/* * Copyright (c) 2013 * Phillip Lougher * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. */ #include #include #include #include "page_actor.h" /* * This file contains implementations of page_actor for decompressing into * an intermediate buffer, and for decompressing directly into the * page cache. * * Calling code should avoid sleeping between calls to squashfs_first_page() * and squashfs_finish_page(). */ /* Implementation of page_actor for decompressing into intermediate buffer */ static void *cache_first_page(struct squashfs_page_actor *actor) { actor->next_page = 1; return actor->buffer[0]; } static void *cache_next_page(struct squashfs_page_actor *actor) { if (actor->next_page == actor->pages) return NULL; return actor->buffer[actor->next_page++]; } static void cache_finish_page(struct squashfs_page_actor *actor) { /* empty */ } struct squashfs_page_actor *squashfs_page_actor_init(void **buffer, int pages, int length) { struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL); if (actor == NULL) return NULL; actor->length = length ? : pages * PAGE_SIZE; actor->buffer = buffer; actor->pages = pages; actor->next_page = 0; actor->squashfs_first_page = cache_first_page; actor->squashfs_next_page = cache_next_page; actor->squashfs_finish_page = cache_finish_page; return actor; } /* Implementation of page_actor for decompressing directly into page cache. */ static void *direct_first_page(struct squashfs_page_actor *actor) { actor->next_page = 1; return actor->pageaddr = kmap_atomic(actor->page[0]); } static void *direct_next_page(struct squashfs_page_actor *actor) { if (actor->pageaddr) kunmap_atomic(actor->pageaddr); return actor->pageaddr = actor->next_page == actor->pages ? NULL : kmap_atomic(actor->page[actor->next_page++]); } static void direct_finish_page(struct squashfs_page_actor *actor) { if (actor->pageaddr) kunmap_atomic(actor->pageaddr); } struct squashfs_page_actor *squashfs_page_actor_init_special(struct page **page, int pages, int length) { struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL); if (actor == NULL) return NULL; actor->length = length ? : pages * PAGE_SIZE; actor->page = page; actor->pages = pages; actor->next_page = 0; actor->pageaddr = NULL; actor->squashfs_first_page = direct_first_page; actor->squashfs_next_page = direct_next_page; actor->squashfs_finish_page = direct_finish_page; return actor; } '>committer
path: root/tools/usb/usbip
diff options
context:
space:
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 /tools/usb/usbip
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 'tools/usb/usbip')