Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  pstore: pass allocated memory region back to caller

drivers/acpi/apei/erst.c

@@ -932,7 +932,8 @@ 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, struct pstore_info *psi);
+			   struct timespec *time, char **buf,
+			   struct pstore_info *psi);
 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,
@@ -986,17 +987,23 @@ 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)
+			   struct timespec *time, char **buf,
+			   struct pstore_info *psi)
 {
 	int rc;
 	ssize_t len = 0;
 	u64 record_id;
-	struct cper_pstore_record *rcd = (struct cper_pstore_record *)
-					(erst_info.buf - sizeof(*rcd));
+	struct cper_pstore_record *rcd;
+	size_t rcd_len = sizeof(*rcd) + erst_info.bufsize;
 
 	if (erst_disable)
 		return -ENODEV;
 
+	rcd = kmalloc(rcd_len, GFP_KERNEL);
+	if (!rcd) {
+		rc = -ENOMEM;
+		goto out;
+	}
 skip:
 	rc = erst_get_record_id_next(&reader_pos, &record_id);
 	if (rc)
@@ -1004,22 +1011,27 @@ static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
 
 	/* no more record */
 	if (record_id == APEI_ERST_INVALID_RECORD_ID) {
-		rc = -1;
+		rc = -EINVAL;
 		goto out;
 	}
 
-	len = erst_read(record_id, &rcd->hdr, sizeof(*rcd) +
-			erst_info.bufsize);
+	len = erst_read(record_id, &rcd->hdr, rcd_len);
 	/* The record may be cleared by others, try read next record */
 	if (len == -ENOENT)
 		goto skip;
-	else if (len < 0) {
-		rc = -1;
+	else if (len < sizeof(*rcd)) {
+		rc = -EIO;
 		goto out;
 	}
 	if (uuid_le_cmp(rcd->hdr.creator_id, CPER_CREATOR_PSTORE) != 0)
 		goto skip;
 
+	*buf = kmalloc(len, GFP_KERNEL);
+	if (*buf == NULL) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	memcpy(*buf, rcd->data, len - sizeof(*rcd));
 	*id = record_id;
 	if (uuid_le_cmp(rcd->sec_hdr.section_type,
 			CPER_SECTION_TYPE_DMESG) == 0)
@@ -1037,6 +1049,7 @@ static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
 	time->tv_nsec = 0;
 
 out:
+	kfree(rcd);
 	return (rc < 0) ? rc : (len - sizeof(*rcd));
 }
 

drivers/firmware/efivars.c

@@ -457,7 +457,8 @@ static int efi_pstore_close(struct pstore_info *psi)
 }
 
 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
-			       struct timespec *timespec, struct pstore_info *psi)
+			       struct timespec *timespec,
+			       char **buf, struct pstore_info *psi)
 {
 	efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 	struct efivars *efivars = psi->data;
@@ -478,7 +479,11 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
 				timespec->tv_nsec = 0;
 				get_var_data_locked(efivars, &efivars->walk_entry->var);
 				size = efivars->walk_entry->var.DataSize;
-				memcpy(psi->buf, efivars->walk_entry->var.Data, size);
+				*buf = kmalloc(size, GFP_KERNEL);
+				if (*buf == NULL)
+					return -ENOMEM;
+				memcpy(*buf, efivars->walk_entry->var.Data,
+				       size);
 				efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
 					           struct efivar_entry, list);
 				return size;

fs/pstore/platform.c

@@ -167,6 +167,7 @@ int pstore_register(struct pstore_info *psi)
 	}
 
 	psinfo = psi;
+	mutex_init(&psinfo->read_mutex);
 	spin_unlock(&pstore_lock);
 
 	if (owner && !try_module_get(owner)) {
@@ -195,30 +196,32 @@ EXPORT_SYMBOL_GPL(pstore_register);
 void pstore_get_records(int quiet)
 {
 	struct pstore_info *psi = psinfo;
+	char			*buf = NULL;
 	ssize_t			size;
 	u64			id;
 	enum pstore_type_id	type;
 	struct timespec		time;
 	int			failed = 0, rc;
-	unsigned long		flags;
 
 	if (!psi)
 		return;
 
-	spin_lock_irqsave(&psinfo->buf_lock, flags);
+	mutex_lock(&psi->read_mutex);
 	rc = psi->open(psi);
 	if (rc)
 		goto out;
 
-	while ((size = psi->read(&id, &type, &time, psi)) > 0) {
-		rc = pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
+	while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) {
+		rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size,
 				  time, psi);
+		kfree(buf);
+		buf = NULL;
 		if (rc && (rc != -EEXIST || !quiet))
 			failed++;
 	}
 	psi->close(psi);
 out:
-	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
+	mutex_unlock(&psi->read_mutex);
 
 	if (failed)
 		printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",

include/linux/pstore.h

@@ -35,10 +35,12 @@ struct pstore_info {
 	spinlock_t	buf_lock;	/* serialize access to 'buf' */
 	char		*buf;
 	size_t		bufsize;
+	struct mutex	read_mutex;	/* serialize open/read/close */
 	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, struct pstore_info *psi);
+			struct timespec *time, char **buf,
+			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,