Merge tag 'pstore-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees...

[linux-2.6-block.git] / fs / pstore / ram_core.c

diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index f200dcefb3b46b34f19d6d2b70b739be65631a32..12e21f789194b9ae1842b16329079dd176297080 100644 (file)
--- 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);