Fixes for pstore for 3.11 merge window

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Merge tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux

Pull pstore update from Tony Luck:
 "Fixes for pstore for 3.11 merge window"

* tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  efivars: If pstore_register fails, free unneeded pstore buffer
  acpi: Eliminate console msg if pstore.backend excludes ERST
  pstore: Return unique error if backend registration excluded by kernel param
  pstore: Fail to unlink if a driver has not defined pstore_erase
  pstore/ram: remove the power of buffer size limitation
  pstore/ram: avoid atomic accesses for ioremapped regions
  efi, pstore: Cocci spatch "memdup.spatch"

drivers/acpi/apei/erst.c

@@ -1180,20 +1180,28 @@ static int __init erst_init(void)
 	if (!erst_erange.vaddr)
 		goto err_release_erange;
 
+	pr_info(ERST_PFX
+	"Error Record Serialization Table (ERST) support is initialized.\n");
+
 	buf = kmalloc(erst_erange.size, GFP_KERNEL);
 	spin_lock_init(&erst_info.buf_lock);
 	if (buf) {
 		erst_info.buf = buf + sizeof(struct cper_pstore_record);
 		erst_info.bufsize = erst_erange.size -
 				    sizeof(struct cper_pstore_record);
-		if (pstore_register(&erst_info)) {
+		rc = pstore_register(&erst_info);
-			pr_info(ERST_PFX "Could not register with persistent store\n");
+		if (rc) {
+			if (rc != -EPERM)
+				pr_info(ERST_PFX
+				"Could not register with persistent store\n");
+			erst_info.buf = NULL;
+			erst_info.bufsize = 0;
 			kfree(buf);
 		}
-	}
+	} else
-
+		pr_err(ERST_PFX
-	pr_info(ERST_PFX
+		"Failed to allocate %lld bytes for persistent store error log\n",
-	"Error Record Serialization Table (ERST) support is initialized.\n");
+		erst_erange.size);
 
 	return 0;
 

drivers/firmware/efi/efi-pstore.c

@@ -79,10 +79,9 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
 			   &entry->var.DataSize, entry->var.Data);
 	size = entry->var.DataSize;
 
-	*cb_data->buf = kmalloc(size, GFP_KERNEL);
+	*cb_data->buf = kmemdup(entry->var.Data, size, GFP_KERNEL);
 	if (*cb_data->buf == NULL)
 		return -ENOMEM;
-	memcpy(*cb_data->buf, entry->var.Data, size);
 	return size;
 }
 
@@ -236,7 +235,11 @@ static __init int efivars_pstore_init(void)
 	efi_pstore_info.bufsize = 1024;
 	spin_lock_init(&efi_pstore_info.buf_lock);
 
-	pstore_register(&efi_pstore_info);
+	if (pstore_register(&efi_pstore_info)) {
+		kfree(efi_pstore_info.buf);
+		efi_pstore_info.buf = NULL;
+		efi_pstore_info.bufsize = 0;
+	}
 
 	return 0;
 }

fs/pstore/inode.c

@@ -178,6 +178,8 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
 	if (p->psi->erase)
 		p->psi->erase(p->type, p->id, p->count,
 			      dentry->d_inode->i_ctime, p->psi);
+	else
+		return -EPERM;
 
 	return simple_unlink(dir, dentry);
 }

fs/pstore/platform.c

@@ -239,17 +239,15 @@ int pstore_register(struct pstore_info *psi)
 {
 	struct module *owner = psi->owner;
 
+	if (backend && strcmp(backend, psi->name))
+		return -EPERM;
+
 	spin_lock(&pstore_lock);
 	if (psinfo) {
 		spin_unlock(&pstore_lock);
 		return -EBUSY;
 	}
 
-	if (backend && strcmp(backend, psi->name)) {
-		spin_unlock(&pstore_lock);
-		return -EINVAL;
-	}
-
 	if (!psi->write)
 		psi->write = pstore_write_compat;
 	psinfo = psi;
@@ -274,6 +272,9 @@ int pstore_register(struct pstore_info *psi)
 		add_timer(&pstore_timer);
 	}
 
+	pr_info("pstore: Registered %s as persistent store backend\n",
+		psi->name);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(pstore_register);

fs/pstore/ram.c

@@ -399,8 +399,6 @@ static int ramoops_probe(struct platform_device *pdev)
 		goto fail_out;
 	}
 
-	if (!is_power_of_2(pdata->mem_size))
-		pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
 	if (!is_power_of_2(pdata->record_size))
 		pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 	if (!is_power_of_2(pdata->console_size))

fs/pstore/ram_core.c

@@ -46,7 +46,7 @@ static inline size_t buffer_start(struct persistent_ram_zone *prz)
 }
 
 /* increase and wrap the start pointer, returning the old value */
-static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
+static size_t buffer_start_add_atomic(struct persistent_ram_zone *prz, size_t a)
 {
 	int old;
 	int new;
@@ -62,7 +62,7 @@ static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
 }
 
 /* increase the size counter until it hits the max size */
-static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
+static void buffer_size_add_atomic(struct persistent_ram_zone *prz, size_t a)
 {
 	size_t old;
 	size_t new;
@@ -78,6 +78,53 @@ static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
 	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
 }
 
+static DEFINE_RAW_SPINLOCK(buffer_lock);
+
+/* increase and wrap the start pointer, returning the old value */
+static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a)
+{
+	int old;
+	int new;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&buffer_lock, flags);
+
+	old = atomic_read(&prz->buffer->start);
+	new = old + a;
+	while (unlikely(new > prz->buffer_size))
+		new -= prz->buffer_size;
+	atomic_set(&prz->buffer->start, new);
+
+	raw_spin_unlock_irqrestore(&buffer_lock, flags);
+
+	return old;
+}
+
+/* increase the size counter until it hits the max size */
+static void buffer_size_add_locked(struct persistent_ram_zone *prz, size_t a)
+{
+	size_t old;
+	size_t new;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&buffer_lock, flags);
+
+	old = atomic_read(&prz->buffer->size);
+	if (old == prz->buffer_size)
+		goto exit;
+
+	new = old + a;
+	if (new > prz->buffer_size)
+		new = prz->buffer_size;
+	atomic_set(&prz->buffer->size, new);
+
+exit:
+	raw_spin_unlock_irqrestore(&buffer_lock, flags);
+}
+
+static size_t (*buffer_start_add)(struct persistent_ram_zone *, size_t) = buffer_start_add_atomic;
+static void (*buffer_size_add)(struct persistent_ram_zone *, size_t) = buffer_size_add_atomic;
+
 static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
 	uint8_t *data, size_t len, uint8_t *ecc)
 {
@@ -372,6 +419,9 @@ static void *persistent_ram_iomap(phys_addr_t start, size_t size)
 		return NULL;
 	}
 
+	buffer_start_add = buffer_start_add_locked;
+	buffer_size_add = buffer_size_add_locked;
+
 	return ioremap(start, size);
 }