From: Christoph Hellwig <hch@lst.de> To: viro@zeniv.linux.org.uk Cc: Avi Kivity <avi@scylladb.com>, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 07/36] aio: add delayed cancel support Date: Mon, 5 Mar 2018 13:27:14 -0800 [thread overview] Message-ID: <20180305212743.16664-8-hch@lst.de> (raw) In-Reply-To: <20180305212743.16664-1-hch@lst.de> The upcoming aio poll support would like to be able to complete the iocb inline from the cancellation context, but that would cause a lock order reversal. Add support for optionally moving the cancelation outside the context lock to avoid this reversal. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Jeff Moyer <jmoyer@redhat.com> --- fs/aio.c | 49 ++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 38 insertions(+), 11 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 0b6394b4e528..9d7d6e4cde87 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -170,6 +170,10 @@ struct aio_kiocb { struct list_head ki_list; /* the aio core uses this * for cancellation */ + unsigned int flags; /* protected by ctx->ctx_lock */ +#define AIO_IOCB_DELAYED_CANCEL (1 << 0) +#define AIO_IOCB_CANCELLED (1 << 1) + /* * If the aio_resfd field of the userspace iocb is not zero, * this is the underlying eventfd context to deliver events to. @@ -536,9 +540,9 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events) #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) -void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) +static void __kiocb_set_cancel_fn(struct aio_kiocb *req, + kiocb_cancel_fn *cancel, unsigned int iocb_flags) { - struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw); struct kioctx *ctx = req->ki_ctx; unsigned long flags; @@ -548,8 +552,15 @@ void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) spin_lock_irqsave(&ctx->ctx_lock, flags); list_add_tail(&req->ki_list, &ctx->active_reqs); req->ki_cancel = cancel; + req->flags |= iocb_flags; spin_unlock_irqrestore(&ctx->ctx_lock, flags); } + +void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) +{ + return __kiocb_set_cancel_fn(container_of(iocb, struct aio_kiocb, rw), + cancel, 0); +} EXPORT_SYMBOL(kiocb_set_cancel_fn); /* @@ -603,17 +614,27 @@ static void free_ioctx_users(struct percpu_ref *ref) { struct kioctx *ctx = container_of(ref, struct kioctx, users); struct aio_kiocb *req; + LIST_HEAD(list); spin_lock_irq(&ctx->ctx_lock); - while (!list_empty(&ctx->active_reqs)) { req = list_first_entry(&ctx->active_reqs, struct aio_kiocb, ki_list); - kiocb_cancel(req); - } + if (req->flags & AIO_IOCB_DELAYED_CANCEL) { + req->flags |= AIO_IOCB_CANCELLED; + list_move_tail(&req->ki_list, &list); + } else { + kiocb_cancel(req); + } + } spin_unlock_irq(&ctx->ctx_lock); + while (!list_empty(&list)) { + req = list_first_entry(&list, struct aio_kiocb, ki_list); + kiocb_cancel(req); + } + percpu_ref_kill(&ctx->reqs); percpu_ref_put(&ctx->reqs); } @@ -1785,15 +1806,22 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, if (unlikely(!ctx)) return -EINVAL; - spin_lock_irq(&ctx->ctx_lock); + ret = -EINVAL; + spin_lock_irq(&ctx->ctx_lock); kiocb = lookup_kiocb(ctx, iocb, key); + if (kiocb) { + if (kiocb->flags & AIO_IOCB_DELAYED_CANCEL) { + kiocb->flags |= AIO_IOCB_CANCELLED; + } else { + ret = kiocb_cancel(kiocb); + kiocb = NULL; + } + } + spin_unlock_irq(&ctx->ctx_lock); + if (kiocb) ret = kiocb_cancel(kiocb); - else - ret = -EINVAL; - - spin_unlock_irq(&ctx->ctx_lock); if (!ret) { /* @@ -1805,7 +1833,6 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, } percpu_ref_put(&ctx->users); - return ret; } -- 2.14.2
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de> To: viro@zeniv.linux.org.uk Cc: Avi Kivity <avi@scylladb.com>, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 07/36] aio: add delayed cancel support Date: Mon, 5 Mar 2018 13:27:14 -0800 [thread overview] Message-ID: <20180305212743.16664-8-hch@lst.de> (raw) In-Reply-To: <20180305212743.16664-1-hch@lst.de> The upcoming aio poll support would like to be able to complete the iocb inline from the cancellation context, but that would cause a lock order reversal. Add support for optionally moving the cancelation outside the context lock to avoid this reversal. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Jeff Moyer <jmoyer@redhat.com> --- fs/aio.c | 49 ++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 38 insertions(+), 11 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 0b6394b4e528..9d7d6e4cde87 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -170,6 +170,10 @@ struct aio_kiocb { struct list_head ki_list; /* the aio core uses this * for cancellation */ + unsigned int flags; /* protected by ctx->ctx_lock */ +#define AIO_IOCB_DELAYED_CANCEL (1 << 0) +#define AIO_IOCB_CANCELLED (1 << 1) + /* * If the aio_resfd field of the userspace iocb is not zero, * this is the underlying eventfd context to deliver events to. @@ -536,9 +540,9 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events) #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) -void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) +static void __kiocb_set_cancel_fn(struct aio_kiocb *req, + kiocb_cancel_fn *cancel, unsigned int iocb_flags) { - struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw); struct kioctx *ctx = req->ki_ctx; unsigned long flags; @@ -548,8 +552,15 @@ void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) spin_lock_irqsave(&ctx->ctx_lock, flags); list_add_tail(&req->ki_list, &ctx->active_reqs); req->ki_cancel = cancel; + req->flags |= iocb_flags; spin_unlock_irqrestore(&ctx->ctx_lock, flags); } + +void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) +{ + return __kiocb_set_cancel_fn(container_of(iocb, struct aio_kiocb, rw), + cancel, 0); +} EXPORT_SYMBOL(kiocb_set_cancel_fn); /* @@ -603,17 +614,27 @@ static void free_ioctx_users(struct percpu_ref *ref) { struct kioctx *ctx = container_of(ref, struct kioctx, users); struct aio_kiocb *req; + LIST_HEAD(list); spin_lock_irq(&ctx->ctx_lock); - while (!list_empty(&ctx->active_reqs)) { req = list_first_entry(&ctx->active_reqs, struct aio_kiocb, ki_list); - kiocb_cancel(req); - } + if (req->flags & AIO_IOCB_DELAYED_CANCEL) { + req->flags |= AIO_IOCB_CANCELLED; + list_move_tail(&req->ki_list, &list); + } else { + kiocb_cancel(req); + } + } spin_unlock_irq(&ctx->ctx_lock); + while (!list_empty(&list)) { + req = list_first_entry(&list, struct aio_kiocb, ki_list); + kiocb_cancel(req); + } + percpu_ref_kill(&ctx->reqs); percpu_ref_put(&ctx->reqs); } @@ -1785,15 +1806,22 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, if (unlikely(!ctx)) return -EINVAL; - spin_lock_irq(&ctx->ctx_lock); + ret = -EINVAL; + spin_lock_irq(&ctx->ctx_lock); kiocb = lookup_kiocb(ctx, iocb, key); + if (kiocb) { + if (kiocb->flags & AIO_IOCB_DELAYED_CANCEL) { + kiocb->flags |= AIO_IOCB_CANCELLED; + } else { + ret = kiocb_cancel(kiocb); + kiocb = NULL; + } + } + spin_unlock_irq(&ctx->ctx_lock); + if (kiocb) ret = kiocb_cancel(kiocb); - else - ret = -EINVAL; - - spin_unlock_irq(&ctx->ctx_lock); if (!ret) { /* @@ -1805,7 +1833,6 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, } percpu_ref_put(&ctx->users); - return ret; } -- 2.14.2 -- To unsubscribe, send a message with 'unsubscribe linux-aio' in the body to majordomo@kvack.org. For more info on Linux AIO, see: http://www.kvack.org/aio/ Don't email: <a href=mailto:"aart@kvack.org">aart@kvack.org</a>
next prev parent reply other threads:[~2018-03-05 21:43 UTC|newest] Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-03-05 21:27 aio poll, io_pgetevents and a new in-kernel poll API V5 Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 01/36] aio: don't print the page size at boot time Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-20 0:11 ` Darrick J. Wong 2018-03-20 0:11 ` Darrick J. Wong 2018-03-05 21:27 ` [PATCH 02/36] aio: remove an outdated comment in aio_complete Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-20 0:12 ` Darrick J. Wong 2018-03-20 0:12 ` Darrick J. Wong 2018-03-05 21:27 ` [PATCH 03/36] aio: refactor read/write iocb setup Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-20 0:19 ` Darrick J. Wong 2018-03-20 0:19 ` Darrick J. Wong 2018-03-05 21:27 ` [PATCH 04/36] aio: sanitize ki_list handling Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-20 0:21 ` Darrick J. Wong 2018-03-20 0:21 ` Darrick J. Wong 2018-03-05 21:27 ` [PATCH 05/36] aio: simplify cancellation Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-20 0:25 ` Darrick J. Wong 2018-03-20 0:25 ` Darrick J. Wong 2018-03-05 21:27 ` [PATCH 06/36] aio: delete iocbs from the active_reqs list in kiocb_cancel Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-20 0:34 ` Darrick J. Wong 2018-03-20 0:34 ` Darrick J. Wong 2018-03-05 21:27 ` Christoph Hellwig [this message] 2018-03-05 21:27 ` [PATCH 07/36] aio: add delayed cancel support Christoph Hellwig 2018-03-20 3:19 ` Darrick J. Wong 2018-03-20 3:19 ` Darrick J. Wong 2018-03-20 15:20 ` Christoph Hellwig 2018-03-20 15:20 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 08/36] aio: implement io_pgetevents Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:51 ` Jeff Moyer 2018-03-05 21:51 ` Jeff Moyer 2018-03-05 21:51 ` Jeff Moyer 2018-03-20 2:12 ` Darrick J. Wong 2018-03-20 2:12 ` Darrick J. Wong 2018-03-20 15:22 ` Christoph Hellwig 2018-03-20 15:22 ` Christoph Hellwig 2018-03-20 15:30 ` Jeff Moyer 2018-03-20 15:30 ` Jeff Moyer 2018-03-20 15:30 ` Jeff Moyer 2018-03-20 15:31 ` Christoph Hellwig 2018-03-20 15:31 ` Christoph Hellwig 2018-03-20 15:34 ` Jeff Moyer 2018-03-20 15:34 ` Jeff Moyer 2018-03-20 15:34 ` Jeff Moyer 2018-03-05 21:27 ` [PATCH 09/36] fs: unexport poll_schedule_timeout Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-20 2:13 ` Darrick J. Wong 2018-03-20 2:13 ` Darrick J. Wong 2018-03-05 21:27 ` [PATCH 10/36] fs: cleanup do_pollfd Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-20 2:14 ` Darrick J. Wong 2018-03-20 2:14 ` Darrick J. Wong 2018-03-05 21:27 ` [PATCH 11/36] fs: update documentation for __poll_t Christoph Hellwig 2018-03-20 2:19 ` Darrick J. Wong 2018-03-20 2:19 ` Darrick J. Wong 2018-03-05 21:27 ` [PATCH 12/36] fs: add new vfs_poll and file_can_poll helpers Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-20 2:27 ` Darrick J. Wong 2018-03-20 2:27 ` Darrick J. Wong 2018-03-05 21:27 ` [PATCH 13/36] fs: introduce new ->get_poll_head and ->poll_mask methods Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-20 3:29 ` Darrick J. Wong 2018-03-20 3:29 ` Darrick J. Wong 2018-03-20 15:39 ` Christoph Hellwig 2018-03-20 15:39 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 14/36] aio: implement IOCB_CMD_POLL Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:51 ` Jeff Moyer 2018-03-05 21:27 ` [PATCH 15/36] net: refactor socket_poll Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 16/36] net: add support for ->poll_mask in proto_ops Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 17/36] net: remove sock_no_poll Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 18/36] net/tcp: convert to ->poll_mask Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 19/36] net/unix: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 20/36] net: convert datagram_poll users tp ->poll_mask Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 21/36] net/dccp: convert to ->poll_mask Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 22/36] net/atm: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 23/36] net/vmw_vsock: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 24/36] net/tipc: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 25/36] net/sctp: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 26/36] net/bluetooth: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 27/36] net/caif: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 28/36] net/nfc: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 29/36] net/phonet: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 30/36] net/iucv: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 31/36] net/rxrpc: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 32/36] crypto: af_alg: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 33/36] pipe: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 34/36] eventfd: switch " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 35/36] timerfd: convert " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-05 21:27 ` [PATCH 36/36] random: " Christoph Hellwig 2018-03-05 21:27 ` Christoph Hellwig 2018-03-13 7:46 ` aio poll, io_pgetevents and a new in-kernel poll API V5 Christoph Hellwig 2018-03-19 8:35 ` Christoph Hellwig 2018-03-19 8:35 ` Christoph Hellwig -- strict thread matches above, loose matches on Subject: below -- 2018-01-22 20:12 aio poll, io_pgetevents and a new in-kernel poll API V4 Christoph Hellwig 2018-01-22 20:12 ` [PATCH 07/36] aio: add delayed cancel support Christoph Hellwig 2018-01-22 20:12 ` Christoph Hellwig 2018-01-17 19:27 aio poll, io_pgetevents and a new in-kernel poll API V3 Christoph Hellwig 2018-01-17 19:27 ` [PATCH 07/36] aio: add delayed cancel support Christoph Hellwig 2018-01-17 19:27 ` Christoph Hellwig
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20180305212743.16664-8-hch@lst.de \ --to=hch@lst.de \ --cc=avi@scylladb.com \ --cc=linux-aio@kvack.org \ --cc=linux-api@vger.kernel.org \ --cc=linux-fsdevel@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=netdev@vger.kernel.org \ --cc=viro@zeniv.linux.org.uk \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.