Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934187AbWKTOXR (ORCPT ); Mon, 20 Nov 2006 09:23:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934186AbWKTOXQ (ORCPT ); Mon, 20 Nov 2006 09:23:16 -0500 Received: from ecfrec.frec.bull.fr ([129.183.4.8]:2515 "EHLO ecfrec.frec.bull.fr") by vger.kernel.org with ESMTP id S934185AbWKTOXM convert rfc822-to-8bit (ORCPT ); Mon, 20 Nov 2006 09:23:12 -0500 Date: Mon, 20 Nov 2006 15:23:07 +0100 From: =?ISO-8859-1?Q?S=E9bastien_Dugu=E9?= To: linux-kernel Cc: linux-aio , Andrew Morton , Suparna Bhattacharya , Christoph Hellwig , Zach Brown , Badari Pulavarty , Jean Pierre Dion , Ulrich Drepper Subject: Re: [PATCH -mm 4/4][AIO] - Listio support Message-ID: <20061120152307.46dbf409@frecb000686> In-Reply-To: <20061120151700.4a4f9407@frecb000686> References: <20061120151700.4a4f9407@frecb000686> X-Mailer: Sylpheed-Claws 2.6.0 (GTK+ 2.8.20; i486-pc-linux-gnu) Mime-Version: 1.0 X-MIMETrack: Itemize by SMTP Server on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 20/11/2006 15:30:09, Serialize by Router on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 20/11/2006 15:30:12, Serialize complete at 20/11/2006 15:30:12 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9219 Lines: 318 POSIX listio support This patch adds POSIX listio completion notification support. It builds on support provided by the aio signal notification patch and adds an IOCB_CMD_GROUP command to io_submit(). The purpose of IOCB_CMD_GROUP is to group together the following requests in the list up to the end of the list sumbitted to io_submit. As io_submit already accepts an array of iocbs, as part of listio submission, the user process prepends to a list of requests an empty special aiocb with an aio_lio_opcode of IOCB_CMD_GROUP, filling only the aio_sigevent fields. An IOCB_CMD_GROUP is added to the IOCB_CMD enum in include/linux/aio_abi.h A struct lio_event is added in include/linux/aio.h A struct lio_event *ki_lio is added to struct iocb in include/linux/aio.h In io_submit(), upon detecting such an IOCB_CMD_GROUP marker iocb, an lio_event is created in lio_create() which contains the necessary information for signaling a thread (signal number, pid, notify type and value) along with a count of requests attached to this event. The following depicts the lio_event structure: struct lio_event { atomic_t lio_users; struct aio_notify lio_notify; }; lio_users holds an atomic counter of the number of requests attached to this lio. It is incremented with each request submitted and decremented at each request completion. When the counter reaches 0, we send the notification. Each subsequent submitted request is attached to this lio_event by setting the request kiocb->ki_lio to that lio_event (in io_submit_one()) and incrementing the lio_users count. In aio_complete(), if the request is attached to an lio (ki_lio <> 0), then lio_check() is called to decrement the lio_users count and eventually signal the user process when all the requests in the group have completed. The IOCB_CMD_GROUP semantic is as follows: - if the associated sigevent is NULL then we want to group requests for the purpose of blocking on the group completion (LIO_WAIT sync behavior). - if the associated sigevent is valid (not NULL) then we want to group requests for the purpose of being notified upon that group of requests completion (LIO_NOWAIT async behaviour). fs/aio.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++-- include/linux/aio.h | 13 ++++- include/linux/aio_abi.h | 1 3 files changed, 131 insertions(+), 6 deletions(-) Signed-off-by: S?bastien Dugu? Signed-off-by: Laurent Vivier Index: linux-2.6.19-rc5-mm2/fs/aio.c =================================================================== --- linux-2.6.19-rc5-mm2.orig/fs/aio.c 2006-11-17 11:20:32.000000000 +0100 +++ linux-2.6.19-rc5-mm2/fs/aio.c 2006-11-17 16:22:00.000000000 +0100 @@ -414,6 +414,7 @@ static struct kiocb fastcall *__aio_get_ req->ki_cancel = NULL; req->ki_retry = NULL; req->ki_dtor = NULL; + req->ki_lio = NULL; req->private = NULL; req->ki_iovec = NULL; req->ki_notify.sigq = NULL; @@ -1010,6 +1011,53 @@ out_unlock: return -EINVAL; } +static inline void lio_check(struct lio_event *lio) +{ + int ret; + + ret = atomic_dec_and_test(&lio->lio_users); + + if (unlikely(ret) && lio->lio_notify.notify != SIGEV_NONE) { + /* last one -> notify process */ + aio_send_signal(&lio->lio_notify); + kfree(lio); + } +} + +static struct lio_event *lio_create(struct sigevent __user *user_event) +{ + int ret = 0; + struct lio_event *lio = NULL; + + lio = kzalloc(sizeof(*lio), GFP_KERNEL); + + if (!lio) + return ERR_PTR(-EAGAIN); + + /* + * Grab an initial ref on the lio to avoid races between + * submission and completion. + */ + atomic_set(&lio->lio_users, 1); + + lio->lio_notify.notify = SIGEV_NONE; + + if (user_event) { + /* + * User specified an event for this lio, + * he wants to be notified upon lio completion. + */ + ret = aio_setup_sigevent(&lio->lio_notify, user_event); + + if (ret) { + kfree(lio); + return ERR_PTR(ret); + } + } + + return lio; +} + /* aio_complete * Called when the io request on the given iocb is complete. * Returns true if this is the last user of the request. The @@ -1058,8 +1106,12 @@ int fastcall aio_complete(struct kiocb * * when the event got cancelled. */ if (kiocbIsCancelled(iocb)) { + if (iocb->ki_lio) + lio_check(iocb->ki_lio); + if (iocb->ki_notify.sigq) sigqueue_free(iocb->ki_notify.sigq); + goto put_rq; } @@ -1100,6 +1152,9 @@ int fastcall aio_complete(struct kiocb * sigqueue_free(iocb->ki_notify.sigq); } + if (iocb->ki_lio) + lio_check(iocb->ki_lio); + pr_debug("%ld retries: %zd of %zd\n", iocb->ki_retried, iocb->ki_nbytes - iocb->ki_left, iocb->ki_nbytes); put_rq: @@ -1634,7 +1689,7 @@ static int aio_wake_function(wait_queue_ } int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, - struct iocb *iocb) + struct iocb *iocb, struct lio_event *lio) { struct kiocb *req; struct file *file; @@ -1696,6 +1751,9 @@ int fastcall io_submit_one(struct kioctx goto out_put_req; } + /* Attach this iocb to its lio */ + req->ki_lio = lio; + ret = aio_setup_iocb(req); if (ret) @@ -1739,6 +1797,8 @@ asmlinkage long sys_io_submit(aio_contex struct iocb __user * __user *iocbpp) { struct kioctx *ctx; + struct lio_event *lio = NULL; + int lio_wait = 0; long ret = 0; int i; @@ -1772,11 +1832,66 @@ asmlinkage long sys_io_submit(aio_contex break; } - ret = io_submit_one(ctx, user_iocb, &tmp); - if (ret) - break; + if (tmp.aio_lio_opcode == IOCB_CMD_GROUP) { + + /* this command means that all following IO commands + * are in the same group. + * + * Userspace either wants to be notified upon or block until + * completion of all the requests in the group. + */ + /* + * Ignore an IOCB_CMD_GROUP request if we are already + * processing one. This means only one listio per + * io_submit call. + */ + if (lio) + continue; + + lio = lio_create((struct sigevent __user *)(unsigned long) + tmp.aio_sigeventp); + + ret = PTR_ERR(lio); + + if (IS_ERR(lio)) + goto out_put_ctx; + + if (!tmp.aio_sigeventp) + lio_wait = 1; + } else { + if (lio) + atomic_inc(&lio->lio_users); + + ret = io_submit_one(ctx, user_iocb, &tmp, lio); + + if (ret) { + if (lio) { + /* + * If a request failed, just decrement + * the users count, but go on submitting + * subsequent requests. + */ + atomic_dec(&lio->lio_users); + } else + break; + } + } + } + + if (lio) { + /* + * Drop extra ref on the lio now that we're done submitting + * requests + */ + lio_check(lio); + + if (lio_wait) { + wait_event(ctx->wait, atomic_read(&lio->lio_users)==0); + kfree(lio); + } } +out_put_ctx: put_ioctx(ctx); return i ? i : ret; } Index: linux-2.6.19-rc5-mm2/include/linux/aio_abi.h =================================================================== --- linux-2.6.19-rc5-mm2.orig/include/linux/aio_abi.h 2006-11-17 11:20:32.000000000 +0100 +++ linux-2.6.19-rc5-mm2/include/linux/aio_abi.h 2006-11-17 11:21:31.000000000 +0100 @@ -43,6 +43,7 @@ enum { IOCB_CMD_NOOP = 6, IOCB_CMD_PREADV = 7, IOCB_CMD_PWRITEV = 8, + IOCB_CMD_GROUP = 9, }; /* read() from /dev/aio returns these structures. */ Index: linux-2.6.19-rc5-mm2/include/linux/aio.h =================================================================== --- linux-2.6.19-rc5-mm2.orig/include/linux/aio.h 2006-11-17 11:20:32.000000000 +0100 +++ linux-2.6.19-rc5-mm2/include/linux/aio.h 2006-11-17 11:21:31.000000000 +0100 @@ -58,6 +58,11 @@ struct aio_notify { struct sigqueue *sigq; }; +struct lio_event { + atomic_t lio_users; + struct aio_notify lio_notify; +}; + /* is there a better place to document function pointer methods? */ /** * ki_retry - iocb forward progress callback @@ -113,6 +118,9 @@ struct kiocb { wait_queue_t ki_wait; loff_t ki_pos; + /* lio this iocb might be attached to */ + struct lio_event *ki_lio; + void *private; /* State that we remember to be able to restart/retry */ unsigned short ki_opcode; @@ -220,12 +228,13 @@ struct mm_struct; extern void FASTCALL(exit_aio(struct mm_struct *mm)); extern struct kioctx *lookup_ioctx(unsigned long ctx_id); extern int FASTCALL(io_submit_one(struct kioctx *ctx, - struct iocb __user *user_iocb, struct iocb *iocb)); + struct iocb __user *user_iocb, struct iocb *iocb, + struct lio_event *lio)); /* semi private, but used by the 32bit emulations: */ struct kioctx *lookup_ioctx(unsigned long ctx_id); int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, - struct iocb *iocb)); + struct iocb *iocb, struct lio_event *lio)); #define get_ioctx(kioctx) do { \ BUG_ON(atomic_read(&(kioctx)->users) <= 0); \ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/