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>

1 files changed, 10 insertions, 3 deletions

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index e11b57e1939c..1bed1ba2fe5e 100644
--- 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;
 }