From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B160C31E45 for ; Thu, 13 Jun 2019 17:15:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EC04E2053B for ; Thu, 13 Jun 2019 17:15:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="UUaKcHV0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393677AbfFMRPf (ORCPT ); Thu, 13 Jun 2019 13:15:35 -0400 Received: from mail-qk1-f202.google.com ([209.85.222.202]:42988 "EHLO mail-qk1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728765AbfFLVsa (ORCPT ); Wed, 12 Jun 2019 17:48:30 -0400 Received: by mail-qk1-f202.google.com with SMTP id l16so14878830qkk.9 for ; Wed, 12 Jun 2019 14:48:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=x5JY2SGL+SYSEHfOtRFLuisOxAVpr293xNU/5K/Orhw=; b=UUaKcHV0d/LC9+lq01zBflV+hCjVCVqmBE3jKTCQMDYMhgFQy+hqBR570RqhY5BnO5 2IdZs3XxNUJtkmViwwhRiHpFp/XG+c+QSQrYmi51xctcNWKz5S4Txw2nmLK71Ro1G0EN OaJ166g8QaVYhoP5Tsycy2cjIRDzgW4ij0dL3tEm4k9n+z0cxZ/9Hady/0qGiVWaVUTd Y8An01p9TIj02KL22FwkySr1gVzpRzokRLgL8in5Bdgod1xbgpPxT104Qjd9D7R+5LZ0 /HmuO037rHLdWnkRlHMbQzG5jNpPL7ICo6CSqH65uQqvTLy7hmDpNxpPnOT3mViN9Rp3 B/9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=x5JY2SGL+SYSEHfOtRFLuisOxAVpr293xNU/5K/Orhw=; b=lRI3HRTkMG7q0fj777AKbOO7DqLX7ydt9Jp4KtmjJKFGPHUQJ7xUnGy4sFi9l1cq22 XV5jTKEAf42QGeJueAoweiKS8aQX2IIUfFL7MxEFcVrLamO5/B8EwRasmWJTW5zQ2qsv otp/MH1RCMH6jiZMrGJjpGdwsi65IS+RqH/o0HoqBNj+iYMmUXAY3YYB2SdS3w7iZXal ZBDiMt49SVYRKQqTm0oxCt9bdrfzg2c9dpkMDje3w8WxZfIHFITJUZi44GjGtslb8DdE 0f4fAK1Oj+QFwD1wPUiAp8w0aAFCrRWXjRllNjuURxzIjDPePmkjRQ3OzBMiIQu6bwbx aSEw== X-Gm-Message-State: APjAAAUBif6uxz6+mIYpQ8FbEfZHCUlhDWre8WDWVCS/YoT7rMWD6IY7 bJ8QT4CqQeF+vzqGHyw324SKI8JTz6yaWufuvmqbTEWu/ZfoZJ+R+Uu7D1sUO7Qow10doTZYFzS mbxmpzA+zpuWfhyZLWo+d5s9dztsudRiotPyVRKpY0GQO+VQWFF2q06npInGR+u86y/8= X-Google-Smtp-Source: APXvYqwr+6rEdJFDESoMYNaauRo/3rWccerZ0C2ktPwJ7mVmdx1JRJZW8i/Lp6aMelPjce+Ea2P6/S8itQ== X-Received: by 2002:ac8:7c7:: with SMTP id m7mr68019754qth.28.1560376108860; Wed, 12 Jun 2019 14:48:28 -0700 (PDT) Date: Wed, 12 Jun 2019 14:48:21 -0700 In-Reply-To: <20190612214823.251491-1-fengc@google.com> Message-Id: <20190612214823.251491-2-fengc@google.com> Mime-Version: 1.0 References: <20190612214823.251491-1-fengc@google.com> X-Mailer: git-send-email 2.22.0.rc2.383.gf4fbbf30c2-goog Subject: [PATCH v4 1/3] dma-buf: give each buffer a full-fledged inode From: Chenbo Feng To: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: Sumit Semwal , kernel-team@android.com Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg Hackmann By traversing /proc/*/fd and /proc/*/map_files, processes with CAP_ADMIN can get a lot of fine-grained data about how shmem buffers are shared among processes. stat(2) on each entry gives the caller a unique ID (st_ino), the buffer's size (st_size), and even the number of pages currently charged to the buffer (st_blocks / 512). In contrast, all dma-bufs share the same anonymous inode. So while we can count how many dma-buf fds or mappings a process has, we can't get the size of the backing buffers or tell if two entries point to the same dma-buf. On systems with debugfs, we can get a per-buffer breakdown of size and reference count, but can't tell which processes are actually holding the references to each buffer. Replace the singleton inode with full-fledged inodes allocated by alloc_anon_inode(). This involves creating and mounting a mini-pseudo-filesystem for dma-buf, following the example in fs/aio.c. Signed-off-by: Greg Hackmann Signed-off-by: Chenbo Feng --- drivers/dma-buf/dma-buf.c | 63 ++++++++++++++++++++++++++++++++++---- include/uapi/linux/magic.h | 1 + 2 files changed, 58 insertions(+), 6 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 7c858020d14b..ffd5a2ad7d6f 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -34,8 +34,10 @@ #include #include #include +#include #include +#include static inline int is_dma_buf_file(struct file *); @@ -46,6 +48,25 @@ struct dma_buf_list { static struct dma_buf_list db_list; +static const struct dentry_operations dma_buf_dentry_ops = { + .d_dname = simple_dname, +}; + +static struct vfsmount *dma_buf_mnt; + +static struct dentry *dma_buf_fs_mount(struct file_system_type *fs_type, + int flags, const char *name, void *data) +{ + return mount_pseudo(fs_type, "dmabuf:", NULL, &dma_buf_dentry_ops, + DMA_BUF_MAGIC); +} + +static struct file_system_type dma_buf_fs_type = { + .name = "dmabuf", + .mount = dma_buf_fs_mount, + .kill_sb = kill_anon_super, +}; + static int dma_buf_release(struct inode *inode, struct file *file) { struct dma_buf *dmabuf; @@ -338,6 +359,31 @@ static inline int is_dma_buf_file(struct file *file) return file->f_op == &dma_buf_fops; } +static struct file *dma_buf_getfile(struct dma_buf *dmabuf, int flags) +{ + struct file *file; + struct inode *inode = alloc_anon_inode(dma_buf_mnt->mnt_sb); + + if (IS_ERR(inode)) + return ERR_CAST(inode); + + inode->i_size = dmabuf->size; + inode_set_bytes(inode, dmabuf->size); + + file = alloc_file_pseudo(inode, dma_buf_mnt, "dmabuf", + flags, &dma_buf_fops); + if (IS_ERR(file)) + goto err_alloc_file; + file->f_flags = flags & (O_ACCMODE | O_NONBLOCK); + file->private_data = dmabuf; + + return file; + +err_alloc_file: + iput(inode); + return file; +} + /** * DOC: dma buf device access * @@ -433,8 +479,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) } dmabuf->resv = resv; - file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, - exp_info->flags); + file = dma_buf_getfile(dmabuf, exp_info->flags); if (IS_ERR(file)) { ret = PTR_ERR(file); goto err_dmabuf; @@ -1025,8 +1070,8 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) return ret; seq_puts(s, "\nDma-buf Objects:\n"); - seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\n", - "size", "flags", "mode", "count"); + seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\n", + "size", "flags", "mode", "count", "ino"); list_for_each_entry(buf_obj, &db_list.head, list_node) { ret = mutex_lock_interruptible(&buf_obj->lock); @@ -1037,11 +1082,12 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) continue; } - seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n", + seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\n", buf_obj->size, buf_obj->file->f_flags, buf_obj->file->f_mode, file_count(buf_obj->file), - buf_obj->exp_name); + buf_obj->exp_name, + file_inode(buf_obj->file)->i_ino); robj = buf_obj->resv; while (true) { @@ -1136,6 +1182,10 @@ static inline void dma_buf_uninit_debugfs(void) static int __init dma_buf_init(void) { + dma_buf_mnt = kern_mount(&dma_buf_fs_type); + if (IS_ERR(dma_buf_mnt)) + return PTR_ERR(dma_buf_mnt); + mutex_init(&db_list.lock); INIT_LIST_HEAD(&db_list.head); dma_buf_init_debugfs(); @@ -1146,5 +1196,6 @@ subsys_initcall(dma_buf_init); static void __exit dma_buf_deinit(void) { dma_buf_uninit_debugfs(); + kern_unmount(dma_buf_mnt); } __exitcall(dma_buf_deinit); diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h index f8c00045d537..665e18627f78 100644 --- a/include/uapi/linux/magic.h +++ b/include/uapi/linux/magic.h @@ -91,5 +91,6 @@ #define UDF_SUPER_MAGIC 0x15013346 #define BALLOON_KVM_MAGIC 0x13661366 #define ZSMALLOC_MAGIC 0x58295829 +#define DMA_BUF_MAGIC 0x444d4142 /* "DMAB" */ #endif /* __LINUX_MAGIC_H__ */ -- 2.22.0.rc2.383.gf4fbbf30c2-goog