From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- drivers/usb/gadget/functions.c | 117 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100644 drivers/usb/gadget/functions.c (limited to 'drivers/usb/gadget/functions.c') diff --git a/drivers/usb/gadget/functions.c b/drivers/usb/gadget/functions.c new file mode 100644 index 000000000..203361a64 --- /dev/null +++ b/drivers/usb/gadget/functions.c @@ -0,0 +1,117 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include + +#include + +static LIST_HEAD(func_list); +static DEFINE_MUTEX(func_lock); + +static struct usb_function_instance *try_get_usb_function_instance(const char *name) +{ + struct usb_function_driver *fd; + struct usb_function_instance *fi; + + fi = ERR_PTR(-ENOENT); + mutex_lock(&func_lock); + list_for_each_entry(fd, &func_list, list) { + + if (strcmp(name, fd->name)) + continue; + + if (!try_module_get(fd->mod)) { + fi = ERR_PTR(-EBUSY); + break; + } + fi = fd->alloc_inst(); + if (IS_ERR(fi)) + module_put(fd->mod); + else + fi->fd = fd; + break; + } + mutex_unlock(&func_lock); + return fi; +} + +struct usb_function_instance *usb_get_function_instance(const char *name) +{ + struct usb_function_instance *fi; + int ret; + + fi = try_get_usb_function_instance(name); + if (!IS_ERR(fi)) + return fi; + ret = PTR_ERR(fi); + if (ret != -ENOENT) + return fi; + ret = request_module("usbfunc:%s", name); + if (ret < 0) + return ERR_PTR(ret); + return try_get_usb_function_instance(name); +} +EXPORT_SYMBOL_GPL(usb_get_function_instance); + +struct usb_function *usb_get_function(struct usb_function_instance *fi) +{ + struct usb_function *f; + + f = fi->fd->alloc_func(fi); + if (IS_ERR(f)) + return f; + f->fi = fi; + return f; +} +EXPORT_SYMBOL_GPL(usb_get_function); + +void usb_put_function_instance(struct usb_function_instance *fi) +{ + struct module *mod; + + if (!fi) + return; + + mod = fi->fd->mod; + fi->free_func_inst(fi); + module_put(mod); +} +EXPORT_SYMBOL_GPL(usb_put_function_instance); + +void usb_put_function(struct usb_function *f) +{ + if (!f) + return; + + f->free_func(f); +} +EXPORT_SYMBOL_GPL(usb_put_function); + +int usb_function_register(struct usb_function_driver *newf) +{ + struct usb_function_driver *fd; + int ret; + + ret = -EEXIST; + + mutex_lock(&func_lock); + list_for_each_entry(fd, &func_list, list) { + if (!strcmp(fd->name, newf->name)) + goto out; + } + ret = 0; + list_add_tail(&newf->list, &func_list); +out: + mutex_unlock(&func_lock); + return ret; +} +EXPORT_SYMBOL_GPL(usb_function_register); + +void usb_function_unregister(struct usb_function_driver *fd) +{ + mutex_lock(&func_lock); + list_del(&fd->list); + mutex_unlock(&func_lock); +} +EXPORT_SYMBOL_GPL(usb_function_unregister); -- cgit v1.3.1