Re: [PATCH] USB: dwc3: remove debugfs root dentry storage

Peter Chen
2021-06-10T01:14:32Z

On 21-06-09 11:39:24, Greg Kroah-Hartman wrote:
> 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@kernel.org>
> Cc: Jack Pham <jackp@codeaurora.org>
> Cc: Peter Chen <peter.chen@kernel.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Reviewed-by: Peter Chen <peter.chen@kernel.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
>

--

Thanks,
Peter Chen