pstore: make pstore write function return normal success/fail value

Currently pstore write interface employs record id as return
value, but it is not enough because it can't tell caller if
the write operation is successful. Pass the record id back via
an argument pointer and return zero for success, non-zero for
failure.

Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

drivers/acpi/apei/erst.c

@@ -933,7 +933,7 @@ 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,
 			   struct timespec *time, struct pstore_info *psi);
-static u64 erst_writer(enum pstore_type_id type, unsigned int part,
+static int erst_writer(enum pstore_type_id type, u64 *id, unsigned int part,
 		       size_t size, struct pstore_info *psi);
 static int erst_clearer(enum pstore_type_id type, u64 id,
 			struct pstore_info *psi);
@@ -1040,11 +1040,12 @@ out:
 	return (rc < 0) ? rc : (len - sizeof(*rcd));
 }
 
-static u64 erst_writer(enum pstore_type_id type, unsigned int part,
+static int erst_writer(enum pstore_type_id type, u64 *id, unsigned int part,
 		       size_t size, struct pstore_info *psi)
 {
 	struct cper_pstore_record *rcd = (struct cper_pstore_record *)
 					(erst_info.buf - sizeof(*rcd));
+	int ret;
 
 	memset(rcd, 0, sizeof(*rcd));
 	memcpy(rcd->hdr.signature, CPER_SIG_RECORD, CPER_SIG_SIZE);
@@ -1079,9 +1080,10 @@ static u64 erst_writer(enum pstore_type_id type, unsigned int part,
 	}
 	rcd->sec_hdr.section_severity = CPER_SEV_FATAL;
 
-	erst_write(&rcd->hdr);
+	ret = erst_write(&rcd->hdr);
+	*id = rcd->hdr.record_id;
 
-	return rcd->hdr.record_id;
+	return ret;
 }
 
 static int erst_clearer(enum pstore_type_id type, u64 id,

drivers/firmware/efivars.c

@@ -490,8 +490,8 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 	return 0;
 }
 
-static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
-			    size_t size, struct pstore_info *psi)
+static int efi_pstore_write(enum pstore_type_id type, u64 *id,
+		unsigned int part, size_t size, struct pstore_info *psi)
 {
 	char name[DUMP_NAME_LEN];
 	char stub_name[DUMP_NAME_LEN];
@@ -499,7 +499,7 @@ static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
 	efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 	struct efivars *efivars = psi->data;
 	struct efivar_entry *entry, *found = NULL;
-	int i;
+	int i, ret = 0;
 
 	sprintf(stub_name, "dump-type%u-%u-", type, part);
 	sprintf(name, "%s%lu", stub_name, get_seconds());
@@ -548,18 +548,19 @@ static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
 		efivar_unregister(found);
 
 	if (size)
-		efivar_create_sysfs_entry(efivars,
+		ret = efivar_create_sysfs_entry(efivars,
 					  utf16_strsize(efi_name,
 							DUMP_NAME_LEN * 2),
 					  efi_name, &vendor);
 
-	return part;
+	*id = part;
+	return ret;
 };
 
 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
 			    struct pstore_info *psi)
 {
-	efi_pstore_write(type, id, 0, psi);
+	efi_pstore_write(type, &id, (unsigned int)id, 0, psi);
 
 	return 0;
 }
@@ -580,8 +581,8 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 	return -1;
 }
 
-static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
-			    size_t size, struct pstore_info *psi)
+static int efi_pstore_write(enum pstore_type_id type, u64 *id,
+		unsigned int part, size_t size, struct pstore_info *psi)
 {
 	return 0;
 }

fs/pstore/platform.c

@@ -87,7 +87,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 	unsigned long	size, total = 0;
 	char		*dst, *why;
 	u64		id;
-	int		hsize;
+	int		hsize, ret;
 	unsigned int	part = 1;
 	unsigned long	flags = 0;
 	int		is_locked = 0;
@@ -122,9 +122,9 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 		memcpy(dst, s1 + s1_start, l1_cpy);
 		memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
 
-		id = psinfo->write(PSTORE_TYPE_DMESG, part,
+		ret = psinfo->write(PSTORE_TYPE_DMESG, &id, part,
 				   hsize + l1_cpy + l2_cpy, psinfo);
-		if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
+		if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
 			pstore_new_entry = 1;
 		l1 -= l1_cpy;
 		l2 -= l2_cpy;
@@ -247,6 +247,7 @@ static void pstore_timefunc(unsigned long dummy)
 int pstore_write(enum pstore_type_id type, char *buf, size_t size)
 {
 	u64		id;
+	int		ret;
 	unsigned long	flags;
 
 	if (!psinfo)
@@ -257,8 +258,8 @@ int pstore_write(enum pstore_type_id type, char *buf, size_t size)
 
 	spin_lock_irqsave(&psinfo->buf_lock, flags);
 	memcpy(psinfo->buf, buf, size);
-	id = psinfo->write(type, 0, size, psinfo);
-	if (pstore_is_mounted())
+	ret = psinfo->write(type, &id, 0, size, psinfo);
+	if (ret == 0 && pstore_is_mounted())
 		pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
 			      size, CURRENT_TIME, psinfo);
 	spin_unlock_irqrestore(&psinfo->buf_lock, flags);

include/linux/pstore.h

@@ -39,8 +39,8 @@ struct pstore_info {
 	int		(*close)(struct pstore_info *psi);
 	ssize_t		(*read)(u64 *id, enum pstore_type_id *type,
 			struct timespec *time, struct pstore_info *psi);
-	u64		(*write)(enum pstore_type_id type, unsigned int part,
-			size_t size, struct pstore_info *psi);
+	int		(*write)(enum pstore_type_id type, u64 *id,
+			unsigned int part, size_t size, struct pstore_info *psi);
 	int		(*erase)(enum pstore_type_id type, u64 id,
 			struct pstore_info *psi);
 	void		*data;