mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-28 11:18:45 +07:00
97d052ea3f
- Untangle the header spaghetti which causes build failures in various situations caused by the lockdep additions to seqcount to validate that the write side critical sections are non-preemptible. - The seqcount associated lock debug addons which were blocked by the above fallout. seqcount writers contrary to seqlock writers must be externally serialized, which usually happens via locking - except for strict per CPU seqcounts. As the lock is not part of the seqcount, lockdep cannot validate that the lock is held. This new debug mechanism adds the concept of associated locks. sequence count has now lock type variants and corresponding initializers which take a pointer to the associated lock used for writer serialization. If lockdep is enabled the pointer is stored and write_seqcount_begin() has a lockdep assertion to validate that the lock is held. Aside of the type and the initializer no other code changes are required at the seqcount usage sites. The rest of the seqcount API is unchanged and determines the type at compile time with the help of _Generic which is possible now that the minimal GCC version has been moved up. Adding this lockdep coverage unearthed a handful of seqcount bugs which have been addressed already independent of this. While generaly useful this comes with a Trojan Horse twist: On RT kernels the write side critical section can become preemtible if the writers are serialized by an associated lock, which leads to the well known reader preempts writer livelock. RT prevents this by storing the associated lock pointer independent of lockdep in the seqcount and changing the reader side to block on the lock when a reader detects that a writer is in the write side critical section. - Conversion of seqcount usage sites to associated types and initializers. -----BEGIN PGP SIGNATURE----- iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAl8xmPYTHHRnbHhAbGlu dXRyb25peC5kZQAKCRCmGPVMDXSYoTuQEACyzQCjU8PgehPp9oMqWzaX2fcVyuZO QU2yw6gmz2oTz3ZHUNwdW8UnzGh2OWosK3kDruoD9FtSS51lER1/ISfSPCGfyqxC KTjOcB1Kvxwq/3LcCx7Zi3ZxWApat74qs3EhYhKtEiQ2Y9xv9rLq8VV1UWAwyxq0 eHpjlIJ6b6rbt+ARslaB7drnccOsdK+W/roNj4kfyt+gezjBfojGRdMGQNMFcpnv shuTC+vYurAVIiVA/0IuizgHfwZiXOtVpjVoEWaxg6bBH6HNuYMYzdSa/YrlDkZs n/aBI/Xkvx+Eacu8b1Zwmbzs5EnikUK/2dMqbzXKUZK61eV4hX5c2xrnr1yGWKTs F/juh69Squ7X6VZyKVgJ9RIccVueqwR2EprXWgH3+RMice5kjnXH4zURp0GHALxa DFPfB6fawcH3Ps87kcRFvjgm6FBo0hJ1AxmsW1dY4ACFB9azFa2euW+AARDzHOy2 VRsUdhL9CGwtPjXcZ/9Rhej6fZLGBXKr8uq5QiMuvttp4b6+j9FEfBgD4S6h8csl AT2c2I9LcbWqyUM9P4S7zY/YgOZw88vHRuDH7tEBdIeoiHfrbSBU7EQ9jlAKq/59 f+Htu2Io281c005g7DEeuCYvpzSYnJnAitj5Lmp/kzk2Wn3utY1uIAVszqwf95Ul 81ppn2KlvzUK8g== =7Gj+ -----END PGP SIGNATURE----- Merge tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Thomas Gleixner: "A set of locking fixes and updates: - Untangle the header spaghetti which causes build failures in various situations caused by the lockdep additions to seqcount to validate that the write side critical sections are non-preemptible. - The seqcount associated lock debug addons which were blocked by the above fallout. seqcount writers contrary to seqlock writers must be externally serialized, which usually happens via locking - except for strict per CPU seqcounts. As the lock is not part of the seqcount, lockdep cannot validate that the lock is held. This new debug mechanism adds the concept of associated locks. sequence count has now lock type variants and corresponding initializers which take a pointer to the associated lock used for writer serialization. If lockdep is enabled the pointer is stored and write_seqcount_begin() has a lockdep assertion to validate that the lock is held. Aside of the type and the initializer no other code changes are required at the seqcount usage sites. The rest of the seqcount API is unchanged and determines the type at compile time with the help of _Generic which is possible now that the minimal GCC version has been moved up. Adding this lockdep coverage unearthed a handful of seqcount bugs which have been addressed already independent of this. While generally useful this comes with a Trojan Horse twist: On RT kernels the write side critical section can become preemtible if the writers are serialized by an associated lock, which leads to the well known reader preempts writer livelock. RT prevents this by storing the associated lock pointer independent of lockdep in the seqcount and changing the reader side to block on the lock when a reader detects that a writer is in the write side critical section. - Conversion of seqcount usage sites to associated types and initializers" * tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits) locking/seqlock, headers: Untangle the spaghetti monster locking, arch/ia64: Reduce <asm/smp.h> header dependencies by moving XTP bits into the new <asm/xtp.h> header x86/headers: Remove APIC headers from <asm/smp.h> seqcount: More consistent seqprop names seqcount: Compress SEQCNT_LOCKNAME_ZERO() seqlock: Fold seqcount_LOCKNAME_init() definition seqlock: Fold seqcount_LOCKNAME_t definition seqlock: s/__SEQ_LOCKDEP/__SEQ_LOCK/g hrtimer: Use sequence counter with associated raw spinlock kvm/eventfd: Use sequence counter with associated spinlock userfaultfd: Use sequence counter with associated spinlock NFSv4: Use sequence counter with associated spinlock iocost: Use sequence counter with associated spinlock raid5: Use sequence counter with associated spinlock vfs: Use sequence counter with associated spinlock timekeeping: Use sequence counter with associated raw spinlock xfrm: policy: Use sequence counters with associated lock netfilter: nft_set_rbtree: Use sequence counter with associated rwlock netfilter: conntrack: Use sequence counter with associated spinlock sched: tasks: Use sequence counter with associated spinlock ...
679 lines
16 KiB
C
679 lines
16 KiB
C
/*
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* Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst)
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*
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* Based on bo.c which bears the following copyright notice,
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* but is dual licensed:
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*
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* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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* USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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**************************************************************************/
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/*
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* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
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*/
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#include <linux/dma-resv.h>
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#include <linux/export.h>
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#include <linux/mm.h>
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#include <linux/sched/mm.h>
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#include <linux/mmu_notifier.h>
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/**
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* DOC: Reservation Object Overview
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*
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* The reservation object provides a mechanism to manage shared and
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* exclusive fences associated with a buffer. A reservation object
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* can have attached one exclusive fence (normally associated with
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* write operations) or N shared fences (read operations). The RCU
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* mechanism is used to protect read access to fences from locked
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* write-side updates.
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*/
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DEFINE_WD_CLASS(reservation_ww_class);
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EXPORT_SYMBOL(reservation_ww_class);
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/**
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* dma_resv_list_alloc - allocate fence list
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* @shared_max: number of fences we need space for
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*
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* Allocate a new dma_resv_list and make sure to correctly initialize
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* shared_max.
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*/
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static struct dma_resv_list *dma_resv_list_alloc(unsigned int shared_max)
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{
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struct dma_resv_list *list;
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list = kmalloc(offsetof(typeof(*list), shared[shared_max]), GFP_KERNEL);
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if (!list)
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return NULL;
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list->shared_max = (ksize(list) - offsetof(typeof(*list), shared)) /
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sizeof(*list->shared);
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return list;
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}
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/**
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* dma_resv_list_free - free fence list
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* @list: list to free
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*
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* Free a dma_resv_list and make sure to drop all references.
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*/
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static void dma_resv_list_free(struct dma_resv_list *list)
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{
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unsigned int i;
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if (!list)
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return;
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for (i = 0; i < list->shared_count; ++i)
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dma_fence_put(rcu_dereference_protected(list->shared[i], true));
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kfree_rcu(list, rcu);
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}
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#if IS_ENABLED(CONFIG_LOCKDEP)
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static int __init dma_resv_lockdep(void)
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{
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struct mm_struct *mm = mm_alloc();
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struct ww_acquire_ctx ctx;
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struct dma_resv obj;
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int ret;
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if (!mm)
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return -ENOMEM;
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dma_resv_init(&obj);
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mmap_read_lock(mm);
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ww_acquire_init(&ctx, &reservation_ww_class);
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ret = dma_resv_lock(&obj, &ctx);
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if (ret == -EDEADLK)
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dma_resv_lock_slow(&obj, &ctx);
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fs_reclaim_acquire(GFP_KERNEL);
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#ifdef CONFIG_MMU_NOTIFIER
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lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
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__dma_fence_might_wait();
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lock_map_release(&__mmu_notifier_invalidate_range_start_map);
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#else
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__dma_fence_might_wait();
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#endif
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fs_reclaim_release(GFP_KERNEL);
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ww_mutex_unlock(&obj.lock);
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ww_acquire_fini(&ctx);
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mmap_read_unlock(mm);
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mmput(mm);
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return 0;
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}
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subsys_initcall(dma_resv_lockdep);
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#endif
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/**
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* dma_resv_init - initialize a reservation object
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* @obj: the reservation object
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*/
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void dma_resv_init(struct dma_resv *obj)
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{
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ww_mutex_init(&obj->lock, &reservation_ww_class);
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seqcount_ww_mutex_init(&obj->seq, &obj->lock);
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RCU_INIT_POINTER(obj->fence, NULL);
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RCU_INIT_POINTER(obj->fence_excl, NULL);
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}
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EXPORT_SYMBOL(dma_resv_init);
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/**
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* dma_resv_fini - destroys a reservation object
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* @obj: the reservation object
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*/
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void dma_resv_fini(struct dma_resv *obj)
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{
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struct dma_resv_list *fobj;
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struct dma_fence *excl;
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/*
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* This object should be dead and all references must have
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* been released to it, so no need to be protected with rcu.
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*/
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excl = rcu_dereference_protected(obj->fence_excl, 1);
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if (excl)
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dma_fence_put(excl);
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fobj = rcu_dereference_protected(obj->fence, 1);
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dma_resv_list_free(fobj);
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ww_mutex_destroy(&obj->lock);
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}
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EXPORT_SYMBOL(dma_resv_fini);
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/**
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* dma_resv_reserve_shared - Reserve space to add shared fences to
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* a dma_resv.
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* @obj: reservation object
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* @num_fences: number of fences we want to add
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*
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* Should be called before dma_resv_add_shared_fence(). Must
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* be called with obj->lock held.
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*
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* RETURNS
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* Zero for success, or -errno
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*/
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int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences)
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{
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struct dma_resv_list *old, *new;
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unsigned int i, j, k, max;
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dma_resv_assert_held(obj);
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old = dma_resv_get_list(obj);
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if (old && old->shared_max) {
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if ((old->shared_count + num_fences) <= old->shared_max)
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return 0;
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else
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max = max(old->shared_count + num_fences,
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old->shared_max * 2);
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} else {
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max = 4;
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}
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new = dma_resv_list_alloc(max);
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if (!new)
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return -ENOMEM;
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/*
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* no need to bump fence refcounts, rcu_read access
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* requires the use of kref_get_unless_zero, and the
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* references from the old struct are carried over to
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* the new.
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*/
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for (i = 0, j = 0, k = max; i < (old ? old->shared_count : 0); ++i) {
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struct dma_fence *fence;
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fence = rcu_dereference_protected(old->shared[i],
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dma_resv_held(obj));
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if (dma_fence_is_signaled(fence))
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RCU_INIT_POINTER(new->shared[--k], fence);
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else
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RCU_INIT_POINTER(new->shared[j++], fence);
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}
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new->shared_count = j;
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/*
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* We are not changing the effective set of fences here so can
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* merely update the pointer to the new array; both existing
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* readers and new readers will see exactly the same set of
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* active (unsignaled) shared fences. Individual fences and the
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* old array are protected by RCU and so will not vanish under
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* the gaze of the rcu_read_lock() readers.
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*/
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rcu_assign_pointer(obj->fence, new);
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if (!old)
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return 0;
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/* Drop the references to the signaled fences */
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for (i = k; i < max; ++i) {
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struct dma_fence *fence;
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fence = rcu_dereference_protected(new->shared[i],
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dma_resv_held(obj));
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dma_fence_put(fence);
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}
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kfree_rcu(old, rcu);
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return 0;
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}
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EXPORT_SYMBOL(dma_resv_reserve_shared);
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/**
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* dma_resv_add_shared_fence - Add a fence to a shared slot
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* @obj: the reservation object
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* @fence: the shared fence to add
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*
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* Add a fence to a shared slot, obj->lock must be held, and
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* dma_resv_reserve_shared() has been called.
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*/
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void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence)
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{
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struct dma_resv_list *fobj;
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struct dma_fence *old;
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unsigned int i, count;
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dma_fence_get(fence);
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dma_resv_assert_held(obj);
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fobj = dma_resv_get_list(obj);
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count = fobj->shared_count;
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write_seqcount_begin(&obj->seq);
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for (i = 0; i < count; ++i) {
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old = rcu_dereference_protected(fobj->shared[i],
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dma_resv_held(obj));
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if (old->context == fence->context ||
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dma_fence_is_signaled(old))
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goto replace;
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}
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BUG_ON(fobj->shared_count >= fobj->shared_max);
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old = NULL;
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count++;
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replace:
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RCU_INIT_POINTER(fobj->shared[i], fence);
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/* pointer update must be visible before we extend the shared_count */
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smp_store_mb(fobj->shared_count, count);
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write_seqcount_end(&obj->seq);
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dma_fence_put(old);
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}
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EXPORT_SYMBOL(dma_resv_add_shared_fence);
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/**
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* dma_resv_add_excl_fence - Add an exclusive fence.
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* @obj: the reservation object
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* @fence: the shared fence to add
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*
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* Add a fence to the exclusive slot. The obj->lock must be held.
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*/
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void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence)
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{
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struct dma_fence *old_fence = dma_resv_get_excl(obj);
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struct dma_resv_list *old;
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u32 i = 0;
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dma_resv_assert_held(obj);
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old = dma_resv_get_list(obj);
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if (old)
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i = old->shared_count;
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if (fence)
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dma_fence_get(fence);
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write_seqcount_begin(&obj->seq);
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/* write_seqcount_begin provides the necessary memory barrier */
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RCU_INIT_POINTER(obj->fence_excl, fence);
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if (old)
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old->shared_count = 0;
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write_seqcount_end(&obj->seq);
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/* inplace update, no shared fences */
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while (i--)
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dma_fence_put(rcu_dereference_protected(old->shared[i],
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dma_resv_held(obj)));
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dma_fence_put(old_fence);
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}
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EXPORT_SYMBOL(dma_resv_add_excl_fence);
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/**
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* dma_resv_copy_fences - Copy all fences from src to dst.
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* @dst: the destination reservation object
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* @src: the source reservation object
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*
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* Copy all fences from src to dst. dst-lock must be held.
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*/
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int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)
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{
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struct dma_resv_list *src_list, *dst_list;
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struct dma_fence *old, *new;
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unsigned i;
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dma_resv_assert_held(dst);
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rcu_read_lock();
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src_list = rcu_dereference(src->fence);
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retry:
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if (src_list) {
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unsigned shared_count = src_list->shared_count;
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rcu_read_unlock();
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dst_list = dma_resv_list_alloc(shared_count);
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if (!dst_list)
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return -ENOMEM;
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rcu_read_lock();
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src_list = rcu_dereference(src->fence);
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if (!src_list || src_list->shared_count > shared_count) {
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kfree(dst_list);
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goto retry;
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}
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dst_list->shared_count = 0;
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for (i = 0; i < src_list->shared_count; ++i) {
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struct dma_fence *fence;
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fence = rcu_dereference(src_list->shared[i]);
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if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
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&fence->flags))
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continue;
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if (!dma_fence_get_rcu(fence)) {
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dma_resv_list_free(dst_list);
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src_list = rcu_dereference(src->fence);
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goto retry;
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}
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if (dma_fence_is_signaled(fence)) {
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dma_fence_put(fence);
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continue;
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}
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rcu_assign_pointer(dst_list->shared[dst_list->shared_count++], fence);
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}
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} else {
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dst_list = NULL;
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}
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new = dma_fence_get_rcu_safe(&src->fence_excl);
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rcu_read_unlock();
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src_list = dma_resv_get_list(dst);
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old = dma_resv_get_excl(dst);
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write_seqcount_begin(&dst->seq);
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/* write_seqcount_begin provides the necessary memory barrier */
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RCU_INIT_POINTER(dst->fence_excl, new);
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RCU_INIT_POINTER(dst->fence, dst_list);
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|
write_seqcount_end(&dst->seq);
|
|
|
|
dma_resv_list_free(src_list);
|
|
dma_fence_put(old);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(dma_resv_copy_fences);
|
|
|
|
/**
|
|
* dma_resv_get_fences_rcu - Get an object's shared and exclusive
|
|
* fences without update side lock held
|
|
* @obj: the reservation object
|
|
* @pfence_excl: the returned exclusive fence (or NULL)
|
|
* @pshared_count: the number of shared fences returned
|
|
* @pshared: the array of shared fence ptrs returned (array is krealloc'd to
|
|
* the required size, and must be freed by caller)
|
|
*
|
|
* Retrieve all fences from the reservation object. If the pointer for the
|
|
* exclusive fence is not specified the fence is put into the array of the
|
|
* shared fences as well. Returns either zero or -ENOMEM.
|
|
*/
|
|
int dma_resv_get_fences_rcu(struct dma_resv *obj,
|
|
struct dma_fence **pfence_excl,
|
|
unsigned *pshared_count,
|
|
struct dma_fence ***pshared)
|
|
{
|
|
struct dma_fence **shared = NULL;
|
|
struct dma_fence *fence_excl;
|
|
unsigned int shared_count;
|
|
int ret = 1;
|
|
|
|
do {
|
|
struct dma_resv_list *fobj;
|
|
unsigned int i, seq;
|
|
size_t sz = 0;
|
|
|
|
shared_count = i = 0;
|
|
|
|
rcu_read_lock();
|
|
seq = read_seqcount_begin(&obj->seq);
|
|
|
|
fence_excl = rcu_dereference(obj->fence_excl);
|
|
if (fence_excl && !dma_fence_get_rcu(fence_excl))
|
|
goto unlock;
|
|
|
|
fobj = rcu_dereference(obj->fence);
|
|
if (fobj)
|
|
sz += sizeof(*shared) * fobj->shared_max;
|
|
|
|
if (!pfence_excl && fence_excl)
|
|
sz += sizeof(*shared);
|
|
|
|
if (sz) {
|
|
struct dma_fence **nshared;
|
|
|
|
nshared = krealloc(shared, sz,
|
|
GFP_NOWAIT | __GFP_NOWARN);
|
|
if (!nshared) {
|
|
rcu_read_unlock();
|
|
|
|
dma_fence_put(fence_excl);
|
|
fence_excl = NULL;
|
|
|
|
nshared = krealloc(shared, sz, GFP_KERNEL);
|
|
if (nshared) {
|
|
shared = nshared;
|
|
continue;
|
|
}
|
|
|
|
ret = -ENOMEM;
|
|
break;
|
|
}
|
|
shared = nshared;
|
|
shared_count = fobj ? fobj->shared_count : 0;
|
|
for (i = 0; i < shared_count; ++i) {
|
|
shared[i] = rcu_dereference(fobj->shared[i]);
|
|
if (!dma_fence_get_rcu(shared[i]))
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (i != shared_count || read_seqcount_retry(&obj->seq, seq)) {
|
|
while (i--)
|
|
dma_fence_put(shared[i]);
|
|
dma_fence_put(fence_excl);
|
|
goto unlock;
|
|
}
|
|
|
|
ret = 0;
|
|
unlock:
|
|
rcu_read_unlock();
|
|
} while (ret);
|
|
|
|
if (pfence_excl)
|
|
*pfence_excl = fence_excl;
|
|
else if (fence_excl)
|
|
shared[shared_count++] = fence_excl;
|
|
|
|
if (!shared_count) {
|
|
kfree(shared);
|
|
shared = NULL;
|
|
}
|
|
|
|
*pshared_count = shared_count;
|
|
*pshared = shared;
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dma_resv_get_fences_rcu);
|
|
|
|
/**
|
|
* dma_resv_wait_timeout_rcu - Wait on reservation's objects
|
|
* shared and/or exclusive fences.
|
|
* @obj: the reservation object
|
|
* @wait_all: if true, wait on all fences, else wait on just exclusive fence
|
|
* @intr: if true, do interruptible wait
|
|
* @timeout: timeout value in jiffies or zero to return immediately
|
|
*
|
|
* RETURNS
|
|
* Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
|
|
* greater than zer on success.
|
|
*/
|
|
long dma_resv_wait_timeout_rcu(struct dma_resv *obj,
|
|
bool wait_all, bool intr,
|
|
unsigned long timeout)
|
|
{
|
|
struct dma_fence *fence;
|
|
unsigned seq, shared_count;
|
|
long ret = timeout ? timeout : 1;
|
|
int i;
|
|
|
|
retry:
|
|
shared_count = 0;
|
|
seq = read_seqcount_begin(&obj->seq);
|
|
rcu_read_lock();
|
|
i = -1;
|
|
|
|
fence = rcu_dereference(obj->fence_excl);
|
|
if (fence && !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
|
|
if (!dma_fence_get_rcu(fence))
|
|
goto unlock_retry;
|
|
|
|
if (dma_fence_is_signaled(fence)) {
|
|
dma_fence_put(fence);
|
|
fence = NULL;
|
|
}
|
|
|
|
} else {
|
|
fence = NULL;
|
|
}
|
|
|
|
if (wait_all) {
|
|
struct dma_resv_list *fobj = rcu_dereference(obj->fence);
|
|
|
|
if (fobj)
|
|
shared_count = fobj->shared_count;
|
|
|
|
for (i = 0; !fence && i < shared_count; ++i) {
|
|
struct dma_fence *lfence = rcu_dereference(fobj->shared[i]);
|
|
|
|
if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
|
|
&lfence->flags))
|
|
continue;
|
|
|
|
if (!dma_fence_get_rcu(lfence))
|
|
goto unlock_retry;
|
|
|
|
if (dma_fence_is_signaled(lfence)) {
|
|
dma_fence_put(lfence);
|
|
continue;
|
|
}
|
|
|
|
fence = lfence;
|
|
break;
|
|
}
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
if (fence) {
|
|
if (read_seqcount_retry(&obj->seq, seq)) {
|
|
dma_fence_put(fence);
|
|
goto retry;
|
|
}
|
|
|
|
ret = dma_fence_wait_timeout(fence, intr, ret);
|
|
dma_fence_put(fence);
|
|
if (ret > 0 && wait_all && (i + 1 < shared_count))
|
|
goto retry;
|
|
}
|
|
return ret;
|
|
|
|
unlock_retry:
|
|
rcu_read_unlock();
|
|
goto retry;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dma_resv_wait_timeout_rcu);
|
|
|
|
|
|
static inline int dma_resv_test_signaled_single(struct dma_fence *passed_fence)
|
|
{
|
|
struct dma_fence *fence, *lfence = passed_fence;
|
|
int ret = 1;
|
|
|
|
if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &lfence->flags)) {
|
|
fence = dma_fence_get_rcu(lfence);
|
|
if (!fence)
|
|
return -1;
|
|
|
|
ret = !!dma_fence_is_signaled(fence);
|
|
dma_fence_put(fence);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* dma_resv_test_signaled_rcu - Test if a reservation object's
|
|
* fences have been signaled.
|
|
* @obj: the reservation object
|
|
* @test_all: if true, test all fences, otherwise only test the exclusive
|
|
* fence
|
|
*
|
|
* RETURNS
|
|
* true if all fences signaled, else false
|
|
*/
|
|
bool dma_resv_test_signaled_rcu(struct dma_resv *obj, bool test_all)
|
|
{
|
|
unsigned seq, shared_count;
|
|
int ret;
|
|
|
|
rcu_read_lock();
|
|
retry:
|
|
ret = true;
|
|
shared_count = 0;
|
|
seq = read_seqcount_begin(&obj->seq);
|
|
|
|
if (test_all) {
|
|
unsigned i;
|
|
|
|
struct dma_resv_list *fobj = rcu_dereference(obj->fence);
|
|
|
|
if (fobj)
|
|
shared_count = fobj->shared_count;
|
|
|
|
for (i = 0; i < shared_count; ++i) {
|
|
struct dma_fence *fence = rcu_dereference(fobj->shared[i]);
|
|
|
|
ret = dma_resv_test_signaled_single(fence);
|
|
if (ret < 0)
|
|
goto retry;
|
|
else if (!ret)
|
|
break;
|
|
}
|
|
|
|
if (read_seqcount_retry(&obj->seq, seq))
|
|
goto retry;
|
|
}
|
|
|
|
if (!shared_count) {
|
|
struct dma_fence *fence_excl = rcu_dereference(obj->fence_excl);
|
|
|
|
if (fence_excl) {
|
|
ret = dma_resv_test_signaled_single(fence_excl);
|
|
if (ret < 0)
|
|
goto retry;
|
|
|
|
if (read_seqcount_retry(&obj->seq, seq))
|
|
goto retry;
|
|
}
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dma_resv_test_signaled_rcu);
|