vmw_balloon: simplify vmballoon_send_get_target()

As we want to leave as little as possible on the global balloon
structure, to avoid possible future races, we want to get rid sysinfo.
We can actually get the total_ram directly, and simplify the logic of
vmballoon_send_get_target() a little.

While we are doing that, let's return int and avoid mistakes due to
bool/int conversions.

Reviewed-by: Xavier Deguillard <xdeguillard@vmware.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 0d9f223d463e25e9341adb48ae1914b25421ab8d..3c80a21e0f913d5b090608192a31f631b02a2ae5 100644 (file)
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -223,8 +223,6 @@ struct vmballoon {
        struct dentry *dbg_entry;
 #endif
 
-       struct sysinfo sysinfo;
-
        struct delayed_work dwork;
 
        struct vmci_handle vmci_doorbell;
@@ -353,34 +351,29 @@ static u16 vmballoon_page_size(bool is_2m_page)
        return 1;
 }
 
-/*
- * Retrieve desired balloon size from the host.
+/**
+ * vmballoon_send_get_target() - Retrieve desired balloon size from the host.
+ *
+ * @b: pointer to the balloon.
+ *
+ * Return: zero on success, EINVAL if limit does not fit in 32-bit, as required
+ * by the host-guest protocol and EIO if an error occurred in communicating with
+ * the host.
  */
-static bool vmballoon_send_get_target(struct vmballoon *b)
+static int vmballoon_send_get_target(struct vmballoon *b)
 {
        unsigned long status;
        unsigned long limit;
-       u32 limit32;
 
-       /*
-        * si_meminfo() is cheap. Moreover, we want to provide dynamic
-        * max balloon size later. So let us call si_meminfo() every
-        * iteration.
-        */
-       si_meminfo(&b->sysinfo);
-       limit = b->sysinfo.totalram;
+       limit = totalram_pages;
 
        /* Ensure limit fits in 32-bits */
-       limit32 = (u32)limit;
-       if (limit != limit32)
-               return false;
+       if (limit != (u32)limit)
+               return -EINVAL;
 
        status = vmballoon_cmd(b, VMW_BALLOON_CMD_GET_TARGET, limit, 0);
 
-       if (status == VMW_BALLOON_SUCCESS)
-               return true;
-
-       return false;
+       return status == VMW_BALLOON_SUCCESS ? 0 : -EIO;
 }
 
 static struct page *vmballoon_alloc_page(bool is_2m_page)
@@ -962,7 +955,7 @@ static void vmballoon_work(struct work_struct *work)
        if (b->reset_required)
                vmballoon_reset(b);
 
-       if (vmballoon_send_get_target(b))
+       if (!vmballoon_send_get_target(b))
                change = vmballoon_change(b);
 
        if (change != 0) {