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=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 5207FC4742C for ; Mon, 2 Nov 2020 15:26:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E472A22258 for ; Mon, 2 Nov 2020 15:26:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="q3c491Bb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726478AbgKBP0Z (ORCPT ); Mon, 2 Nov 2020 10:26:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57702 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725837AbgKBP0Z (ORCPT ); Mon, 2 Nov 2020 10:26:25 -0500 Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 218FCC0617A6; Mon, 2 Nov 2020 07:26:23 -0800 (PST) Received: by mail-wr1-x443.google.com with SMTP id s9so15063934wro.8; Mon, 02 Nov 2020 07:26:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=cn/shGY0wsvTmqkCSMzjGPR8S0h4YbMWhEsFZ2K9gZs=; b=q3c491BbAqC2pfEe412KOu2zPomE6klOl4qZkcVYi7NwJfGePROFL/KSBLD57IcLts BtJjRgGh1qQWROLaLrZ+i2IbHTFXb8eDmrbPLDE7fQgijuMrjKfqAshNM9N7WJQOF9Tf bYTN0C34XUD+tAr/v1l4/el+5SXSylQUto33WIha8wAB4DBLjOIK6qKg7o8NqPXM7MQu 9qgq8zNvPJkUZcO3JWj0q/QGGhVeMpg3wgYC2m6Bigy9bt+l8dFBDwMT1wkNwscij9pl biwhOG4eTgjhIWU5IwH5Oi/tb2swCIobw19nS6FOxd0d8ITnp5bLsxLZxjoXJg0NJsIp 4aiA== 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:mime-version:content-transfer-encoding; bh=cn/shGY0wsvTmqkCSMzjGPR8S0h4YbMWhEsFZ2K9gZs=; b=RFbnKZO7FQ4xF60RxuLTSJJ+RYVeEvp44PymPeyiQhRDTLfqFPCSAgppJbr2SLZ+q2 uDt4FTdZ/2zan6J/wHybQfgTrH9jjMrcz1dWATTTUsX5iuiGcAFLH+sd2SUkqcnFuGq5 OB+2sJ890qI3Ky+q0o2Hz4rV4jE/0IDnoKx4je+WKgFXw2iNDSTiMB+NuHIeB3nk3410 v3mQncsbQn5eYuNjqpkKKR8QPlLxfXRDFJPcstUH5DDBvXho6UZSt/NBO1HzB94TpGnD rLca57m9TGDLGsxNZ6XoyJVZpgXoWemx/fptBRAfoFDMUTrMR1fiGZUj9/TxJh7OwKMQ s13Q== X-Gm-Message-State: AOAM532KqENAiFHzjIkZbDqVnEVDvO3pc5CJHyI/zZkjC5rMDcgzvhLw APAWWvgz5CAdOQiUkuTivV0= X-Google-Smtp-Source: ABdhPJy/YocqLwtU7Hod+yfT4grIGnn9M3vhBpCz8qHZJg66qzhpldvar73pVqVHLHcwL7mRBGl8bA== X-Received: by 2002:adf:ea11:: with SMTP id q17mr22126399wrm.251.1604330781619; Mon, 02 Nov 2020 07:26:21 -0800 (PST) Received: from localhost.localdomain ([170.253.60.68]) by smtp.googlemail.com with ESMTPSA id s133sm9344364wmf.30.2020.11.02.07.26.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Nov 2020 07:26:20 -0800 (PST) From: Alejandro Colomar To: Benjamin LaHaise Cc: Alejandro Colomar , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] fs/aio.c: Cosmetic Date: Mon, 2 Nov 2020 16:24:41 +0100 Message-Id: <20201102152439.315640-1-colomar.6.4.3@gmail.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201102150507.314164-1-colomar.6.4.3@gmail.com> References: <20201102150507.314164-1-colomar.6.4.3@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Changes: - Consistently use 'unsigned int', instead of 'unsigned'. - Add a blank line after variable declarations. - Move variable declarations to the top of functions. - Add a blank line at the top of functions if there are no declarations. - Invert logic of 'if's to reduce indentation and simplify function logic. - Add goto tags when needed. - Early return when appropriate. - Add braces to 'else' if the corresponding 'if' used braces. - Replace spaces by tabs This patch does not introduce any actual changes in behavior. Signed-off-by: Alejandro Colomar --- [[ CC: fix typo in kvack.org ]] Hello Benjamin, I found some inconsistencies in the code here when fixing the manual page for io_setup(3). I compiled the whole fs (`make fs`): I used the .config file from debian testing. No warnings; it compiles fine after the changes. However I didn't compile the whole kernel (my system got out of space :( ). This patch should not change any behavior. Cheers, Alex P.S.: I resent the email as I had a typo in the list email. fs/aio.c | 390 +++++++++++++++++++++++++++++-------------------------- 1 file changed, 208 insertions(+), 182 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index d5ec30385566..9d7dc92a6d7d 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -55,16 +55,16 @@ #define AIO_RING_COMPAT_FEATURES 1 #define AIO_RING_INCOMPAT_FEATURES 0 struct aio_ring { - unsigned id; /* kernel internal index number */ - unsigned nr; /* number of io_events */ - unsigned head; /* Written to by userland or under ring_lock + unsigned int id; /* kernel internal index number */ + unsigned int nr; /* number of io_events */ + unsigned int head; /* Written to by userland or under ring_lock * mutex by aio_read_events_ring(). */ - unsigned tail; + unsigned int tail; - unsigned magic; - unsigned compat_features; - unsigned incompat_features; - unsigned header_length; /* size of aio_ring */ + unsigned int magic; + unsigned int compat_features; + unsigned int incompat_features; + unsigned int header_length; /* size of aio_ring */ struct io_event io_events[]; @@ -80,12 +80,12 @@ struct aio_ring { struct kioctx_table { struct rcu_head rcu; - unsigned nr; + unsigned int nr; struct kioctx __rcu *table[]; }; struct kioctx_cpu { - unsigned reqs_available; + unsigned int reqs_available; }; struct ctx_rq_wait { @@ -107,7 +107,7 @@ struct kioctx { * For percpu reqs_available, number of slots we move to/from global * counter at a time: */ - unsigned req_batch; + unsigned int req_batch; /* * This is what userspace passed to io_setup(), it's not used for * anything but counting against the global max_reqs quota. @@ -115,10 +115,10 @@ struct kioctx { * The real limit is nr_events - 1, which will be larger (see * aio_setup_ring()) */ - unsigned max_reqs; + unsigned int max_reqs; /* Size of ringbuffer, in units of struct io_event */ - unsigned nr_events; + unsigned int nr_events; unsigned long mmap_base; unsigned long mmap_size; @@ -156,15 +156,15 @@ struct kioctx { } ____cacheline_aligned_in_smp; struct { - unsigned tail; - unsigned completed_events; + unsigned int tail; + unsigned int completed_events; spinlock_t completion_lock; } ____cacheline_aligned_in_smp; struct page *internal_pages[AIO_RING_PAGES]; struct file *aio_ring_file; - unsigned id; + unsigned int id; }; /* @@ -236,6 +236,7 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages) { struct file *file; struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb); + if (IS_ERR(inode)) return ERR_CAST(inode); @@ -252,6 +253,7 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages) static int aio_init_fs_context(struct fs_context *fc) { + if (!init_pseudo(fc, AIO_RING_MAGIC)) return -ENOMEM; fc->s_iflags |= SB_I_NOEXEC; @@ -269,6 +271,7 @@ static int __init aio_setup(void) .init_fs_context = aio_init_fs_context, .kill_sb = kill_anon_super, }; + aio_mnt = kern_mount(&aio_fs); if (IS_ERR(aio_mnt)) panic("Failed to create aio fs mount."); @@ -284,18 +287,19 @@ static void put_aio_ring_file(struct kioctx *ctx) struct file *aio_ring_file = ctx->aio_ring_file; struct address_space *i_mapping; - if (aio_ring_file) { - truncate_setsize(file_inode(aio_ring_file), 0); + if (!aio_ring_file) + return; - /* Prevent further access to the kioctx from migratepages */ - i_mapping = aio_ring_file->f_mapping; - spin_lock(&i_mapping->private_lock); - i_mapping->private_data = NULL; - ctx->aio_ring_file = NULL; - spin_unlock(&i_mapping->private_lock); + truncate_setsize(file_inode(aio_ring_file), 0); - fput(aio_ring_file); - } + /* Prevent further access to the kioctx from migratepages */ + i_mapping = aio_ring_file->f_mapping; + spin_lock(&i_mapping->private_lock); + i_mapping->private_data = NULL; + ctx->aio_ring_file = NULL; + spin_unlock(&i_mapping->private_lock); + + fput(aio_ring_file); } static void aio_free_ring(struct kioctx *ctx) @@ -363,6 +367,7 @@ static const struct vm_operations_struct aio_ring_vm_ops = { static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma) { + vma->vm_flags |= VM_DONTEXPAND; vma->vm_ops = &aio_ring_vm_ops; return 0; @@ -413,8 +418,9 @@ static int aio_migratepage(struct address_space *mapping, struct page *new, /* Make sure the old page hasn't already been changed */ if (ctx->ring_pages[idx] != old) rc = -EAGAIN; - } else + } else { rc = -EINVAL; + } if (rc != 0) goto out_unlock; @@ -632,7 +638,7 @@ static void free_ioctx_users(struct percpu_ref *ref) static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) { - unsigned i, new_nr; + unsigned int i, new_nr; struct kioctx_table *table, *old; struct aio_ring *ring; @@ -640,23 +646,27 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) table = rcu_dereference_raw(mm->ioctx_table); while (1) { - if (table) - for (i = 0; i < table->nr; i++) - if (!rcu_access_pointer(table->table[i])) { - ctx->id = i; - rcu_assign_pointer(table->table[i], ctx); - spin_unlock(&mm->ioctx_lock); - - /* While kioctx setup is in progress, - * we are protected from page migration - * changes ring_pages by ->ring_lock. - */ - ring = kmap_atomic(ctx->ring_pages[0]); - ring->id = ctx->id; - kunmap_atomic(ring); - return 0; - } - + if (!table) + goto new_table; + + for (i = 0; i < table->nr; i++) { + if (rcu_access_pointer(table->table[i])) + continue; + + ctx->id = i; + rcu_assign_pointer(table->table[i], ctx); + spin_unlock(&mm->ioctx_lock); + + /* While kioctx setup is in progress, + * we are protected from page migration + * changes ring_pages by ->ring_lock. + */ + ring = kmap_atomic(ctx->ring_pages[0]); + ring->id = ctx->id; + kunmap_atomic(ring); + return 0; + } +new_table: new_nr = (table ? table->nr : 1) * 4; spin_unlock(&mm->ioctx_lock); @@ -685,8 +695,9 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) } } -static void aio_nr_sub(unsigned nr) +static void aio_nr_sub(unsigned int nr) { + spin_lock(&aio_nr_lock); if (WARN_ON(aio_nr - nr > aio_nr)) aio_nr = 0; @@ -698,7 +709,7 @@ static void aio_nr_sub(unsigned nr) /* ioctx_alloc * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. */ -static struct kioctx *ioctx_alloc(unsigned nr_events) +static struct kioctx *ioctx_alloc(unsigned int nr_events) { struct mm_struct *mm = current->mm; struct kioctx *ctx; @@ -899,7 +910,7 @@ void exit_aio(struct mm_struct *mm) kfree(table); } -static void put_reqs_available(struct kioctx *ctx, unsigned nr) +static void put_reqs_available(struct kioctx *ctx, unsigned int nr) { struct kioctx_cpu *kcpu; unsigned long flags; @@ -924,21 +935,23 @@ static bool __get_reqs_available(struct kioctx *ctx) local_irq_save(flags); kcpu = this_cpu_ptr(ctx->cpu); - if (!kcpu->reqs_available) { - int old, avail = atomic_read(&ctx->reqs_available); + if (kcpu->reqs_available) + goto kcpu_reqs_avail; + + int old, avail = atomic_read(&ctx->reqs_available); - do { - if (avail < ctx->req_batch) - goto out; + do { + if (avail < ctx->req_batch) + goto out; - old = avail; - avail = atomic_cmpxchg(&ctx->reqs_available, - avail, avail - ctx->req_batch); - } while (avail != old); + old = avail; + avail = atomic_cmpxchg(&ctx->reqs_available, + avail, avail - ctx->req_batch); + } while (avail != old); - kcpu->reqs_available += ctx->req_batch; - } + kcpu->reqs_available += ctx->req_batch; +kcpu_reqs_avail: ret = true; kcpu->reqs_available--; out: @@ -953,10 +966,10 @@ static bool __get_reqs_available(struct kioctx *ctx) * from aio_get_req() (the we're out of events case). It must be * called holding ctx->completion_lock. */ -static void refill_reqs_available(struct kioctx *ctx, unsigned head, - unsigned tail) +static void refill_reqs_available(struct kioctx *ctx, unsigned int head, + unsigned int tail) { - unsigned events_in_ring, completed; + unsigned int events_in_ring, completed; /* Clamp head since userland can write to it. */ head %= ctx->nr_events; @@ -984,32 +997,34 @@ static void refill_reqs_available(struct kioctx *ctx, unsigned head, */ static void user_refill_reqs_available(struct kioctx *ctx) { + struct aio_ring *ring; + unsigned int head; + spin_lock_irq(&ctx->completion_lock); - if (ctx->completed_events) { - struct aio_ring *ring; - unsigned head; - - /* Access of ring->head may race with aio_read_events_ring() - * here, but that's okay since whether we read the old version - * or the new version, and either will be valid. The important - * part is that head cannot pass tail since we prevent - * aio_complete() from updating tail by holding - * ctx->completion_lock. Even if head is invalid, the check - * against ctx->completed_events below will make sure we do the - * safe/right thing. - */ - ring = kmap_atomic(ctx->ring_pages[0]); - head = ring->head; - kunmap_atomic(ring); + if (!ctx->completed_events) + goto out; - refill_reqs_available(ctx, head, ctx->tail); - } + /* Access of ring->head may race with aio_read_events_ring() + * here, but that's okay since whether we read the old version + * or the new version, and either will be valid. The important + * part is that head cannot pass tail since we prevent + * aio_complete() from updating tail by holding + * ctx->completion_lock. Even if head is invalid, the check + * against ctx->completed_events below will make sure we do the + * safe/right thing. + */ + ring = kmap_atomic(ctx->ring_pages[0]); + head = ring->head; + kunmap_atomic(ring); + refill_reqs_available(ctx, head, ctx->tail); +out: spin_unlock_irq(&ctx->completion_lock); } static bool get_reqs_available(struct kioctx *ctx) { + if (__get_reqs_available(ctx)) return true; user_refill_reqs_available(ctx); @@ -1050,7 +1065,7 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id) struct mm_struct *mm = current->mm; struct kioctx *ctx, *ret = NULL; struct kioctx_table *table; - unsigned id; + unsigned int id; if (get_user(id, &ring->id)) return NULL; @@ -1074,6 +1089,7 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id) static inline void iocb_destroy(struct aio_kiocb *iocb) { + if (iocb->ki_eventfd) eventfd_ctx_put(iocb->ki_eventfd); if (iocb->ki_filp) @@ -1090,7 +1106,7 @@ static void aio_complete(struct aio_kiocb *iocb) struct kioctx *ctx = iocb->ki_ctx; struct aio_ring *ring; struct io_event *ev_page, *event; - unsigned tail, pos, head; + unsigned int tail, pos, head; unsigned long flags; /* @@ -1160,10 +1176,11 @@ static void aio_complete(struct aio_kiocb *iocb) static inline void iocb_put(struct aio_kiocb *iocb) { - if (refcount_dec_and_test(&iocb->ki_refcnt)) { - aio_complete(iocb); - iocb_destroy(iocb); - } + + if (!refcount_dec_and_test(&iocb->ki_refcnt)) + return; + aio_complete(iocb); + iocb_destroy(iocb); } /* aio_read_events_ring @@ -1174,7 +1191,7 @@ static long aio_read_events_ring(struct kioctx *ctx, struct io_event __user *event, long nr) { struct aio_ring *ring; - unsigned head, tail, pos; + unsigned int head, tail, pos; long ret = 0; int copy_ret; @@ -1309,7 +1326,7 @@ static long read_events(struct kioctx *ctx, long min_nr, long nr, * pointer is passed for ctxp. Will fail with -ENOSYS if not * implemented. */ -SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) +SYSCALL_DEFINE2(io_setup, unsigned int, nr_events, aio_context_t __user *, ctxp) { struct kioctx *ioctx = NULL; unsigned long ctx; @@ -1328,19 +1345,19 @@ SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) ioctx = ioctx_alloc(nr_events); ret = PTR_ERR(ioctx); - if (!IS_ERR(ioctx)) { - ret = put_user(ioctx->user_id, ctxp); - if (ret) - kill_ioctx(current->mm, ioctx, NULL); - percpu_ref_put(&ioctx->users); - } + if (IS_ERR(ioctx)) + goto out; + ret = put_user(ioctx->user_id, ctxp); + if (ret) + kill_ioctx(current->mm, ioctx, NULL); + percpu_ref_put(&ioctx->users); out: return ret; } #ifdef CONFIG_COMPAT -COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p) +COMPAT_SYSCALL_DEFINE2(io_setup, unsigned int, nr_events, u32 __user *, ctx32p) { struct kioctx *ioctx = NULL; unsigned long ctx; @@ -1359,13 +1376,13 @@ COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p) ioctx = ioctx_alloc(nr_events); ret = PTR_ERR(ioctx); - if (!IS_ERR(ioctx)) { - /* truncating is ok because it's a user address */ - ret = put_user((u32)ioctx->user_id, ctx32p); - if (ret) - kill_ioctx(current->mm, ioctx, NULL); - percpu_ref_put(&ioctx->users); - } + if (IS_ERR(ioctx)) + goto out; + /* truncating is ok because it's a user address */ + ret = put_user((u32)ioctx->user_id, ctx32p); + if (ret) + kill_ioctx(current->mm, ioctx, NULL); + percpu_ref_put(&ioctx->users); out: return ret; @@ -1381,31 +1398,32 @@ COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p) SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) { struct kioctx *ioctx = lookup_ioctx(ctx); - if (likely(NULL != ioctx)) { - struct ctx_rq_wait wait; - int ret; + struct ctx_rq_wait wait; + int ret; - init_completion(&wait.comp); - atomic_set(&wait.count, 1); + if (unlikely(!ioctx)) { + pr_debug("EINVAL: invalid context id\n"); + return -EINVAL; + } - /* Pass requests_done to kill_ioctx() where it can be set - * in a thread-safe way. If we try to set it here then we have - * a race condition if two io_destroy() called simultaneously. - */ - ret = kill_ioctx(current->mm, ioctx, &wait); - percpu_ref_put(&ioctx->users); + init_completion(&wait.comp); + atomic_set(&wait.count, 1); - /* Wait until all IO for the context are done. Otherwise kernel - * keep using user-space buffers even if user thinks the context - * is destroyed. - */ - if (!ret) - wait_for_completion(&wait.comp); + /* Pass requests_done to kill_ioctx() where it can be set + * in a thread-safe way. If we try to set it here then we have + * a race condition if two io_destroy() called simultaneously. + */ + ret = kill_ioctx(current->mm, ioctx, &wait); + percpu_ref_put(&ioctx->users); - return ret; - } - pr_debug("EINVAL: invalid context id\n"); - return -EINVAL; + /* Wait until all IO for the context are done. Otherwise kernel + * keep using user-space buffers even if user thinks the context + * is destroyed. + */ + if (!ret) + wait_for_completion(&wait.comp); + + return ret; } static void aio_remove_iocb(struct aio_kiocb *iocb) @@ -1466,8 +1484,9 @@ static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb) } req->ki_ioprio = iocb->aio_reqprio; - } else + } else { req->ki_ioprio = get_current_ioprio(); + } ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags); if (unlikely(ret)) @@ -1499,6 +1518,7 @@ static ssize_t aio_setup_rw(int rw, const struct iocb *iocb, static inline void aio_rw_done(struct kiocb *req, ssize_t ret) { + switch (ret) { case -EIOCBQUEUED: break; @@ -1567,21 +1587,23 @@ static int aio_write(struct kiocb *req, const struct iocb *iocb, if (ret < 0) return ret; ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter)); - if (!ret) { - /* - * Open-code file_start_write here to grab freeze protection, - * which will be released by another thread in - * aio_complete_rw(). Fool lockdep by telling it the lock got - * released so that it doesn't complain about the held lock when - * we return to userspace. - */ - if (S_ISREG(file_inode(file)->i_mode)) { - __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true); - __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE); - } - req->ki_flags |= IOCB_WRITE; - aio_rw_done(req, call_write_iter(file, req, &iter)); + if (ret) + goto out; + + /* + * Open-code file_start_write here to grab freeze protection, + * which will be released by another thread in + * aio_complete_rw(). Fool lockdep by telling it the lock got + * released so that it doesn't complain about the held lock when + * we return to userspace. + */ + if (S_ISREG(file_inode(file)->i_mode)) { + __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true); + __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE); } + req->ki_flags |= IOCB_WRITE; + aio_rw_done(req, call_write_iter(file, req, &iter)); +out: kfree(iovec); return ret; } @@ -1674,8 +1696,8 @@ static int aio_poll_cancel(struct kiocb *iocb) return 0; } -static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, - void *key) +static int aio_poll_wake(struct wait_queue_entry *wait, unsigned int mode, + int sync, void *key) { struct poll_iocb *req = container_of(wait, struct poll_iocb, wait); struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll); @@ -1688,29 +1710,31 @@ static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, list_del_init(&req->wait.entry); - if (mask && spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) { - struct kioctx *ctx = iocb->ki_ctx; + if (!(mask && spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags))) { + schedule_work(&req->work); + return 1; + } - /* - * Try to complete the iocb inline if we can. Use - * irqsave/irqrestore because not all filesystems (e.g. fuse) - * call this function with IRQs disabled and because IRQs - * have to be disabled before ctx_lock is obtained. - */ - list_del(&iocb->ki_list); - iocb->ki_res.res = mangle_poll(mask); - req->done = true; - if (iocb->ki_eventfd && eventfd_signal_count()) { - iocb = NULL; - INIT_WORK(&req->work, aio_poll_put_work); - schedule_work(&req->work); - } - spin_unlock_irqrestore(&ctx->ctx_lock, flags); - if (iocb) - iocb_put(iocb); - } else { + struct kioctx *ctx = iocb->ki_ctx; + + /* + * Try to complete the iocb inline if we can. Use + * irqsave/irqrestore because not all filesystems (e.g. fuse) + * call this function with IRQs disabled and because IRQs + * have to be disabled before ctx_lock is obtained. + */ + list_del(&iocb->ki_list); + iocb->ki_res.res = mangle_poll(mask); + req->done = true; + if (iocb->ki_eventfd && eventfd_signal_count()) { + iocb = NULL; + INIT_WORK(&req->work, aio_poll_put_work); schedule_work(&req->work); } + spin_unlock_irqrestore(&ctx->ctx_lock, flags); + if (iocb) + iocb_put(iocb); + return 1; } @@ -1770,24 +1794,25 @@ static int aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb) mask = vfs_poll(req->file, &apt.pt) & req->events; spin_lock_irq(&ctx->ctx_lock); - if (likely(req->head)) { - spin_lock(&req->head->lock); - if (unlikely(list_empty(&req->wait.entry))) { - if (apt.error) - cancel = true; - apt.error = 0; - mask = 0; - } - if (mask || apt.error) { - list_del_init(&req->wait.entry); - } else if (cancel) { - WRITE_ONCE(req->cancelled, true); - } else if (!req->done) { /* actually waiting for an event */ - list_add_tail(&aiocb->ki_list, &ctx->active_reqs); - aiocb->ki_cancel = aio_poll_cancel; - } - spin_unlock(&req->head->lock); + if (unlikely(!req->head)) + goto out; + spin_lock(&req->head->lock); + if (unlikely(list_empty(&req->wait.entry))) { + if (apt.error) + cancel = true; + apt.error = 0; + mask = 0; + } + if (mask || apt.error) { + list_del_init(&req->wait.entry); + } else if (cancel) { + WRITE_ONCE(req->cancelled, true); + } else if (!req->done) { /* actually waiting for an event */ + list_add_tail(&aiocb->ki_list, &ctx->active_reqs); + aiocb->ki_cancel = aio_poll_cancel; } + spin_unlock(&req->head->lock); +out: if (mask) { /* no async, we'd stolen it */ aiocb->ki_res.res = mangle_poll(mask); apt.error = 0; @@ -2058,11 +2083,12 @@ static long do_io_getevents(aio_context_t ctx_id, struct kioctx *ioctx = lookup_ioctx(ctx_id); long ret = -EINVAL; - if (likely(ioctx)) { - if (likely(min_nr <= nr && min_nr >= 0)) - ret = read_events(ioctx, min_nr, nr, events, until); - percpu_ref_put(&ioctx->users); - } + if (unlikely(!ioctx)) + return -EINVAL; + + if (likely(min_nr <= nr && min_nr >= 0)) + ret = read_events(ioctx, min_nr, nr, events, until); + percpu_ref_put(&ioctx->users); return ret; } -- 2.28.0