From patchwork Sat Jul 25 03:26:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Stultz X-Patchwork-Id: 11684767 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1640F13B4 for ; Sat, 25 Jul 2020 03:26:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC15F20719 for ; Sat, 25 Jul 2020 03:26:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="RbNTN2vP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726760AbgGYD0i (ORCPT ); Fri, 24 Jul 2020 23:26:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726572AbgGYD0i (ORCPT ); Fri, 24 Jul 2020 23:26:38 -0400 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF41EC0619D3 for ; Fri, 24 Jul 2020 20:26:37 -0700 (PDT) Received: by mail-pf1-x441.google.com with SMTP id u185so6310978pfu.1 for ; Fri, 24 Jul 2020 20:26:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=H0jwgkKJw1F2QGrxp3XRsBO4Zv0vbxAb7H7LFDlABiQ=; b=RbNTN2vPJ+dA/LwMFiC3sJgHNi9P7iDpEf0QPN9vRRqQ7v6rh8ugXQpi5Vouhpb/+x E/SZz2L0MCrCHEVHr9cQu4Fa+J9Oq6lk738yyuyDRw+2Ej5YQOGNQjVEs6rpQ38YxvVY mrkXyY/dpROjus1mzoaCe3ZvJaPBbZsCVRiB3LkavibRHIGwVH5CbMFDNohLUpHSyO1R Hf0jM7DvjDSq3Id5l1M0ElsmQ1zPlI5eziR8fpmSC7io0yxpn4ckZiTj+RBX2EA7SUhy pmLxYj5HhfjFkeeE+7fkuSm24xWP8b4xfqAthKMGLZI9OKgeJEKSaT1uD/uQzBOK3UST A6Tw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=H0jwgkKJw1F2QGrxp3XRsBO4Zv0vbxAb7H7LFDlABiQ=; b=RxX123mbV+8vcz072Kg8Fvy4L1HnsXfmxUFHH8fpfbSrOdzlOMDMOHmjt315RZoO8x e4TuOpUor+GivyFm5Pkh3zG9fGgvPeEMQ50rFtg2DhkC0Z26OlHZ0cOaPG2MEQ5nUULm I4XZ0gj+o8VcM/EdF8okMZV2kk26yziyeaoTOmpPWq6o9gJXQbLUnXZLpzIUWPvl+RFV 5TyYeQPUJGOyXVoU7woz7T+DSAlGgyx5vlc62Rfi8Lv37vwuyuZrAjU+N9UynBRHZfEi vsIbQ5CzSRduaEmJ8VlPEhDICskxkw4mOK/M58M0rtpZaQl7OCO0pP7OzZByEJ10dxq8 xUSw== X-Gm-Message-State: AOAM5326/s+IDWn2o2jA06sodofzST02spKkp0S1Mt259+PZWbODO9YS HdLA9hU2BU6o3NycJ0lea/U86g== X-Google-Smtp-Source: ABdhPJye4Zi1p+g7i5EeVNtB5XOqoG/SM8okB5VAhbaF1GX8NRKfTkCuaLkqofWvksTtGS/kYQYgww== X-Received: by 2002:a63:fe42:: with SMTP id x2mr11177808pgj.207.1595647597349; Fri, 24 Jul 2020 20:26:37 -0700 (PDT) Received: from localhost.localdomain ([2601:1c2:680:1319:692:26ff:feda:3a81]) by smtp.gmail.com with ESMTPSA id 204sm7754074pfx.3.2020.07.24.20.26.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Jul 2020 20:26:36 -0700 (PDT) From: John Stultz To: lkml Cc: John Stultz , Sumit Semwal , "Andrew F . Davis" , Benjamin Gaignard , Liam Mark , Laura Abbott , Brian Starkey , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: [RFC][PATCH] dma-heap: Add proper kref handling on dma-buf heaps Date: Sat, 25 Jul 2020 03:26:33 +0000 Message-Id: <20200725032633.125006-1-john.stultz@linaro.org> X-Mailer: git-send-email 2.17.1 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Add proper refcounting on the dma_heap structure. While existing heaps are built-in, we may eventually have heaps loaded from modules, and we'll need to be able to properly handle the references to the heaps Cc: Sumit Semwal Cc: Andrew F. Davis Cc: Benjamin Gaignard Cc: Liam Mark Cc: Laura Abbott Cc: Brian Starkey Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Signed-off-by: John Stultz --- drivers/dma-buf/dma-heap.c | 31 +++++++++++++++++++++++++++---- include/linux/dma-heap.h | 6 ++++++ 2 files changed, 33 insertions(+), 4 deletions(-) diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index afd22c9dbdcf..90c3720acc1c 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -40,6 +40,8 @@ struct dma_heap { dev_t heap_devt; struct list_head list; struct cdev heap_cdev; + int minor; + struct kref refcount; }; static LIST_HEAD(heap_list); @@ -190,11 +192,31 @@ void *dma_heap_get_drvdata(struct dma_heap *heap) return heap->priv; } +static void dma_heap_release(struct kref *ref) +{ + struct dma_heap *heap = container_of(ref, struct dma_heap, refcount); + + /* Remove heap from the list */ + mutex_lock(&heap_list_lock); + list_del(&heap->list); + mutex_unlock(&heap_list_lock); + + device_destroy(dma_heap_class, heap->heap_devt); + cdev_del(&heap->heap_cdev); + xa_erase(&dma_heap_minors, heap->minor); + + kfree(heap); +} + +void dma_heap_put(struct dma_heap *h) +{ + kref_put(&h->refcount, dma_heap_release); +} + struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) { struct dma_heap *heap, *h, *err_ret; struct device *dev_ret; - unsigned int minor; int ret; if (!exp_info->name || !strcmp(exp_info->name, "")) { @@ -223,12 +245,13 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) if (!heap) return ERR_PTR(-ENOMEM); + kref_init(&heap->refcount); heap->name = exp_info->name; heap->ops = exp_info->ops; heap->priv = exp_info->priv; /* Find unused minor number */ - ret = xa_alloc(&dma_heap_minors, &minor, heap, + ret = xa_alloc(&dma_heap_minors, &heap->minor, heap, XA_LIMIT(0, NUM_HEAP_MINORS - 1), GFP_KERNEL); if (ret < 0) { pr_err("dma_heap: Unable to get minor number for heap\n"); @@ -237,7 +260,7 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) } /* Create device */ - heap->heap_devt = MKDEV(MAJOR(dma_heap_devt), minor); + heap->heap_devt = MKDEV(MAJOR(dma_heap_devt), heap->minor); cdev_init(&heap->heap_cdev, &dma_heap_fops); ret = cdev_add(&heap->heap_cdev, heap->heap_devt, 1); @@ -267,7 +290,7 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) err2: cdev_del(&heap->heap_cdev); err1: - xa_erase(&dma_heap_minors, minor); + xa_erase(&dma_heap_minors, heap->minor); err0: kfree(heap); return err_ret; diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h index 454e354d1ffb..c1572f29cfac 100644 --- a/include/linux/dma-heap.h +++ b/include/linux/dma-heap.h @@ -56,4 +56,10 @@ void *dma_heap_get_drvdata(struct dma_heap *heap); */ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info); +/** + * dma_heap_put - drops a reference to a dmabuf heaps, potentially freeing it + * @heap: heap pointer + */ +void dma_heap_put(struct dma_heap *heap); + #endif /* _DMA_HEAPS_H */