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path: root/drivers/s390/char/vmcp.c
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Diffstat (limited to 'drivers/s390/char/vmcp.c')
-rw-r--r--drivers/s390/char/vmcp.c41
1 files changed, 17 insertions, 24 deletions
diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c
index 2f419b0ea628..09e7d9bf438b 100644
--- a/drivers/s390/char/vmcp.c
+++ b/drivers/s390/char/vmcp.c
@@ -16,6 +16,7 @@
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
+#include <linux/smp_lock.h>
#include <asm/cpcmd.h>
#include <asm/debug.h>
#include <asm/uaccess.h>
@@ -39,11 +40,14 @@ static int vmcp_open(struct inode *inode, struct file *file)
session = kmalloc(sizeof(*session), GFP_KERNEL);
if (!session)
return -ENOMEM;
+
+ lock_kernel();
session->bufsize = PAGE_SIZE;
session->response = NULL;
session->resp_size = 0;
mutex_init(&session->mutex);
file->private_data = session;
+ unlock_kernel();
return nonseekable_open(inode, file);
}
@@ -61,30 +65,24 @@ static int vmcp_release(struct inode *inode, struct file *file)
static ssize_t
vmcp_read(struct file *file, char __user *buff, size_t count, loff_t *ppos)
{
- size_t tocopy;
+ ssize_t ret;
+ size_t size;
struct vmcp_session *session;
- session = (struct vmcp_session *)file->private_data;
+ session = file->private_data;
if (mutex_lock_interruptible(&session->mutex))
return -ERESTARTSYS;
if (!session->response) {
mutex_unlock(&session->mutex);
return 0;
}
- if (*ppos > session->resp_size) {
- mutex_unlock(&session->mutex);
- return 0;
- }
- tocopy = min(session->resp_size - (size_t) (*ppos), count);
- tocopy = min(tocopy, session->bufsize - (size_t) (*ppos));
+ size = min_t(size_t, session->resp_size, session->bufsize);
+ ret = simple_read_from_buffer(buff, count, ppos,
+ session->response, size);
- if (copy_to_user(buff, session->response + (*ppos), tocopy)) {
- mutex_unlock(&session->mutex);
- return -EFAULT;
- }
mutex_unlock(&session->mutex);
- *ppos += tocopy;
- return tocopy;
+
+ return ret;
}
static ssize_t
@@ -198,27 +196,23 @@ static int __init vmcp_init(void)
PRINT_WARN("z/VM CP interface is only available under z/VM\n");
return -ENODEV;
}
+
vmcp_debug = debug_register("vmcp", 1, 1, 240);
- if (!vmcp_debug) {
- PRINT_ERR("z/VM CP interface not loaded. Could not register "
- "debug feature\n");
+ if (!vmcp_debug)
return -ENOMEM;
- }
+
ret = debug_register_view(vmcp_debug, &debug_hex_ascii_view);
if (ret) {
- PRINT_ERR("z/VM CP interface not loaded. Could not register "
- "debug feature view. Error code: %d\n", ret);
debug_unregister(vmcp_debug);
return ret;
}
+
ret = misc_register(&vmcp_dev);
if (ret) {
- PRINT_ERR("z/VM CP interface not loaded. Could not register "
- "misc device. Error code: %d\n", ret);
debug_unregister(vmcp_debug);
return ret;
}
- PRINT_INFO("z/VM CP interface loaded\n");
+
return 0;
}
@@ -226,7 +220,6 @@ static void __exit vmcp_exit(void)
{
misc_deregister(&vmcp_dev);
debug_unregister(vmcp_debug);
- PRINT_INFO("z/VM CP interface unloaded.\n");
}
module_init(vmcp_init);