diag: Set in_busy only after initialization of read buffers

Currently, there is a possibility that read buffers are
not initialized but diag ends up marking buffers busy and
stops reading from peripheral, which leads to port loss.
Also reset the in_busy variable for the buffer that reads
the data from smd channel when diag smd state is closed.

CRs-Fixed: 1093989
Change-Id: I1990d0ded5a212c9185c149ac297a3630d64bc59
Signed-off-by: Mohit Aggarwal <maggarwa@codeaurora.org>
diff --git a/drivers/char/diag/diagfwd_peripheral.c b/drivers/char/diag/diagfwd_peripheral.c
index 4f7c1e0..6685be3 100644
--- a/drivers/char/diag/diagfwd_peripheral.c
+++ b/drivers/char/diag/diagfwd_peripheral.c
@@ -983,8 +983,6 @@
 	}
 
 	if (fwd_info->buf_1 && !atomic_read(&fwd_info->buf_1->in_busy)) {
-		temp_buf = fwd_info->buf_1;
-		atomic_set(&temp_buf->in_busy, 1);
 		if (driver->feature[fwd_info->peripheral].encode_hdlc &&
 		    (fwd_info->type == TYPE_DATA ||
 		     fwd_info->type == TYPE_CMD)) {
@@ -994,9 +992,11 @@
 			read_buf = fwd_info->buf_1->data;
 			read_len = fwd_info->buf_1->len;
 		}
+		if (read_buf) {
+			temp_buf = fwd_info->buf_1;
+			atomic_set(&temp_buf->in_busy, 1);
+		}
 	} else if (fwd_info->buf_2 && !atomic_read(&fwd_info->buf_2->in_busy)) {
-		temp_buf = fwd_info->buf_2;
-		atomic_set(&temp_buf->in_busy, 1);
 		if (driver->feature[fwd_info->peripheral].encode_hdlc &&
 		    (fwd_info->type == TYPE_DATA ||
 		     fwd_info->type == TYPE_CMD)) {
@@ -1006,6 +1006,10 @@
 			read_buf = fwd_info->buf_2->data;
 			read_len = fwd_info->buf_2->len;
 		}
+		if (read_buf) {
+			temp_buf = fwd_info->buf_2;
+			atomic_set(&temp_buf->in_busy, 1);
+		}
 	} else {
 		pr_debug("diag: In %s, both buffers are empty for p: %d, t: %d\n",
 			 __func__, fwd_info->peripheral, fwd_info->type);