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>

1 files changed, 6 insertions, 47 deletions

diff --git a/arch/powerpc/kernel/rtas_flash.c b/arch/powerpc/kernel/rtas_flash.c
index 2b442e6c21e6..bf5f5ce3a7bd 100644
--- 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,