From patchwork Fri Jan 18 16:12:16 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10770793 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 202A213B4 for ; Fri, 18 Jan 2019 16:12:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0F2852F3B0 for ; Fri, 18 Jan 2019 16:12:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0360E2F562; Fri, 18 Jan 2019 16:12:55 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 924542F3B0 for ; Fri, 18 Jan 2019 16:12:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728018AbfARQMy (ORCPT ); Fri, 18 Jan 2019 11:12:54 -0500 Received: from mail-pf1-f193.google.com ([209.85.210.193]:41697 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727970AbfARQMx (ORCPT ); Fri, 18 Jan 2019 11:12:53 -0500 Received: by mail-pf1-f193.google.com with SMTP id b7so6807542pfi.8 for ; Fri, 18 Jan 2019 08:12:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=scNBCeOhysecepgCupm97WAYtsMfIFMGuolJ4I0NyhI=; b=Mm8Klr0VlMn+uHHmK19HjssOCsJ9BSauCBSZ0y1xlQS9ZVpPqZfSQTc8WX2417R0Wr 3NSiVzRKSRNVKeFDpg7BTHy3jH0KNnRWMkLKDzm3rJL7tBCETouziIpnlPMPLDKkPIep YKhYV1u7RZJLCtf+hd//aLCkmHFkhkMNTlRwB0WtnGK2TIwxMVuHjt+pxQgW+WuAd/jw 49R3LIeZBe9kGNWH92C0EmmqVaKlh6FZE4iPjXcK+9vTGL7l4CRT/2N2BAPDNis/nHai BAxyjgG0QTs8ERTZmQaR0yqH2RuBF2e8SmsiOtVdTXUUyfKeif3DdmU6MY37aih0ebKB HP5g== 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:in-reply-to :references; bh=scNBCeOhysecepgCupm97WAYtsMfIFMGuolJ4I0NyhI=; b=npijGGY71wTKwBrxB3tuJtLHSFN1VMQxzyLhHJgxTAd+Zx27KJUbSxC99UngLmCFnn D3yVO443877VjSBhA6C8JcSMcP+CxJSg5EVDFBpaD1gzN9J1FdqnOXceVDjc6ogyL3rS i4yS5iMq0Bzs08JC0Nepu1fjBgIoHX5xq1ztMTMRCUnT09DbWa0/jtZt9VkCdT/wDEwH rG+Spli5ZLizH0kC0DbvoWDLBURCRHp9F/8Tb7nC1buFEqMrRi358os9TnDITIu3RtKd thwD6mIok0czY0WQ7z1TbmwmxxuS1MVsFhx8GbZ8gg/ae3yX3RyYSZeaYohVf4isJ+T2 s6+Q== X-Gm-Message-State: AJcUukdd7D7OGHygj4dLnlSo1qfLjckA7MteMP3KFDbS7FJl6wFfEyAY M44XshoUcSuuFXbZ41m7uOINk9auXwgbhA== X-Google-Smtp-Source: ALg8bN5COQ7Tg15kfRtNuoZBfYdoyaJdaA2y7hZihHtqW40cCktTgr3Tb9IEVjDUjwm350rK04z0XQ== X-Received: by 2002:a63:955a:: with SMTP id t26mr18504527pgn.449.1547827971782; Fri, 18 Jan 2019 08:12:51 -0800 (PST) Received: from x1.localdomain (66.29.188.166.static.utbb.net. [66.29.188.166]) by smtp.gmail.com with ESMTPSA id m20sm5317804pgv.93.2019.01.18.08.12.49 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 Jan 2019 08:12:50 -0800 (PST) From: Jens Axboe To: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 08/17] fs: add fget_many() and fput_many() Date: Fri, 18 Jan 2019 09:12:16 -0700 Message-Id: <20190118161225.4545-9-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190118161225.4545-1-axboe@kernel.dk> References: <20190118161225.4545-1-axboe@kernel.dk> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Some uses cases repeatedly get and put references to the same file, but the only exposed interface is doing these one at the time. As each of these entail an atomic inc or dec on a shared structure, that cost can add up. Add fget_many(), which works just like fget(), except it takes an argument for how many references to get on the file. Ditto fput_many(), which can drop an arbitrary number of references to a file. Signed-off-by: Jens Axboe --- fs/file.c | 15 ++++++++++----- fs/file_table.c | 9 +++++++-- include/linux/file.h | 2 ++ include/linux/fs.h | 4 +++- 4 files changed, 22 insertions(+), 8 deletions(-) diff --git a/fs/file.c b/fs/file.c index 3209ee271c41..e0d7ce70e860 100644 --- a/fs/file.c +++ b/fs/file.c @@ -705,7 +705,7 @@ void do_close_on_exec(struct files_struct *files) spin_unlock(&files->file_lock); } -static struct file *__fget(unsigned int fd, fmode_t mask) +static struct file *__fget(unsigned int fd, fmode_t mask, unsigned int refs) { struct files_struct *files = current->files; struct file *file; @@ -720,7 +720,7 @@ static struct file *__fget(unsigned int fd, fmode_t mask) */ if (file->f_mode & mask) file = NULL; - else if (!get_file_rcu(file)) + else if (!get_file_rcu_many(file, refs)) goto loop; } rcu_read_unlock(); @@ -728,15 +728,20 @@ static struct file *__fget(unsigned int fd, fmode_t mask) return file; } +struct file *fget_many(unsigned int fd, unsigned int refs) +{ + return __fget(fd, FMODE_PATH, refs); +} + struct file *fget(unsigned int fd) { - return __fget(fd, FMODE_PATH); + return fget_many(fd, 1); } EXPORT_SYMBOL(fget); struct file *fget_raw(unsigned int fd) { - return __fget(fd, 0); + return __fget(fd, 0, 1); } EXPORT_SYMBOL(fget_raw); @@ -767,7 +772,7 @@ static unsigned long __fget_light(unsigned int fd, fmode_t mask) return 0; return (unsigned long)file; } else { - file = __fget(fd, mask); + file = __fget(fd, mask, 1); if (!file) return 0; return FDPUT_FPUT | (unsigned long)file; diff --git a/fs/file_table.c b/fs/file_table.c index 5679e7fcb6b0..155d7514a094 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -326,9 +326,9 @@ void flush_delayed_fput(void) static DECLARE_DELAYED_WORK(delayed_fput_work, delayed_fput); -void fput(struct file *file) +void fput_many(struct file *file, unsigned int refs) { - if (atomic_long_dec_and_test(&file->f_count)) { + if (atomic_long_sub_and_test(refs, &file->f_count)) { struct task_struct *task = current; if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) { @@ -347,6 +347,11 @@ void fput(struct file *file) } } +void fput(struct file *file) +{ + fput_many(file, 1); +} + /* * synchronous analog of fput(); for kernel threads that might be needed * in some umount() (and thus can't use flush_delayed_fput() without diff --git a/include/linux/file.h b/include/linux/file.h index 6b2fb032416c..3fcddff56bc4 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -13,6 +13,7 @@ struct file; extern void fput(struct file *); +extern void fput_many(struct file *, unsigned int); struct file_operations; struct vfsmount; @@ -44,6 +45,7 @@ static inline void fdput(struct fd fd) } extern struct file *fget(unsigned int fd); +extern struct file *fget_many(unsigned int fd, unsigned int refs); extern struct file *fget_raw(unsigned int fd); extern unsigned long __fdget(unsigned int fd); extern unsigned long __fdget_raw(unsigned int fd); diff --git a/include/linux/fs.h b/include/linux/fs.h index ccb0b7a63aa5..acaad78b6781 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -952,7 +952,9 @@ static inline struct file *get_file(struct file *f) atomic_long_inc(&f->f_count); return f; } -#define get_file_rcu(x) atomic_long_inc_not_zero(&(x)->f_count) +#define get_file_rcu_many(x, cnt) \ + atomic_long_add_unless(&(x)->f_count, (cnt), 0) +#define get_file_rcu(x) get_file_rcu_many((x), 1) #define fput_atomic(x) atomic_long_add_unless(&(x)->f_count, -1, 1) #define file_count(x) atomic_long_read(&(x)->f_count)