cregit-Linux how code gets into the kernel

Release 4.17 drivers/gpu/drm/i915/i915_gem_batch_pool.c

/*
 * Copyright © 2014 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

#include "i915_drv.h"
#include "i915_gem_batch_pool.h"

/**
 * DOC: batch pool
 *
 * In order to submit batch buffers as 'secure', the software command parser
 * must ensure that a batch buffer cannot be modified after parsing. It does
 * this by copying the user provided batch buffer contents to a kernel owned
 * buffer from which the hardware will actually execute, and by carefully
 * managing the address space bindings for such buffers.
 *
 * The batch pool framework provides a mechanism for the driver to manage a
 * set of scratch buffers to use for this purpose. The framework can be
 * extended to support other uses cases should they arise.
 */

/**
 * i915_gem_batch_pool_init() - initialize a batch buffer pool
 * @engine: the associated request submission engine
 * @pool: the batch buffer pool
 */

void i915_gem_batch_pool_init(struct intel_engine_cs *engine, struct i915_gem_batch_pool *pool) { int n; pool->engine = engine; for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) INIT_LIST_HEAD(&pool->cache_list[n]); }

Contributors

PersonTokensPropCommitsCommitProp
Chris Wilson2852.83%266.67%
Brad Volkin2547.17%133.33%
Total53100.00%3100.00%

/** * i915_gem_batch_pool_fini() - clean up a batch buffer pool * @pool: the pool to clean up * * Note: Callers must hold the struct_mutex. */
void i915_gem_batch_pool_fini(struct i915_gem_batch_pool *pool) { int n; lockdep_assert_held(&pool->engine->i915->drm.struct_mutex); for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) { struct drm_i915_gem_object *obj, *next; list_for_each_entry_safe(obj, next, &pool->cache_list[n], batch_pool_link) __i915_gem_object_release_unless_active(obj); INIT_LIST_HEAD(&pool->cache_list[n]); } }

Contributors

PersonTokensPropCommitsCommitProp
Chris Wilson4758.02%480.00%
Brad Volkin3441.98%120.00%
Total81100.00%5100.00%

/** * i915_gem_batch_pool_get() - allocate a buffer from the pool * @pool: the batch buffer pool * @size: the minimum desired size of the returned buffer * * Returns an inactive buffer from @pool with at least @size bytes, * with the pages pinned. The caller must i915_gem_object_unpin_pages() * on the returned object. * * Note: Callers must hold the struct_mutex * * Return: the buffer object or an error pointer */
struct drm_i915_gem_object * i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool, size_t size) { struct drm_i915_gem_object *obj; struct list_head *list; int n, ret; lockdep_assert_held(&pool->engine->i915->drm.struct_mutex); /* Compute a power-of-two bucket, but throw everything greater than * 16KiB into the same bucket: i.e. the the buckets hold objects of * (1 page, 2 pages, 4 pages, 8+ pages). */ n = fls(size >> PAGE_SHIFT) - 1; if (n >= ARRAY_SIZE(pool->cache_list)) n = ARRAY_SIZE(pool->cache_list) - 1; list = &pool->cache_list[n]; list_for_each_entry(obj, list, batch_pool_link) { /* The batches are strictly LRU ordered */ if (i915_gem_object_is_active(obj)) { struct reservation_object *resv = obj->resv; if (!reservation_object_test_signaled_rcu(resv, true)) break; i915_retire_requests(pool->engine->i915); GEM_BUG_ON(i915_gem_object_is_active(obj)); /* * The object is now idle, clear the array of shared * fences before we add a new request. Although, we * remain on the same engine, we may be on a different * timeline and so may continually grow the array, * trapping a reference to all the old fences, rather * than replace the existing fence. */ if (rcu_access_pointer(resv->fence)) { reservation_object_lock(resv, NULL); reservation_object_add_excl_fence(resv, NULL); reservation_object_unlock(resv); } } GEM_BUG_ON(!reservation_object_test_signaled_rcu(obj->resv, true)); if (obj->base.size >= size) goto found; } obj = i915_gem_object_create_internal(pool->engine->i915, size); if (IS_ERR(obj)) return obj; found: ret = i915_gem_object_pin_pages(obj); if (ret) return ERR_PTR(ret); list_move_tail(&obj->batch_pool_link, list); return obj; }

Contributors

PersonTokensPropCommitsCommitProp
Chris Wilson18772.76%1191.67%
Brad Volkin7027.24%18.33%
Total257100.00%12100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Chris Wilson26766.42%1493.33%
Brad Volkin13533.58%16.67%
Total402100.00%15100.00%
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