1 files changed, 35 insertions, 19 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 1f528fad3516..8fc04b4f311f 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -47,10 +47,7 @@ static inline unsigned long size_inside_page(unsigned long start,
 #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
 static inline int valid_phys_addr_range(unsigned long addr, size_t count)
 {
-        if (addr + count > __pa(high_memory))
-                return 0;
-
-        return 1;
+        return addr + count <= __pa(high_memory);
 }
 
 static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
@@ -805,32 +802,46 @@ static const struct file_operations full_fops = {
 static const struct file_operations oldmem_fops = {
         .read   = read_oldmem,
         .open   = open_oldmem,
+        .llseek = default_llseek,
 };
 #endif
 
-static ssize_t kmsg_write(struct file *file, const char __user *buf,
-                          size_t count, loff_t *ppos)
+static ssize_t kmsg_writev(struct kiocb *iocb, const struct iovec *iv,
+                           unsigned long count, loff_t pos)
 {
-        char *tmp;
-        ssize_t ret;
+        char *line, *p;
+        int i;
+        ssize_t ret = -EFAULT;
+        size_t len = iov_length(iv, count);
 
-        tmp = kmalloc(count + 1, GFP_KERNEL);
-        if (tmp == NULL)
+        line = kmalloc(len + 1, GFP_KERNEL);
+        if (line == NULL)
                 return -ENOMEM;
-        ret = -EFAULT;
-        if (!copy_from_user(tmp, buf, count)) {
-                tmp[count] = 0;
-                ret = printk("%s", tmp);
-                if (ret > count)
-                        /* printk can add a prefix */
-                        ret = count;
+
+        /*
+         * copy all vectors into a single string, to ensure we do
+         * not interleave our log line with other printk calls
+         */
+        p = line;
+        for (i = 0; i < count; i++) {
+                if (copy_from_user(p, iv[i].iov_base, iv[i].iov_len))
+                        goto out;
+                p += iv[i].iov_len;
         }
-        kfree(tmp);
+        p[0] = '\0';
+
+        ret = printk("%s", line);
+        /* printk can add a prefix */
+        if (ret > len)
+                ret = len;
+out:
+        kfree(line);
         return ret;
 }
 
 static const struct file_operations kmsg_fops = {
-        .write = kmsg_write,
+        .aio_write = kmsg_writev,
+        .llseek = noop_llseek,
 };
 
 static const struct memdev {
@@ -874,6 +885,10 @@ static int memory_open(struct inode *inode, struct file *filp)
         if (dev->dev_info)
                 filp->f_mapping->backing_dev_info = dev->dev_info;
 
+        /* Is /dev/mem or /dev/kmem ? */
+        if (dev->dev_info == &directly_mappable_cdev_bdi)
+                filp->f_mode |= FMODE_UNSIGNED_OFFSET;
+
         if (dev->fops->open)
                 return dev->fops->open(inode, filp);
 
@@ -882,6 +897,7 @@ static int memory_open(struct inode *inode, struct file *filp)
 
 static const struct file_operations memory_fops = {
         .open = memory_open,
+        .llseek = noop_llseek,
 };
 
 static char *mem_devnode(struct device *dev, mode_t *mode)