/* * Scatter-Gather buffer * * Copyright (c) by Takashi Iwai * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * 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 * */ #include #include #include #include #include /* table entries are align to 32 */ #define SGBUF_TBL_ALIGN 32 #define sgbuf_align_table(tbl) ALIGN((tbl), SGBUF_TBL_ALIGN) int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab) { struct snd_sg_buf *sgbuf = dmab->private_data; struct snd_dma_buffer tmpb; int i; if (! sgbuf) return -EINVAL; vunmap(dmab->area); dmab->area = NULL; tmpb.dev.type = SNDRV_DMA_TYPE_DEV; tmpb.dev.dev = sgbuf->dev; for (i = 0; i < sgbuf->pages; i++) { if (!(sgbuf->table[i].addr & ~PAGE_MASK)) continue; /* continuous pages */ tmpb.area = sgbuf->table[i].buf; tmpb.addr = sgbuf->table[i].addr & PAGE_MASK; tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT; snd_dma_free_pages(&tmpb); } kfree(sgbuf->table); kfree(sgbuf->page_table); kfree(sgbuf); dmab->private_data = NULL; return 0; } #define MAX_ALLOC_PAGES 32 void *snd_malloc_sgbuf_pages(struct device *device, size_t size, struct snd_dma_buffer *dmab, size_t *res_size) { struct snd_sg_buf *sgbuf; unsigned int i, pages, chunk, maxpages; struct snd_dma_buffer tmpb; struct snd_sg_page *table; struct page **pgtable; dmab->area = NULL; dmab->addr = 0; dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL); if (! sgbuf) return NULL; sgbuf->dev = device; pages = snd_sgbuf_aligned_pages(size); sgbuf->tblsize = sgbuf_align_table(pages); table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL); if (!table) goto _failed; sgbuf->table = table; pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL); if (!pgtable) goto _failed; sgbuf->page_table = pgtable; /* allocate pages */ maxpages = MAX_ALLOC_PAGES; while (pages > 0) { chunk = pages; /* don't be too eager to take a huge chunk */ if (chunk > maxpages) chunk = maxpages; chunk <<= PAGE_SHIFT; if (snd_dma_alloc_pages_fallback(SNDRV_DMA_TYPE_DEV, device, chunk, &tmpb) < 0) { if (!sgbuf->pages) goto _failed; if (!res_size) goto _failed; size = sgbuf->pages * PAGE_SIZE; break; } chunk = tmpb.bytes >> PAGE_SHIFT; for (i = 0; i < chunk; i++) { table->buf = tmpb.area; table->addr = tmpb.addr; if (!i) table->addr |= chunk; /* mark head */ table++; *pgtable++ = virt_to_page(tmpb.area); tmpb.area += PAGE_SIZE; tmpb.addr += PAGE_SIZE; } sgbuf->pages += chunk; pages -= chunk; if (chunk < maxpages) maxpages = chunk; } sgbuf->size = size; dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL); if (! dmab->area) goto _failed; if (res_size) *res_size = sgbuf->size; return dmab->area; _failed: snd_free_sgbuf_pages(dmab); /* free the table */ return NULL; } /* * compute the max chunk size with continuous pages on sg-buffer */ unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab, unsigned int ofs, unsigned int size) { struct snd_sg_buf *sg = dmab->private_data; unsigned int start, end, pg; start = ofs >> PAGE_SHIFT; end = (ofs + size - 1) >> PAGE_SHIFT; /* check page continuity */ pg = sg->table[start].addr >> PAGE_SHIFT; for (;;) { start++; if (start > end) break; pg++; if ((sg->table[start].addr >> PAGE_SHIFT) != pg) return (start << PAGE_SHIFT) - ofs; } /* ok, all on continuous pages */ return size; } EXPORT_SYMBOL(snd_sgbuf_get_chunk_size); value='9'>9space:mode:
authorDouglas Miller <dougmill@linux.vnet.ibm.com>2017-01-28 06:42:20 -0600
committerTejun Heo <tj@kernel.org>2017-01-28 07:49:42 -0500
commit966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /sound/soc/amd/acp-pcm-dma.c
parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'sound/soc/amd/acp-pcm-dma.c')