commit 8565697db9129533be6efb82eb4efc9da1e611ad
author Manoj Prabhu B <bmanoj@codeaurora.org> Fri Jun 14 10:53:40 2019 +0530
committer Manoj Prabhu B <bmanoj@codeaurora.org> Fri Jun 14 10:53:40 2019 +0530
tree ba6679a40b0883925915ceb3c14e6ea2952c4da4
parent 91c82cb6b195cff612f7921102cd3899e7cfe2cd

diag: Prevent switching mode for non mdlog process

Switching the mode between USB and PCIE is incorrectly happening
while closing non mdlog process. Patch prevents this issue case
for non mdlog process by checking against the pid of the process
which caused the switch between USB and PCIE.

Change-Id: I609076633fe9dd20287cfc35f0098004bdd11618
Signed-off-by: Manoj Prabhu B <bmanoj@codeaurora.org>

drivers/char/diag/diagchar.h

diff --git a/drivers/char/diag/diagchar.h b/drivers/char/diag/diagchar.h
index 36adaa9..7ef332f 100644
--- a/drivers/char/diag/diagchar.h
+++ b/drivers/char/diag/diagchar.h
@@ -656,6 +656,7 @@
 	int usb_connected;
 #endif
 	int pcie_connected;
+	int pcie_switch_pid;
 	struct workqueue_struct *diag_wq;
 	struct work_struct diag_drain_work;
 	struct work_struct update_user_clients;

drivers/char/diag/diagchar_core.c

diff --git a/drivers/char/diag/diagchar_core.c b/drivers/char/diag/diagchar_core.c
index 47da553..e2382a3 100644
--- a/drivers/char/diag/diagchar_core.c
+++ b/drivers/char/diag/diagchar_core.c
@@ -460,15 +460,19 @@
 	session_info = diag_md_session_get_pid(pid);
 	if (!session_info) {
 		mutex_unlock(&driver->md_session_lock);
-		if (driver->pcie_transport_def == DIAG_ROUTE_TO_PCIE)
-			params.req_mode = PCIE_MODE;
-		else
-			params.req_mode = USB_MODE;
-		params.mode_param = 0;
-		params.pd_mask = 0;
-		params.peripheral_mask = DIAG_CON_ALL;
 		mutex_lock(&driver->diagchar_mutex);
-		diag_switch_logging(&params);
+		if (driver->pcie_switch_pid == pid) {
+			if (driver->pcie_transport_def ==
+				DIAG_ROUTE_TO_PCIE)
+				params.req_mode = PCIE_MODE;
+			else
+				params.req_mode = USB_MODE;
+			params.mode_param = 0;
+			params.pd_mask = 0;
+			params.peripheral_mask = DIAG_CON_ALL;
+			diag_switch_logging(&params);
+			driver->pcie_switch_pid = 0;
+		}
 		mutex_unlock(&driver->diagchar_mutex);
 		return;
 	}
@@ -1895,6 +1899,17 @@
 	}
 	driver->logging_mode = new_mode;
 	driver->logging_mask = peripheral_mask;
+	if (((curr_mode == DIAG_PCIE_MODE && new_mode == DIAG_USB_MODE) ||
+		(curr_mode == DIAG_USB_MODE && new_mode == DIAG_PCIE_MODE)) &&
+		!driver->pcie_switch_pid) {
+		/*
+		 * Store the pid of process affecting switch
+		 * from USB to PCIE or vice versa to help
+		 * close only this process while closing
+		 * logging process.
+		 */
+		driver->pcie_switch_pid = current->tgid;
+	}
 	if (new_mode == DIAG_PCIE_MODE) {
 		driver->transport_set = DIAG_ROUTE_TO_PCIE;
 		diagmem_setsize(POOL_TYPE_MUX_APPS, itemsize_pcie_apps,
@@ -4204,6 +4219,7 @@
 	driver->mask_check = 0;
 	driver->in_busy_pktdata = 0;
 	driver->in_busy_dcipktdata = 0;
+	driver->pcie_switch_pid = 0;
 	driver->rsp_buf_ctxt = SET_BUF_CTXT(APPS_DATA, TYPE_CMD, 1);
 	hdlc_data.ctxt = SET_BUF_CTXT(APPS_DATA, TYPE_DATA, 1);
 	hdlc_data.len = 0;