/****************************************************************************** AudioScience HPI driver Copyright (C) 1997-2012 AudioScience Inc. This program is free software; you can redistribute it and/or modify it under the terms of version 2 of the GNU General Public License as published by the Free Software Foundation; This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA HPI Operating System function implementation for Linux (C) Copyright AudioScience Inc. 1997-2003 ******************************************************************************/ #define SOURCEFILE_NAME "hpios.c" #include "hpi_internal.h" #include "hpidebug.h" #include #include void hpios_delay_micro_seconds(u32 num_micro_sec) { if ((usecs_to_jiffies(num_micro_sec) > 1) && !in_interrupt()) { /* MUST NOT SCHEDULE IN INTERRUPT CONTEXT! */ schedule_timeout_uninterruptible(usecs_to_jiffies (num_micro_sec)); } else if (num_micro_sec <= 2000) udelay(num_micro_sec); else mdelay(num_micro_sec / 1000); } /** Allocate an area of locked memory for bus master DMA operations. If allocation fails, return 1, and *pMemArea.size = 0 */ u16 hpios_locked_mem_alloc(struct consistent_dma_area *p_mem_area, u32 size, struct pci_dev *pdev) { /*?? any benefit in using managed dmam_alloc_coherent? */ p_mem_area->vaddr = dma_alloc_coherent(&pdev->dev, size, &p_mem_area->dma_handle, GFP_DMA32 | GFP_KERNEL); if (p_mem_area->vaddr) { HPI_DEBUG_LOG(DEBUG, "allocated %d bytes, dma 0x%x vma %p\n", size, (unsigned int)p_mem_area->dma_handle, p_mem_area->vaddr); p_mem_area->pdev = &pdev->dev; p_mem_area->size = size; return 0; } else { HPI_DEBUG_LOG(WARNING, "failed to allocate %d bytes locked memory\n", size); p_mem_area->size = 0; return 1; } } u16 hpios_locked_mem_free(struct consistent_dma_area *p_mem_area) { if (p_mem_area->size) { dma_free_coherent(p_mem_area->pdev, p_mem_area->size, p_mem_area->vaddr, p_mem_area->dma_handle); HPI_DEBUG_LOG(DEBUG, "freed %lu bytes, dma 0x%x vma %p\n", (unsigned long)p_mem_area->size, (unsigned int)p_mem_area->dma_handle, p_mem_area->vaddr); p_mem_area->size = 0; return 0; } else { return 1; } } n>
path: root/net/llc/llc_pdu.c
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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 /net/llc/llc_pdu.c
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 'net/llc/llc_pdu.c')