/* * u_ether_configfs.h * * Utility definitions for configfs support in USB Ethernet functions * * Copyright (c) 2013 Samsung Electronics Co., Ltd. * http://www.samsung.com * * Author: Andrzej Pietrasiewicz * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #ifndef __U_ETHER_CONFIGFS_H #define __U_ETHER_CONFIGFS_H #define USB_ETHERNET_CONFIGFS_ITEM(_f_) \ static void _f_##_attr_release(struct config_item *item) \ { \ struct f_##_f_##_opts *opts = to_f_##_f_##_opts(item); \ \ usb_put_function_instance(&opts->func_inst); \ } \ \ static struct configfs_item_operations _f_##_item_ops = { \ .release = _f_##_attr_release, \ } #define USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(_f_) \ static ssize_t _f_##_opts_dev_addr_show(struct config_item *item, \ char *page) \ { \ struct f_##_f_##_opts *opts = to_f_##_f_##_opts(item); \ int result; \ \ mutex_lock(&opts->lock); \ result = gether_get_dev_addr(opts->net, page, PAGE_SIZE); \ mutex_unlock(&opts->lock); \ \ return result; \ } \ \ static ssize_t _f_##_opts_dev_addr_store(struct config_item *item, \ const char *page, size_t len)\ { \ struct f_##_f_##_opts *opts = to_f_##_f_##_opts(item); \ int ret; \ \ mutex_lock(&opts->lock); \ if (opts->refcnt) { \ mutex_unlock(&opts->lock); \ return -EBUSY; \ } \ \ ret = gether_set_dev_addr(opts->net, page); \ mutex_unlock(&opts->lock); \ if (!ret) \ ret = len; \ return ret; \ } \ \ CONFIGFS_ATTR(_f_##_opts_, dev_addr) #define USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(_f_) \ static ssize_t _f_##_opts_host_addr_show(struct config_item *item, \ char *page) \ { \ struct f_##_f_##_opts *opts = to_f_##_f_##_opts(item); \ int result; \ \ mutex_lock(&opts->lock); \ result = gether_get_host_addr(opts->net, page, PAGE_SIZE); \ mutex_unlock(&opts->lock); \ \ return result; \ } \ \ static ssize_t _f_##_opts_host_addr_store(struct config_item *item, \ const char *page, size_t len)\ { \ struct f_##_f_##_opts *opts = to_f_##_f_##_opts(item); \ int ret; \ \ mutex_lock(&opts->lock); \ if (opts->refcnt) { \ mutex_unlock(&opts->lock); \ return -EBUSY; \ } \ \ ret = gether_set_host_addr(opts->net, page); \ mutex_unlock(&opts->lock); \ if (!ret) \ ret = len; \ return ret; \ } \ \ CONFIGFS_ATTR(_f_##_opts_, host_addr) #define USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(_f_) \ static ssize_t _f_##_opts_qmult_show(struct config_item *item, \ char *page) \ { \ struct f_##_f_##_opts *opts = to_f_##_f_##_opts(item); \ unsigned qmult; \ \ mutex_lock(&opts->lock); \ qmult = gether_get_qmult(opts->net); \ mutex_unlock(&opts->lock); \ return sprintf(page, "%d", qmult); \ } \ \ static ssize_t _f_##_opts_qmult_store(struct config_item *item, \ const char *page, size_t len)\ { \ struct f_##_f_##_opts *opts = to_f_##_f_##_opts(item); \ u8 val; \ int ret; \ \ mutex_lock(&opts->lock); \ if (opts->refcnt) { \ ret = -EBUSY; \ goto out; \ } \ \ ret = kstrtou8(page, 0, &val); \ if (ret) \ goto out; \ \ gether_set_qmult(opts->net, val); \ ret = len; \ out: \ mutex_unlock(&opts->lock); \ return ret; \ } \ \ CONFIGFS_ATTR(_f_##_opts_, qmult) #define USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(_f_) \ static ssize_t _f_##_opts_ifname_show(struct config_item *item, \ char *page) \ { \ struct f_##_f_##_opts *opts = to_f_##_f_##_opts(item); \ int ret; \ \ mutex_lock(&opts->lock); \ ret = gether_get_ifname(opts->net, page, PAGE_SIZE); \ mutex_unlock(&opts->lock); \ \ return ret; \ } \ \ CONFIGFS_ATTR_RO(_f_##_opts_, ifname) #endif /* __U_ETHER_CONFIGFS_H */ ;'>mode:
authorIago Abal <mail@iagoabal.eu>2017-01-11 14:00:21 +0100
committerVinod Koul <vinod.koul@intel.com>2017-01-25 15:35:11 +0530
commit91539eb1fda2d530d3b268eef542c5414e54bf1a (patch)
tree960f5ca6342ad20837aff18aad6e8ecd7da32fd6 /kernel/rcu/tree_plugin.h
parent6610d0edf6dc7ee97e46ab3a538a565c79d26199 (diff)
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the following double-lock bug: Double lock: 1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236; 2. call to function `pl330_release_channel' immediately after; 3. call to function `dma_pl330_rqcb' in line 1753; 4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505. I have fixed it as suggested by Marek Szyprowski. First, I have replaced `pch->lock' with `pl330->lock' in functions `pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids the double-lock by acquiring a different lock than `dma_pl330_rqcb'. NOTE that, as a result, `pl330_free_chan_resources' executes `list_splice_tail_init' on `pch->work_list' under lock `pl330->lock', whereas in the rest of the code `pch->work_list' is protected by `pch->lock'. I don't know if this may cause race conditions. Similarly `pch->cyclic' is written by `pl330_alloc_chan_resources' under `pl330->lock' but read by `pl330_tx_submit' under `pch->lock'. Second, I have removed locking from `pl330_request_channel' and `pl330_release_channel' functions. Function `pl330_request_channel' is only called from `pl330_alloc_chan_resources', so the lock is already held. Function `pl330_release_channel' is called from `pl330_free_chan_resources', which already holds the lock, and from `pl330_del'. Function `pl330_del' is called in an error path of `pl330_probe' and at the end of `pl330_remove', but I assume that there cannot be concurrent accesses to the protected data at those points. Signed-off-by: Iago Abal <mail@iagoabal.eu> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'kernel/rcu/tree_plugin.h')