From: Alan Stern <stern@rowland.harvard.edu>
To: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
linux-usb@vger.kernel.org
Subject: Re: [PATCH] usb: core: Remove the useless struct usb_devmap which is just a bitmap
Date: Sat, 4 May 2024 09:59:12 -0400 [thread overview]
Message-ID: <1126b27f-c672-4d13-b4ce-baf720624823@rowland.harvard.edu> (raw)
In-Reply-To: <1d818575ff7a1e8317674aecf761ee23c89fdc84.1714815990.git.christophe.jaillet@wanadoo.fr>
On Sat, May 04, 2024 at 11:47:05AM +0200, Christophe JAILLET wrote:
> struct usb_devmap is really just a bitmap. No need to have a dedicated
> structure for that.
>
> Simplify code and use DECLARE_BITMAP() directly instead.
>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> Compile tested only.
>
> I've re-used the comment related to struct usb_devmap for the devmap field
> in struct usb_bus, because it sounds better to me.
> ---
Acked-by: Alan Stern <stern@rowland.harvard.edu>
> drivers/usb/core/hcd.c | 4 ++--
> drivers/usb/core/hub.c | 9 ++++-----
> include/linux/usb.h | 7 +------
> 3 files changed, 7 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
> index c0e005670d67..e3366f4d82b9 100644
> --- a/drivers/usb/core/hcd.c
> +++ b/drivers/usb/core/hcd.c
> @@ -866,7 +866,7 @@ static int usb_rh_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
> */
> static void usb_bus_init (struct usb_bus *bus)
> {
> - memset (&bus->devmap, 0, sizeof(struct usb_devmap));
> + memset(&bus->devmap, 0, sizeof(bus->devmap));
>
> bus->devnum_next = 1;
>
> @@ -962,7 +962,7 @@ static int register_root_hub(struct usb_hcd *hcd)
>
> usb_dev->devnum = devnum;
> usb_dev->bus->devnum_next = devnum + 1;
> - set_bit (devnum, usb_dev->bus->devmap.devicemap);
> + set_bit(devnum, usb_dev->bus->devmap);
> usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
>
> mutex_lock(&usb_bus_idr_lock);
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 8939f1410644..4b93c0bd1d4b 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -2207,13 +2207,12 @@ static void choose_devnum(struct usb_device *udev)
> mutex_lock(&bus->devnum_next_mutex);
>
> /* Try to allocate the next devnum beginning at bus->devnum_next. */
> - devnum = find_next_zero_bit(bus->devmap.devicemap, 128,
> - bus->devnum_next);
> + devnum = find_next_zero_bit(bus->devmap, 128, bus->devnum_next);
> if (devnum >= 128)
> - devnum = find_next_zero_bit(bus->devmap.devicemap, 128, 1);
> + devnum = find_next_zero_bit(bus->devmap, 128, 1);
> bus->devnum_next = (devnum >= 127 ? 1 : devnum + 1);
> if (devnum < 128) {
> - set_bit(devnum, bus->devmap.devicemap);
> + set_bit(devnum, bus->devmap);
> udev->devnum = devnum;
> }
> mutex_unlock(&bus->devnum_next_mutex);
> @@ -2222,7 +2221,7 @@ static void choose_devnum(struct usb_device *udev)
> static void release_devnum(struct usb_device *udev)
> {
> if (udev->devnum > 0) {
> - clear_bit(udev->devnum, udev->bus->devmap.devicemap);
> + clear_bit(udev->devnum, udev->bus->devmap);
> udev->devnum = -1;
> }
> }
> diff --git a/include/linux/usb.h b/include/linux/usb.h
> index 9e52179872a5..1913a13833f2 100644
> --- a/include/linux/usb.h
> +++ b/include/linux/usb.h
> @@ -440,11 +440,6 @@ int __usb_get_extra_descriptor(char *buffer, unsigned size,
>
> /* ----------------------------------------------------------------------- */
>
> -/* USB device number allocation bitmap */
> -struct usb_devmap {
> - unsigned long devicemap[128 / (8*sizeof(unsigned long))];
> -};
> -
> /*
> * Allocated per bus (tree of devices) we have:
> */
> @@ -472,7 +467,7 @@ struct usb_bus {
> * round-robin allocation */
> struct mutex devnum_next_mutex; /* devnum_next mutex */
>
> - struct usb_devmap devmap; /* device address allocation map */
> + DECLARE_BITMAP(devmap, 128); /* USB device number allocation bitmap */
> struct usb_device *root_hub; /* Root hub */
> struct usb_bus *hs_companion; /* Companion EHCI bus, if any */
>
> --
> 2.45.0
>
>
prev parent reply other threads:[~2024-05-04 13:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-04 9:47 [PATCH] usb: core: Remove the useless struct usb_devmap which is just a bitmap Christophe JAILLET
2024-05-04 13:59 ` Alan Stern [this message]
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