linux-kernel - [PATCH] USB: dwc3: remove debugfs root dentry storage

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Date:   Wed,  9 Jun 2021 11:39:24 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-usb@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Felipe Balbi <balbi@...nel.org>,
        Jack Pham <jackp@...eaurora.org>,
        Peter Chen <peter.chen@...nel.org>
Subject: [PATCH] USB: dwc3: remove debugfs root dentry storage

There is no need to keep around the debugfs "root" directory for the
dwc3 device.  Instead, look it up anytime we need to find it.  This will
help when callers get out-of-order and we had the potential to have a
"stale" pointer around for the root dentry, as has happened in the past.

Cc: Felipe Balbi <balbi@...nel.org>
Cc: Jack Pham <jackp@...eaurora.org>
Cc: Peter Chen <peter.chen@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/usb/dwc3/core.h    | 2 --
 drivers/usb/dwc3/debugfs.c | 8 ++++----
 drivers/usb/dwc3/gadget.c  | 4 +++-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index c5d5760cdf53..dccdf13b5f9e 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1013,7 +1013,6 @@ struct dwc3_scratchpad_array {
  * @link_state: link state
  * @speed: device speed (super, high, full, low)
  * @hwparams: copy of hwparams registers
- * @root: debugfs root folder pointer
  * @regset: debugfs pointer to regdump file
  * @dbg_lsp_select: current debug lsp mux register selection
  * @test_mode: true when we're entering a USB test mode
@@ -1222,7 +1221,6 @@ struct dwc3 {
 	u8			num_eps;
 
 	struct dwc3_hwparams	hwparams;
-	struct dentry		*root;
 	struct debugfs_regset32	*regset;
 
 	u32			dbg_lsp_select;
diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
index 5dbbe53269d3..f2b7675c7f62 100644
--- a/drivers/usb/dwc3/debugfs.c
+++ b/drivers/usb/dwc3/debugfs.c
@@ -889,8 +889,10 @@ static void dwc3_debugfs_create_endpoint_files(struct dwc3_ep *dep,
 void dwc3_debugfs_create_endpoint_dir(struct dwc3_ep *dep)
 {
 	struct dentry		*dir;
+	struct dentry		*root;
 
-	dir = debugfs_create_dir(dep->name, dep->dwc->root);
+	root = debugfs_lookup(dev_name(dep->dwc->dev), usb_debug_root);
+	dir = debugfs_create_dir(dep->name, root);
 	dwc3_debugfs_create_endpoint_files(dep, dir);
 }
 
@@ -909,8 +911,6 @@ void dwc3_debugfs_init(struct dwc3 *dwc)
 	dwc->regset->base = dwc->regs - DWC3_GLOBALS_REGS_START;
 
 	root = debugfs_create_dir(dev_name(dwc->dev), usb_debug_root);
-	dwc->root = root;
-
 	debugfs_create_regset32("regdump", 0444, root, dwc->regset);
 	debugfs_create_file("lsp_dump", 0644, root, dwc, &dwc3_lsp_fops);
 
@@ -929,6 +929,6 @@ void dwc3_debugfs_init(struct dwc3 *dwc)
 
 void dwc3_debugfs_exit(struct dwc3 *dwc)
 {
-	debugfs_remove_recursive(dwc->root);
+	debugfs_remove(debugfs_lookup(dev_name(dwc->dev), usb_debug_root));
 	kfree(dwc->regset);
 }
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 7cc99b6d0bfe..026a2ad0fc80 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2799,7 +2799,9 @@ static void dwc3_gadget_free_endpoints(struct dwc3 *dwc)
 			list_del(&dep->endpoint.ep_list);
 		}
 
-		debugfs_remove_recursive(debugfs_lookup(dep->name, dwc->root));
+		debugfs_remove_recursive(debugfs_lookup(dep->name,
+				debugfs_lookup(dev_name(dep->dwc->dev),
+					       usb_debug_root)));
 		kfree(dep);
 	}
 }
-- 
2.32.0