NTB: correct stack usage warning in debugfs_read

Correct gcc warning of using too much stack debugfs_read.  This is done
by kmallocing the buffer instead of using the char array on stack.
Also, shrinking the buffer to something closer to what is currently
being used.

Signed-off-by: Jon Mason <jon.mason@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index e11b57e1939cbc6087a9fea54cea357372bde090..1bed1ba2fe5e53a8cb30939317acb3100d603a89 100644 (file)
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -368,10 +368,14 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
                            loff_t *offp)
 {
        struct ntb_transport_qp *qp;
-       char buf[1024];
+       char *buf;
        ssize_t ret, out_offset, out_count;
 
-       out_count = 1024;
+       out_count = 600;
+
+       buf = kmalloc(out_count, GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
 
        qp = filp->private_data;
        out_offset = 0;
@@ -410,10 +414,13 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
                               "tx_mw_end - \t%p\n", qp->tx_mw_end);
 
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
-                              "QP Link %s\n", (qp->qp_link == NTB_LINK_UP) ?
+                              "\nQP Link %s\n", (qp->qp_link == NTB_LINK_UP) ?
                               "Up" : "Down");
+       if (out_offset > out_count)
+               out_offset = out_count;
 
        ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
+       kfree(buf);
        return ret;
 }