/* * Copyright (C) 2012 Fusion-io All rights reserved. * Copyright (C) 2012 Intel Corp. All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License v2 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 021110-1307, USA. */ #ifndef __BTRFS_RAID56__ #define __BTRFS_RAID56__ static inline int nr_parity_stripes(struct map_lookup *map) { if (map->type & BTRFS_BLOCK_GROUP_RAID5) return 1; else if (map->type & BTRFS_BLOCK_GROUP_RAID6) return 2; else return 0; } static inline int nr_data_stripes(struct map_lookup *map) { return map->num_stripes - nr_parity_stripes(map); } #define RAID5_P_STRIPE ((u64)-2) #define RAID6_Q_STRIPE ((u64)-1) #define is_parity_stripe(x) (((x) == RAID5_P_STRIPE) || \ ((x) == RAID6_Q_STRIPE)) struct btrfs_raid_bio; struct btrfs_device; int raid56_parity_recover(struct btrfs_fs_info *fs_info, struct bio *bio, struct btrfs_bio *bbio, u64 stripe_len, int mirror_num, int generic_io); int raid56_parity_write(struct btrfs_fs_info *fs_info, struct bio *bio, struct btrfs_bio *bbio, u64 stripe_len); void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page, u64 logical); struct btrfs_raid_bio * raid56_parity_alloc_scrub_rbio(struct btrfs_fs_info *fs_info, struct bio *bio, struct btrfs_bio *bbio, u64 stripe_len, struct btrfs_device *scrub_dev, unsigned long *dbitmap, int stripe_nsectors); void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio); struct btrfs_raid_bio * raid56_alloc_missing_rbio(struct btrfs_fs_info *fs_info, struct bio *bio, struct btrfs_bio *bbio, u64 length); void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio); int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info); void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info); #endif 44dc3341'/>
path: root/include/drm/drm_os_linux.h
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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 /include/drm/drm_os_linux.h
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 'include/drm/drm_os_linux.h')