powerpc/rtas_flash: Use simple_read_from_buffer

Simplify read file operation for /proc/powerpc/rtas/* interface
by using simple_read_from_buffer.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/kernel/rtas_flash.c b/arch/powerpc/kernel/rtas_flash.c
index 2b442e6c21e62b47409a35959e30d95b330e9f0f..bf5f5ce3a7bdd775b5b66ffc399426a2444aea71 100644 (file)
--- a/arch/powerpc/kernel/rtas_flash.c
+++ b/arch/powerpc/kernel/rtas_flash.c
@@ -256,31 +256,16 @@ static ssize_t rtas_flash_read(struct file *file, char __user *buf,
        struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);
        struct rtas_update_flash_t *uf;
        char msg[RTAS_MSG_MAXLEN];
-       int msglen;
 
-       uf = (struct rtas_update_flash_t *) dp->data;
+       uf = dp->data;
 
        if (!strcmp(dp->name, FIRMWARE_FLASH_NAME)) {
                get_flash_status_msg(uf->status, msg);
        } else {           /* FIRMWARE_UPDATE_NAME */
                sprintf(msg, "%d\n", uf->status);
        }
-       msglen = strlen(msg);
-       if (msglen > count)
-               msglen = count;
-
-       if (ppos && *ppos != 0)
-               return 0;       /* be cheap */
-
-       if (!access_ok(VERIFY_WRITE, buf, msglen))
-               return -EINVAL;
 
-       if (copy_to_user(buf, msg, msglen))
-               return -EFAULT;
-
-       if (ppos)
-               *ppos = msglen;
-       return msglen;
+       return simple_read_from_buffer(buf, count, ppos, msg, strlen(msg));
 }
 
 /* constructor for flash_block_cache */
@@ -394,26 +379,13 @@ static ssize_t manage_flash_read(struct file *file, char __user *buf,
        char msg[RTAS_MSG_MAXLEN];
        int msglen;
 
-       args_buf = (struct rtas_manage_flash_t *) dp->data;
+       args_buf = dp->data;
        if (args_buf == NULL)
                return 0;
 
        msglen = sprintf(msg, "%d\n", args_buf->status);
-       if (msglen > count)
-               msglen = count;
 
-       if (ppos && *ppos != 0)
-               return 0;       /* be cheap */
-
-       if (!access_ok(VERIFY_WRITE, buf, msglen))
-               return -EINVAL;
-
-       if (copy_to_user(buf, msg, msglen))
-               return -EFAULT;
-
-       if (ppos)
-               *ppos = msglen;
-       return msglen;
+       return simple_read_from_buffer(buf, count, ppos, msg, msglen);
 }
 
 static ssize_t manage_flash_write(struct file *file, const char __user *buf,
@@ -495,24 +467,11 @@ static ssize_t validate_flash_read(struct file *file, char __user *buf,
        char msg[RTAS_MSG_MAXLEN];
        int msglen;
 
-       args_buf = (struct rtas_validate_flash_t *) dp->data;
+       args_buf = dp->data;
 
-       if (ppos && *ppos != 0)
-               return 0;       /* be cheap */
-       
        msglen = get_validate_flash_msg(args_buf, msg);
-       if (msglen > count)
-               msglen = count;
-
-       if (!access_ok(VERIFY_WRITE, buf, msglen))
-               return -EINVAL;
-
-       if (copy_to_user(buf, msg, msglen))
-               return -EFAULT;
 
-       if (ppos)
-               *ppos = msglen;
-       return msglen;
+       return simple_read_from_buffer(buf, count, ppos, msg, msglen);
 }
 
 static ssize_t validate_flash_write(struct file *file, const char __user *buf,