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[134.134.139.74]) by smtp.gmail.com with ESMTPSA id l19sm117708pjt.16.2021.03.17.15.19.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Mar 2021 15:19:49 -0700 (PDT) From: Jason Ekstrand To: dri-devel@lists.freedesktop.org Subject: [PATCH 2/3] dma-buf: add dma_resv_get_singleton_rcu (v3) Date: Wed, 17 Mar 2021 17:19:39 -0500 Message-Id: <20210317221940.2146688-3-jason@jlekstrand.net> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210317221940.2146688-1-jason@jlekstrand.net> References: <20210316045322.2020294-1-jason@jlekstrand.net> <20210317221940.2146688-1-jason@jlekstrand.net> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jason Ekstrand Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Add a helper function to get a single fence representing all fences in a dma_resv object. This fence is either the only one in the object or all not signaled fences of the object in a flatted out dma_fence_array. v2 (Jason Ekstrand): - Take reference of fences both for creating the dma_fence_array and in the case where we return one fence. - Handle the case where dma_resv_get_list() returns NULL v3 (Jason Ekstrand): - Add an _rcu suffix because it is read-only - Rewrite to use dma_resv_get_fences_rcu so it's RCU-safe - Add an EXPORT_SYMBOL_GPL declaration - Re-author the patch to Jason since very little is left of Christian König's original patch Signed-off-by: Jason Ekstrand --- drivers/dma-buf/dma-resv.c | 104 +++++++++++++++++++++++++++++++++++++ include/linux/dma-resv.h | 2 + 2 files changed, 106 insertions(+) diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 6ddbeb5dfbf65..5dd4c38bd9cb4 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -33,6 +33,8 @@ */ #include +#include +#include #include #include #include @@ -49,6 +51,19 @@ * write-side updates. */ +/** + * dma_fence_deep_dive_for_each - deep dive into the fence containers + * @fence: resulting fence + * @chain: variable for a dma_fence_chain + * @index: index into a dma_fence_array + * @head: starting point + * + * Helper to deep dive into the fence containers for flattening them. + */ +#define dma_fence_deep_dive_for_each(fence, chain, index, head) \ + dma_fence_chain_for_each(chain, head) \ + dma_fence_array_for_each(fence, index, chain) + DEFINE_WD_CLASS(reservation_ww_class); EXPORT_SYMBOL(reservation_ww_class); @@ -517,6 +532,95 @@ int dma_resv_get_fences_rcu(struct dma_resv *obj, } EXPORT_SYMBOL_GPL(dma_resv_get_fences_rcu); +/** + * dma_resv_get_singleton - get a single fence for the dma_resv object + * @obj: the reservation object + * @extra: extra fence to add to the resulting array + * @result: resulting dma_fence + * + * Get a single fence representing all unsignaled fences in the dma_resv object + * plus the given extra fence. If we got only one fence return a new + * reference to that, otherwise return a dma_fence_array object. + * + * RETURNS + * Returns -NOMEM if allocations fail, zero otherwise. + */ +int dma_resv_get_singleton_rcu(struct dma_resv *obj, struct dma_fence **result) +{ + struct dma_fence **resv_fences, *fence, *chain, **fences; + struct dma_fence_array *array; + unsigned int num_resv_fences, num_fences; + unsigned int ret, i, j; + + ret = dma_resv_get_fences_rcu(obj, NULL, &num_resv_fences, &resv_fences); + if (ret) + return ret; + + num_fences = 0; + *result = NULL; + + if (num_resv_fences == 0) + return 0; + + for (i = 0; i < num_resv_fences; ++i) { + dma_fence_deep_dive_for_each(fence, chain, j, resv_fences[i]) { + if (dma_fence_is_signaled(fence)) + continue; + + *result = fence; + ++num_fences; + } + } + + if (num_fences <= 1) { + *result = dma_fence_get(*result); + goto put_resv_fences; + } + + fences = kmalloc_array(num_fences, sizeof(struct dma_fence*), + GFP_KERNEL); + if (!fences) { + *result = NULL; + ret = -ENOMEM; + goto put_resv_fences; + } + + num_fences = 0; + for (i = 0; i < num_resv_fences; ++i) { + dma_fence_deep_dive_for_each(fence, chain, j, resv_fences[i]) { + if (!dma_fence_is_signaled(fence)) + fences[num_fences++] = dma_fence_get(fence); + } + } + + if (num_fences <= 1) { + *result = num_fences ? fences[0] : NULL; + kfree(fences); + goto put_resv_fences; + } + + array = dma_fence_array_create(num_fences, fences, + dma_fence_context_alloc(1), + 1, false); + if (array) { + *result = &array->base; + } else { + *result = NULL; + while (num_fences--) + dma_fence_put(fences[num_fences]); + kfree(fences); + ret = -ENOMEM; + } + +put_resv_fences: + while (num_resv_fences--) + dma_fence_put(resv_fences[num_resv_fences]); + kfree(resv_fences); + + return ret; +} +EXPORT_SYMBOL_GPL(dma_resv_get_singleton_rcu); + /** * dma_resv_wait_timeout_rcu - Wait on reservation's objects * shared and/or exclusive fences. diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index d44a77e8a7e34..5f82894fed0b9 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -285,6 +285,8 @@ int dma_resv_get_fences_rcu(struct dma_resv *obj, int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src); +int dma_resv_get_singleton_rcu(struct dma_resv *obj, struct dma_fence **result); + long dma_resv_wait_timeout_rcu(struct dma_resv *obj, bool wait_all, bool intr, unsigned long timeout);