Merge 4.4.172 into android-4.4

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / fs / pstore / ram_core.c

diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 679d75a..11e558e 100644 (file)
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -17,15 +17,16 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/errno.h>
-#include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/io.h>
+#include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/memblock.h>
+#include <linux/pstore_ram.h>
 #include <linux/rslib.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 #include <linux/vmalloc.h>
-#include <linux/pstore_ram.h>
 #include <asm/page.h>
 
 struct persistent_ram_buffer {
@@ -269,6 +270,16 @@ static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
        persistent_ram_update_ecc(prz, start, count);
 }
 
+static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz,
+       const void __user *s, unsigned int start, unsigned int count)
+{
+       struct persistent_ram_buffer *buffer = prz->buffer;
+       int ret = unlikely(__copy_from_user(buffer->data + start, s, count)) ?
+               -EFAULT : 0;
+       persistent_ram_update_ecc(prz, start, count);
+       return ret;
+}
+
 void persistent_ram_save_old(struct persistent_ram_zone *prz)
 {
        struct persistent_ram_buffer *buffer = prz->buffer;
@@ -322,6 +333,38 @@ int notrace persistent_ram_write(struct persistent_ram_zone *prz,
        return count;
 }
 
+int notrace persistent_ram_write_user(struct persistent_ram_zone *prz,
+       const void __user *s, unsigned int count)
+{
+       int rem, ret = 0, c = count;
+       size_t start;
+
+       if (unlikely(!access_ok(VERIFY_READ, s, count)))
+               return -EFAULT;
+       if (unlikely(c > prz->buffer_size)) {
+               s += c - prz->buffer_size;
+               c = prz->buffer_size;
+       }
+
+       buffer_size_add(prz, c);
+
+       start = buffer_start_add(prz, c);
+
+       rem = prz->buffer_size - start;
+       if (unlikely(rem < c)) {
+               ret = persistent_ram_update_user(prz, s, start, rem);
+               s += rem;
+               c -= rem;
+               start = 0;
+       }
+       if (likely(!ret))
+               ret = persistent_ram_update_user(prz, s, start, c);
+
+       persistent_ram_update_header_ecc(prz);
+
+       return unlikely(ret) ? ret : count;
+}
+
 size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
 {
        return prz->old_log_size;