On Thu, Apr 07, 2022 at 10:45:14AM +0800, Tao Wang wrote:
> The shared_hcd->hcd_priv is not used in xhci, so not
> need to malloc hcd priv memory for shared_hcd.
What is the problem with allocating that memory? Do you have systems
with thousands of USB host controllers where this memory is wasted?
> This change add a shared_hcd_no_priv flag to indicate
> if shared_hcd use priv, and set the flag of xhci to 1.
1 is not a boolean :(
>
> Signed-off-by: Tao Wang <quic_wat@xxxxxxxxxxx>
> ---
> drivers/usb/core/hcd.c | 6 +++++-
> drivers/usb/host/xhci-plat.c | 1 +
> include/linux/usb/hcd.h | 1 +
> 3 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
> index 99908d8..f339c3e 100644
> --- a/drivers/usb/core/hcd.c
> +++ b/drivers/usb/core/hcd.c
> @@ -2419,7 +2419,11 @@ struct usb_hcd *__usb_create_hcd(const struct hc_driver *driver,
> {
> struct usb_hcd *hcd;
>
> - hcd = kzalloc(sizeof(*hcd) + driver->hcd_priv_size, GFP_KERNEL);
> + if (primary_hcd && driver->shared_hcd_no_priv)
> + hcd = kzalloc(sizeof(*hcd), GFP_KERNEL);
> + else
> + hcd = kzalloc(sizeof(*hcd) + driver->hcd_priv_size, GFP_KERNEL);
> +
> if (!hcd)
> return NULL;
> if (primary_hcd == NULL) {
> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> index 21280a6..223e508 100644
> --- a/drivers/usb/host/xhci-plat.c
> +++ b/drivers/usb/host/xhci-plat.c
> @@ -236,6 +236,7 @@ static int xhci_plat_probe(struct platform_device *pdev)
> return -ENODEV;
>
> driver = &xhci_plat_hc_driver;
> + driver->shared_hcd_no_priv = 1;
true?
>
> irq = platform_get_irq(pdev, 0);
> if (irq < 0)
> diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
> index 2ffafbd..03ac312 100644
> --- a/include/linux/usb/hcd.h
> +++ b/include/linux/usb/hcd.h
> @@ -256,6 +256,7 @@ struct hc_driver {
> const char *description; /* "ehci-hcd" etc */
> const char *product_desc; /* product/vendor string */
> size_t hcd_priv_size; /* size of private data */
> + bool shared_hcd_no_priv; /* 0 use priv, 1 not use priv*/
Did you check to see how much extra padding you just added to the
structure? When writing a change to try to save memory, do not cause
extra memory to be wasted for everyone.
thanks,
greg k-h
