3 files changed, 39 insertions, 8 deletions

diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index 503086f7f7c1..0d19d191ae70 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -141,7 +141,6 @@ config PSTORE_RAM
 	tristate "Log panic/oops to a RAM buffer"
 	depends on PSTORE
 	depends on HAS_IOMEM
-	depends on HAVE_MEMBLOCK
 	select REED_SOLOMON
 	select REED_SOLOMON_ENC8
 	select REED_SOLOMON_DEC8
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 8646fe6e916f..e02a9039b5ea 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -905,8 +905,22 @@ static struct platform_driver ramoops_driver = {
 	},
 };
 
-static void ramoops_register_dummy(void)
+static inline void ramoops_unregister_dummy(void)
 {
+	platform_device_unregister(dummy);
+	dummy = NULL;
+
+	kfree(dummy_data);
+	dummy_data = NULL;
+}
+
+static void __init ramoops_register_dummy(void)
+{
+	/*
+	 * Prepare a dummy platform data structure to carry the module
+	 * parameters. If mem_size isn't set, then there are no module
+	 * parameters, and we can skip this.
+	 */
 	if (!mem_size)
 		return;
 
@@ -939,21 +953,28 @@ static void ramoops_register_dummy(void)
 	if (IS_ERR(dummy)) {
 		pr_info("could not create platform device: %ld\n",
 			PTR_ERR(dummy));
+		dummy = NULL;
+		ramoops_unregister_dummy();
 	}
 }
 
 static int __init ramoops_init(void)
 {
+	int ret;
+
 	ramoops_register_dummy();
-	return platform_driver_register(&ramoops_driver);
+	ret = platform_driver_register(&ramoops_driver);
+	if (ret != 0)
+		ramoops_unregister_dummy();
+
+	return ret;
 }
 postcore_initcall(ramoops_init);
 
 static void __exit ramoops_exit(void)
 {
 	platform_driver_unregister(&ramoops_driver);
-	platform_device_unregister(dummy);
-	kfree(dummy_data);
+	ramoops_unregister_dummy();
 }
 module_exit(ramoops_exit);
 
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index f200dcefb3b4..12e21f789194 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -429,7 +429,12 @@ static void *persistent_ram_vmap(phys_addr_t start, size_t size,
 	vaddr = vmap(pages, page_count, VM_MAP, prot);
 	kfree(pages);
 
-	return vaddr;
+	/*
+	 * Since vmap() uses page granularity, we must add the offset
+	 * into the page here, to get the byte granularity address
+	 * into the mapping to represent the actual "start" location.
+	 */
+	return vaddr + offset_in_page(start);
 }
 
 static void *persistent_ram_iomap(phys_addr_t start, size_t size,
@@ -448,6 +453,11 @@ static void *persistent_ram_iomap(phys_addr_t start, size_t size,
 	else
 		va = ioremap_wc(start, size);
 
+	/*
+	 * Since request_mem_region() and ioremap() are byte-granularity
+	 * there is no need handle anything special like we do when the
+	 * vmap() case in persistent_ram_vmap() above.
+	 */
 	return va;
 }
 
@@ -469,7 +479,7 @@ static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
 		return -ENOMEM;
 	}
 
-	prz->buffer = prz->vaddr + offset_in_page(start);
+	prz->buffer = prz->vaddr;
 	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
 
 	return 0;
@@ -516,7 +526,8 @@ void persistent_ram_free(struct persistent_ram_zone *prz)
 
 	if (prz->vaddr) {
 		if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
-			vunmap(prz->vaddr);
+			/* We must vunmap() at page-granularity. */
+			vunmap(prz->vaddr - offset_in_page(prz->paddr));
 		} else {
 			iounmap(prz->vaddr);
 			release_mem_region(prz->paddr, prz->size);