTORE_TYPE_FTRACE, 0);
 		} else {
 			/*
 			 * Build a new dummy record which combines all the
@@ -302,8 +303,10 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
 				prz_next = ramoops_get_next_prz(cxt->fprzs,
 						&cxt->ftrace_read_cnt,
-						cxt->max_ftrace_cnt, id,
-						type, PSTORE_TYPE_FTRACE, 0);
+						cxt->max_ftrace_cnt,
+						&record->id,
+						&record->type,
+						PSTORE_TYPE_FTRACE, 0);
 
 				if (!prz_ok(prz_next))
 					continue;
@@ -316,7 +319,7 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 				if (size)
 					goto out;
 			}
-			*id = 0;
+			record->id = 0;
 			prz = tmp_prz;
 		}
 	}
@@ -329,17 +332,19 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 	size = persistent_ram_old_size(prz) - header_length;
 
 	/* ECC correction notice */
-	*ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
+	record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
 
-	*buf = kmalloc(size + *ecc_notice_size + 1, GFP_KERNEL);
-	if (*buf == NULL) {
+	record->buf = kmalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
+	if (record->buf == NULL) {
 		size = -ENOMEM;
 		goto out;
 	}
 
-	memcpy(*buf, (char *)persistent_ram_old(prz) + header_length, size);
+	memcpy(record->buf, (char *)persistent_ram_old(prz) + header_length,
+	       size);
 
-	persistent_ram_ecc_string(prz, *buf + size, *ecc_notice_size + 1);
+	persistent_ram_ecc_string(prz, record->buf + size,
+				  record->ecc_notice_size + 1);
 
 out:
 	if (free_prz) {
@@ -373,23 +378,18 @@ static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
 	return len;
 }
 
-static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
-					    enum kmsg_dump_reason reason,
-					    u64 *id, unsigned int part,
-					    const char *buf,
-					    bool compressed, size_t size,
-					    struct pstore_info *psi)
+static int notrace ramoops_pstore_write(struct pstore_record *record)
 {
-	struct ramoops_context *cxt = psi->data;
+	struct ramoops_context *cxt = record->psi->data;
 	struct persistent_ram_zone *prz;
-	size_t hlen;
+	size_t size, hlen;
 
-	if (type == PSTORE_TYPE_CONSOLE) {
+	if (record->type == PSTORE_TYPE_CONSOLE) {
 		if (!cxt->cprz)
 			return -ENOMEM;
-		persistent_ram_write(cxt->cprz, buf, size);
+		persistent_ram_write(cxt->cprz, record->buf, record->size);
 		return 0;
-	} else if (type == PSTORE_TYPE_FTRACE) {
+	} else if (record->type == PSTORE_TYPE_FTRACE) {
 		int zonenum;
 
 		if (!cxt->fprzs)
@@ -402,33 +402,36 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
 		else
 			zonenum = 0;
 
-		persistent_ram_write(cxt->fprzs[zonenum], buf, size);
+		persistent_ram_write(cxt->fprzs[zonenum], record->buf,
+				     record->size);
 		return 0;
-	} else if (type == PSTORE_TYPE_PMSG) {
+	} else if (record->type == PSTORE_TYPE_PMSG) {
 		pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
 		return -EINVAL;
 	}
 
-	if (type != PSTORE_TYPE_DMESG)
+	if (record->type != PSTORE_TYPE_DMESG)
 		return -EINVAL;
 
-	/* Out of the various dmesg dump types, ramoops is currently designed
+	/*
+	 * Out of the various dmesg dump types, ramoops is currently designed
 	 * to only store crash logs, rather than storing general kernel logs.
 	 */
-	if (reason != KMSG_DUMP_OOPS &&
-	    reason != KMSG_DUMP_PANIC)
+	if (record->reason != KMSG_DUMP_OOPS &&
+	    record->reason != KMSG_DUMP_PANIC)
 		return -EINVAL;
 
 	/* Skip Oopes when configured to do so. */
-	if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
+	if (record->reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 		return -EINVAL;
 
-	/* Explicitly only take the first part of any new crash.
+	/*
+	 * Explicitly only take the first part of any new crash.
 	 * If our buffer is larger than kmsg_bytes, this can never happen,
 	 * and if our buffer is smaller than kmsg_bytes, we don't want the
 	 * report split across multiple records.
 	 */
-	if (part != 1)
+	if (record->part != 1)
 		return -ENOSPC;
 
 	if (!cxt->dprzs)
@@ -436,53 +439,50 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
 
 	prz = cxt->dprzs[cxt->dump_write_cnt];
 
-	hlen = ramoops_write_kmsg_hdr(prz, compressed);
+	/* Build header and append record contents. */
+	hlen = ramoops_write_kmsg_hdr(prz, record->compressed);
+	size = record->size;
 	if (size + hlen > prz->buffer_size)
 		size = prz->buffer_size - hlen;
-	persistent_ram_write(prz, buf, size);
+	persistent_ram_write(prz, record->buf, size);
 
 	cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 
 	return 0;
 }
 
-static int notrace ramoops_pstore_write_buf_user(enum pstore_type_id type,
-						 enum kmsg_dump_reason reason,
-						 u64 *id, unsigned int part,
-						 const char __user *buf,
-						 bool compressed, size_t size,
-						 struct pstore_info *psi)
+static int notrace ramoops_pstore_write_user(struct pstore_record *record,
+					     const char __user *buf)
 {
-	if (type == PSTORE_TYPE_PMSG) {
-		struct ramoops_context *cxt = psi->data;
+	if (record->type == PSTORE_TYPE_PMSG) {
+		struct ramoops_context *cxt = record->psi->data;
 
 		if (!cxt->mprz)
 			return -ENOMEM;
-		return persistent_ram_write_user(cxt->mprz, buf, size);
+		return persistent_ram_write_user(cxt->mprz, buf, record->size);
 	}
 
 	return -EINVAL;
 }
 
-static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
-				struct timespec time, struct pstore_info *psi)
+static int ramoops_pstore_erase(struct pstore_record *record)
 {
-	struct ramoops_context *cxt = psi->data;
+	struct ramoops_context *cxt = record->psi->data;
 	struct persistent_ram_zone *prz;
 
-	switch (type) {
+	switch (record->type) {
 	case PSTORE_TYPE_DMESG:
-		if (id >= cxt->max_dump_cnt)
+		if (record->id >= cxt->max_dump_cnt)
 			return -EINVAL;
-		prz = cxt->dprzs[id];
+		prz = cxt->dprzs[record->id];
 		break;
 	case PSTORE_TYPE_CONSOLE:
 		prz = cxt->cprz;
 		break;
 	case PSTORE_TYPE_FTRACE:
-		if (id >= cxt->max_ftrace_cnt)
+		if (record->id >= cxt->max_ftrace_cnt)
 			return -EINVAL;
-		prz = cxt->fprzs[id];
+		prz = cxt->fprzs[record->id];
 		break;
 	case PSTORE_TYPE_PMSG:
 		prz = cxt->mprz;
@@ -503,8 +503,8 @@ static struct ramoops_context oops_cxt = {
 		.name	= "ramoops",
 		.open	= ramoops_pstore_open,
 		.read	= ramoops_pstore_read,
-		.write_buf	= ramoops_pstore_write_buf,
-		.write_buf_user	= ramoops_pstore_write_buf_user,
+		.write	= ramoops_pstore_write,
+		.write_user	= ramoops_pstore_write_user,
 		.erase	= ramoops_pstore_erase,
 	},
 };

fs/pstore/ram_core.c

@@ -532,7 +532,7 @@ struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 	}
 
 	/* Initialize general buffer state. */
-	prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock);
+	raw_spin_lock_init(&prz->buffer_lock);
 	prz->flags = flags;
 
 	ret = persistent_ram_buffer_map(start, size, prz, memtype);

include/linux/pstore.h

@@ -30,7 +30,9 @@
 #include <linux/time.h>
 #include <linux/types.h>
 
-/* types */
+struct module;
+
+/* pstore record types (see fs/pstore/inode.c for filename templates) */
 enum pstore_type_id {
 	PSTORE_TYPE_DMESG	= 0,
 	PSTORE_TYPE_MCE		= 1,
@@ -45,42 +47,146 @@ enum pstore_type_id {
 	PSTORE_TYPE_UNKNOWN	= 255
 };
 
-struct module;
+struct pstore_info;
+/**
+ * struct pstore_record - details of a pstore record entry
+ * @psi:	pstore backend driver information
+ * @type:	pstore record type
+ * @id:		per-type unique identifier for record
+ * @time:	timestamp of the record
+ * @buf:	pointer to record contents
+ * @size:	size of @buf
+ * @ecc_notice_size:
+ *		ECC information for @buf
+ *
+ * Valid for PSTORE_TYPE_DMESG @type:
+ *
+ * @count:	Oops count since boot
+ * @reason:	kdump reason for notification
+ * @part:	position in a multipart record
+ * @compressed:	whether the buffer is compressed
+ *
+ */
+struct pstore_record {
+	struct pstore_info	*psi;
+	enum pstore_type_id	type;
+	u64			id;
+	struct timespec		time;
+	char			*buf;
+	ssize_t			size;
+	ssize_t			ecc_notice_size;
 
+	int			count;
+	enum kmsg_dump_reason	reason;
+	unsigned int		part;
+	bool			compressed;
+};
+
+/**
+ * struct pstore_info - backend pstore driver structure
+ *
+ * @owner:	module which is repsonsible for this backend driver
+ * @name:	name of the backend driver
+ *
+ * @buf_lock:	spinlock to serialize access to @buf
+ * @buf:	preallocated crash dump buffer
+ * @bufsize:	size of @buf available for crash dump writes
+ *
+ * @read_mutex:	serializes @open, @read, @close, and @erase callbacks
+ * @flags:	bitfield of frontends the backend can accept writes for
+ * @data:	backend-private pointer passed back during callbacks
+ *
+ * Callbacks:
+ *
+ * @open:
+ *	Notify backend that pstore is starting a full read of backend
+ *	records. Followed by one or more @read calls, and a final @close.
+ *
+ *	@psi:	in: pointer to the struct pstore_info for the backend
+ *
+ *	Returns 0 on success, and non-zero on error.
+ *
+ * @close:
+ *	Notify backend that pstore has finished a full read of backend
+ *	records. Always preceded by an @open call and one or more @read
+ *	calls.
+ *
+ *	@psi:	in: pointer to the struct pstore_info for the backend
+ *
+ *	Returns 0 on success, and non-zero on error. (Though pstore will
+ *	ignore the error.)
+ *
+ * @read:
+ *	Read next available backend record. Called after a successful
+ *	@open.
+ *
+ *	@record:
+ *		pointer to record to populate. @buf should be allocated
+ *		by the backend and filled. At least @type and @id should
+ *		be populated, since these are used when creating pstorefs
+ *		file names.
+ *
+ *	Returns record size on success, zero when no more records are
+ *	available, or negative on error.
+ *
+ * @write:
+ *	A newly generated record needs to be written to backend storage.
+ *
+ *	@record:
+ *		pointer to record metadata. When @type is PSTORE_TYPE_DMESG,
+ *		@buf will be pointing to the preallocated @psi.buf, since
+ *		memory allocation may be broken during an Oops. Regardless,
+ *		@buf must be proccesed or copied before returning. The
+ *		backend is also expected to write @id with something that
+ 8		can help identify this record to a future @erase callback.
+ *
+ *	Returns 0 on success, and non-zero on error.
+ *
+ * @write_user:
+ *	Perform a frontend write to a backend record, using a specified
+ *	buffer that is coming directly from userspace, instead of the
+ *	@record @buf.
+ *
+ *	@record:	pointer to record metadata.
+ *	@buf:		pointer to userspace contents to write to backend
+ *
+ *	Returns 0 on success, and non-zero on error.
+ *
+ * @erase:
+ *	Delete a record from backend storage.  Different backends
+ *	identify records differently, so entire original record is
+ *	passed back to assist in identification of what the backend
+ *	should remove from storage.
+ *
+ *	@record:	pointer to record metadata.
+ *
+ *	Returns 0 on success, and non-zero on error.
+ *
+ */
 struct pstore_info {
 	struct module	*owner;
 	char		*name;
-	spinlock_t	buf_lock;	/* serialize access to 'buf' */
+
+	spinlock_t	buf_lock;
 	char		*buf;
 	size_t		bufsize;
-	struct mutex	read_mutex;	/* serialize open/read/close */
+
+	struct mutex	read_mutex;
+
 	int		flags;
+	void		*data;
+
 	int		(*open)(struct pstore_info *psi);
 	int		(*close)(struct pstore_info *psi);
-	ssize_t		(*read)(u64 *id, enum pstore_type_id *type,
-			int *count, struct timespec *time, char **buf,
-			bool *compressed, ssize_t *ecc_notice_size,
-			struct pstore_info *psi);
-	int		(*write)(enum pstore_type_id type,
-			enum kmsg_dump_reason reason, u64 *id,
-			unsigned int part, int count, bool compressed,
-			size_t size, struct pstore_info *psi);
-	int		(*write_buf)(enum pstore_type_id type,
-			enum kmsg_dump_reason reason, u64 *id,
-			unsigned int part, const char *buf, bool compressed,
-			size_t size, struct pstore_info *psi);
-	int		(*write_buf_user)(enum pstore_type_id type,
-			enum kmsg_dump_reason reason, u64 *id,
-			unsigned int part, const char __user *buf,
-			bool compressed, size_t size, struct pstore_info *psi);
-	int		(*erase)(enum pstore_type_id type, u64 id,
-			int count, struct timespec time,
-			struct pstore_info *psi);
-	void		*data;
+	ssize_t		(*read)(struct pstore_record *record);
+	int		(*write)(struct pstore_record *record);
+	int		(*write_user)(struct pstore_record *record,
+				      const char __user *buf);
+	int		(*erase)(struct pstore_record *record);
 };
 
+/* Supported frontends */
 #define PSTORE_FLAGS_DMESG	(1 << 0)
-#define PSTORE_FLAGS_FRAGILE	PSTORE_FLAGS_DMESG
 #define PSTORE_FLAGS_CONSOLE	(1 << 1)
 #define PSTORE_FLAGS_FTRACE	(1 << 2)
 #define PSTORE_FLAGS_PMSG	(1 << 3)