pstore: Extend API for more flexibility in new backends

Some pstore implementations may not have a static context, so extend the
API to pass the pstore_info struct to all calls and allow for a context
pointer.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

drivers/acpi/apei/erst.c

@@ -932,8 +932,10 @@ 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,
-		       struct timespec *time);
-static u64 erst_writer(enum pstore_type_id type, size_t size);
+			   struct timespec *time, struct pstore_info *psi);
+static u64 erst_writer(enum pstore_type_id type, size_t size,
+		       struct pstore_info *psi);
+static int erst_clearer(u64 id, struct pstore_info *psi);
 
 static struct pstore_info erst_info = {
 	.owner		= THIS_MODULE,
@@ -942,7 +944,7 @@ static struct pstore_info erst_info = {
 	.close		= erst_close_pstore,
 	.read		= erst_reader,
 	.write		= erst_writer,
-	.erase		= erst_clear
+	.erase		= erst_clearer
 };
 
 #define CPER_CREATOR_PSTORE						\
@@ -983,7 +985,7 @@ 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 timespec *time, struct pstore_info *psi)
 {
 	int rc;
 	ssize_t len = 0;
@@ -1037,7 +1039,8 @@ static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
 	return (rc < 0) ? rc : (len - sizeof(*rcd));
 }
 
-static u64 erst_writer(enum pstore_type_id type, size_t size)
+static u64 erst_writer(enum pstore_type_id type, size_t size,
+		       struct pstore_info *psi)
 {
 	struct cper_pstore_record *rcd = (struct cper_pstore_record *)
 					(erst_info.buf - sizeof(*rcd));
@@ -1080,6 +1083,11 @@ static u64 erst_writer(enum pstore_type_id type, size_t size)
 	return rcd->hdr.record_id;
 }
 
+static int erst_clearer(u64 id, struct pstore_info *psi)
+{
+	return erst_clear(id);
+}
+
 static int __init erst_init(void)
 {
 	int rc = 0;

fs/pstore/inode.c

@@ -40,7 +40,7 @@
 
 struct pstore_private {
 	u64	id;
-	int	(*erase)(u64);
+	struct pstore_info *psi;
 	ssize_t	size;
 	char	data[];
 };
@@ -73,7 +73,7 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct pstore_private *p = dentry->d_inode->i_private;
 
-	p->erase(p->id);
+	p->psi->erase(p->id, p->psi);
 
 	return simple_unlink(dir, dentry);
 }
@@ -175,8 +175,8 @@ int pstore_is_mounted(void)
  * 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,
-			      char *data, size_t size,
-			      struct timespec time, int (*erase)(u64))
+		  char *data, size_t size, struct timespec time,
+		  struct pstore_info *psi)
 {
 	struct dentry		*root = pstore_sb->s_root;
 	struct dentry		*dentry;
@@ -193,7 +193,7 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
 	if (!private)
 		goto fail_alloc;
 	private->id = id;
-	private->erase = erase;
+	private->psi = psi;
 
 	switch (type) {
 	case PSTORE_TYPE_DMESG:

fs/pstore/internal.h

@@ -2,5 +2,5 @@ extern void	pstore_set_kmsg_bytes(int);
 extern void	pstore_get_records(void);
 extern int	pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
 			      char *data, size_t size,
-			      struct timespec time, int (*erase)(u64));
+			      struct timespec time, struct pstore_info *psi);
 extern int	pstore_is_mounted(void);

fs/pstore/platform.c

@@ -94,11 +94,12 @@ 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, hsize + l1_cpy + l2_cpy);
+		id = psinfo->write(PSTORE_TYPE_DMESG, hsize + l1_cpy + l2_cpy,
+				   psinfo);
 		if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
 			pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id,
 				      psinfo->buf, hsize + l1_cpy + l2_cpy,
-				      CURRENT_TIME, psinfo->erase);
+				      CURRENT_TIME, psinfo);
 		l1 -= l1_cpy;
 		l2 -= l2_cpy;
 		total += l1_cpy + l2_cpy;
@@ -166,9 +167,9 @@ void pstore_get_records(void)
 	if (rc)
 		goto out;
 
-	while ((size = psi->read(&id, &type, &time)) > 0) {
+	while ((size = psi->read(&id, &type, &time, psi)) > 0) {
 		if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
-				  time, psi->erase))
+				  time, psi))
 			failed++;
 	}
 	psi->close(psi);
@@ -196,10 +197,10 @@ int pstore_write(enum pstore_type_id type, char *buf, size_t size)
 
 	mutex_lock(&psinfo->buf_mutex);
 	memcpy(psinfo->buf, buf, size);
-	id = psinfo->write(type, size);
+	id = psinfo->write(type, size, psinfo);
 	if (pstore_is_mounted())
 		pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
-			      size, CURRENT_TIME, psinfo->erase);
+			      size, CURRENT_TIME, psinfo);
 	mutex_unlock(&psinfo->buf_mutex);
 
 	return 0;

include/linux/pstore.h

@@ -38,9 +38,11 @@ struct pstore_info {
 	int		(*open)(struct pstore_info *psi);
 	int		(*close)(struct pstore_info *psi);
 	ssize_t		(*read)(u64 *id, enum pstore_type_id *type,
-			struct timespec *time);
-	u64		(*write)(enum pstore_type_id type, size_t size);
-	int		(*erase)(u64 id);
+			struct timespec *time, struct pstore_info *psi);
+	u64		(*write)(enum pstore_type_id type, size_t size,
+			struct pstore_info *psi);
+	int		(*erase)(u64 id, struct pstore_info *psi);
+	void		*data;
 };
 
 #ifdef CONFIG_PSTORE