/* * u_f.h * * Utility definitions for USB 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_F_H__ #define __U_F_H__ #include /* Variable Length Array Macros **********************************************/ #define vla_group(groupname) size_t groupname##__next = 0 #define vla_group_size(groupname) groupname##__next #define vla_item(groupname, type, name, n) \ size_t groupname##_##name##__offset = ({ \ size_t align_mask = __alignof__(type) - 1; \ size_t offset = (groupname##__next + align_mask) & ~align_mask;\ size_t size = (n) * sizeof(type); \ groupname##__next = offset + size; \ offset; \ }) #define vla_item_with_sz(groupname, type, name, n) \ size_t groupname##_##name##__sz = (n) * sizeof(type); \ size_t groupname##_##name##__offset = ({ \ size_t align_mask = __alignof__(type) - 1; \ size_t offset = (groupname##__next + align_mask) & ~align_mask;\ size_t size = groupname##_##name##__sz; \ groupname##__next = offset + size; \ offset; \ }) #define vla_ptr(ptr, groupname, name) \ ((void *) ((char *)ptr + groupname##_##name##__offset)) struct usb_ep; struct usb_request; /** * alloc_ep_req - returns a usb_request allocated by the gadget driver and * allocates the request's buffer. * * @ep: the endpoint to allocate a usb_request * @len: usb_requests's buffer suggested size * * In case @ep direction is OUT, the @len will be aligned to ep's * wMaxPacketSize. In order to avoid memory leaks or drops, *always* use * usb_requests's length (req->length) to refer to the allocated buffer size. * Requests allocated via alloc_ep_req() *must* be freed by free_ep_req(). */ struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len); /* Frees a usb_request previously allocated by alloc_ep_req() */ static inline void free_ep_req(struct usb_ep *ep, struct usb_request *req) { kfree(req->buf); usb_ep_free_request(ep, req); } #endif /* __U_F_H__ */
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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/time
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/time')