From patchwork Wed Jan 16 17:49:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10766517 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 BE1B713B4 for ; Wed, 16 Jan 2019 17:50:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AF2EB2EF93 for ; Wed, 16 Jan 2019 17:50:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AD73A2EFA2; Wed, 16 Jan 2019 17:50:30 +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 487AA2EFAF for ; Wed, 16 Jan 2019 17:50:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727721AbfAPRu3 (ORCPT ); Wed, 16 Jan 2019 12:50:29 -0500 Received: from mail-it1-f195.google.com ([209.85.166.195]:55983 "EHLO mail-it1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727682AbfAPRu2 (ORCPT ); Wed, 16 Jan 2019 12:50:28 -0500 Received: by mail-it1-f195.google.com with SMTP id m62so4368013ith.5 for ; Wed, 16 Jan 2019 09:50:27 -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=KUkWfNfAwzOsYUappIVQ3wQO5c0RI0RVWA9luoA5JxT7r2kpQGBI3ozhoypllKk8rs Si2eOsOHg6B5dfhwVdq9hCbw8l1XI8XgoYChm8nudSNbDfsAPVt3gVrSnqRJ7yhTMTG2 PCHSQqt8JCTDQ6gdxaY8RwApCpU6KCPRNU8XLUWX2GI/KnXt1jJgUxXFlTWqDrU7IiPR IAyvYHNURt+WY8KDnJLZAAW1H8qKKq1AvY3DgDxEzMutBSVJvtX8F/2XevZj0wkaIQ6Y wxSxUlkSznCKAb7s8pFER7fjq/9Njh47r/bX1id2F/zjRy8GFUFeO6BAA4GK4widejc1 WPKA== 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=bcalSSP7w2QlkPuZI1NQXOzzTxRdMs73dbZzjJ+1z6LJiYC/hN8Pq89WSzvrAx35aW 4oe0xqKtlMyNvzhL90IpMXA1jM3nCjLgQwDBeUjoL0KfcXBzgBMlJZhJ2Yvrqh+tVrBd 7fwe/em/8infKN5m7xbw6ImsLkGnkQlrrqXgBrb2YxUBL0ueIQvLB2+OifcAWZb65RHm ACJ358t6jw5hDoueMcZUgxJybw32DS9UDpMvIIvVeFqrjY9qKjt6WbAsXaOulboJhEYc 1YTNAnAPFWBfnmUFMyWQSOKjbREFXvUvvjcjH1oyraLDfdra97HYnqqDzHmwJ2517Be8 dYHQ== X-Gm-Message-State: AJcUukfDai5Y77KPomC9fONHA4iGdLWiuBz+N1692jAzEpfoVbqNwaM6 m6AIq/eaYNzmDwRjoldsHHUxd+VY3czGrA== X-Google-Smtp-Source: ALg8bN73QvlAwdPC6SdjczMFygU0EfjVWQ/CRqJ18DSYo2IoOL/4a8RbfN7/N3Ob3f5Sq+ai9rjSZQ== X-Received: by 2002:a24:4545:: with SMTP id y66mr5830905ita.174.1547661026358; Wed, 16 Jan 2019 09:50:26 -0800 (PST) Received: from x1.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id x128sm3705690itb.8.2019.01.16.09.50.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 16 Jan 2019 09:50:25 -0800 (PST) From: Jens Axboe To: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 08/15] fs: add fget_many() and fput_many() Date: Wed, 16 Jan 2019 10:49:56 -0700 Message-Id: <20190116175003.17880-9-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190116175003.17880-1-axboe@kernel.dk> References: <20190116175003.17880-1-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)