From patchwork Thu Sep 20 21:18:40 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Long Li X-Patchwork-Id: 10608777 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 655E515A6 for ; Thu, 20 Sep 2018 21:20:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 54A6D2E096 for ; Thu, 20 Sep 2018 21:20:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 495352E0B5; Thu, 20 Sep 2018 21:20:21 +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,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham 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 799EA2E096 for ; Thu, 20 Sep 2018 21:20:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388630AbeIUDF3 (ORCPT ); Thu, 20 Sep 2018 23:05:29 -0400 Received: from a2nlsmtp01-03.prod.iad2.secureserver.net ([198.71.225.37]:60442 "EHLO a2nlsmtp01-03.prod.iad2.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726128AbeIUDF3 (ORCPT ); Thu, 20 Sep 2018 23:05:29 -0400 Received: from linuxonhyperv2.linuxonhyperv.com ([107.180.71.197]) by : HOSTING RELAY : with ESMTP id 36LkgmcunwkZt36LkgKqwN; Thu, 20 Sep 2018 14:19:00 -0700 x-originating-ip: 107.180.71.197 Received: from longli by linuxonhyperv2.linuxonhyperv.com with local (Exim 4.91) (envelope-from ) id 1g36Lk-0003ay-M9; Thu, 20 Sep 2018 14:19:00 -0700 From: Long Li To: Steve French , linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org Cc: Long Li Subject: [PATCH V3 (resend) 3/7] CIFS: Add support for direct I/O read Date: Thu, 20 Sep 2018 21:18:40 +0000 Message-Id: <20180920211842.13721-3-longli@linuxonhyperv.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180920211842.13721-1-longli@linuxonhyperv.com> References: <20180920211842.13721-1-longli@linuxonhyperv.com> Reply-To: longli@microsoft.com X-CMAE-Envelope: MS4wfPrcekpaFGtM1V+r/8hOchv1+N+qDLk30c1D//ntpVams2oRUGkf5cDo2gHoogNuc+/8hihseOHsbjO6pJRSOjuNpfysaSb4zpZqqBriMgSWQ281I4qa 5nc1g2/EQaVhQFGq7PG8OSQGjFZsvZr5dxYMsqa+8KziIMXHBomknzKNy+c9F3HWaUX/VVaexUm5nZdhjeRgIWIqJCgum5AXXbyTwrzM/QVhnr/HVsDlpYot LZ6LqHZJQ+TbK58WScd2mwMSZKzBjRTe7V5QwcvutWK7Gc11tC9R6is7R1n8TxyRM6VAYfGCkDJ9MgfvBXDmAGuujn5o0IXVrHQ6lmd0edB2WQlnPY2Ae/tt QjHUZai0lWDFbM9EXV18F65BQpIk33xt7AjUZKpvG7HtxC2RTfIUprVZtrmwh0NgC2S+L90p Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Long Li With direct I/O read, we transfer the data directly from transport layer to the user data buffer. Change in v3: add support for kernel AIO Signed-off-by: Long Li --- fs/cifs/cifsfs.h | 1 + fs/cifs/cifsglob.h | 5 ++ fs/cifs/file.c | 210 +++++++++++++++++++++++++++++++++++++++++++++-------- 3 files changed, 187 insertions(+), 29 deletions(-) diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h index f047e87..ed5479c 100644 --- a/fs/cifs/cifsfs.h +++ b/fs/cifs/cifsfs.h @@ -101,6 +101,7 @@ extern int cifs_open(struct inode *inode, struct file *file); extern int cifs_close(struct inode *inode, struct file *file); extern int cifs_closedir(struct inode *inode, struct file *file); extern ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to); +extern ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter *to); extern ssize_t cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to); extern ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from); extern ssize_t cifs_strict_writev(struct kiocb *iocb, struct iov_iter *from); diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index 9dcaed0..2131fec 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -1172,6 +1172,11 @@ struct cifs_aio_ctx { unsigned int len; unsigned int total_len; bool should_dirty; + /* + * Indicates if this aio_ctx is for direct_io, + * If yes, iter is a copy of the user passed iov_iter + */ + bool direct_io; }; struct cifs_readdata; diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 8d41ca7..6a939fa 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -2965,7 +2965,6 @@ cifs_uncached_readdata_release(struct kref *refcount) kref_put(&rdata->ctx->refcount, cifs_aio_ctx_release); for (i = 0; i < rdata->nr_pages; i++) { put_page(rdata->pages[i]); - rdata->pages[i] = NULL; } cifs_readdata_release(refcount); } @@ -3004,7 +3003,7 @@ cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter) return remaining ? -EFAULT : 0; } -static void collect_uncached_read_data(struct cifs_aio_ctx *ctx); +static void collect_uncached_read_data(struct cifs_readdata *rdata, struct cifs_aio_ctx *ctx); static void cifs_uncached_readv_complete(struct work_struct *work) @@ -3013,7 +3012,7 @@ cifs_uncached_readv_complete(struct work_struct *work) struct cifs_readdata, work); complete(&rdata->done); - collect_uncached_read_data(rdata->ctx); + collect_uncached_read_data(rdata, rdata->ctx); /* the below call can possibly free the last ref to aio ctx */ kref_put(&rdata->refcount, cifs_uncached_readdata_release); } @@ -3103,6 +3102,9 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, int rc; pid_t pid; struct TCP_Server_Info *server; + struct page **pagevec; + size_t start; + struct iov_iter direct_iov = ctx->iter; server = tlink_tcon(open_file->tlink)->ses->server; @@ -3111,6 +3113,9 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, else pid = current->tgid; + if (ctx->direct_io) + iov_iter_advance(&direct_iov, offset - ctx->pos); + do { rc = server->ops->wait_mtu_credits(server, cifs_sb->rsize, &rsize, &credits); @@ -3118,20 +3123,56 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, break; cur_len = min_t(const size_t, len, rsize); - npages = DIV_ROUND_UP(cur_len, PAGE_SIZE); - /* allocate a readdata struct */ - rdata = cifs_readdata_alloc(npages, + if (ctx->direct_io) { + + cur_len = iov_iter_get_pages_alloc( + &direct_iov, &pagevec, + cur_len, &start); + if (cur_len < 0) { + cifs_dbg(VFS, + "couldn't get user pages (cur_len=%zd)" + " iter type %d" + " iov_offset %zd count %zd\n", + cur_len, direct_iov.type, direct_iov.iov_offset, + direct_iov.count); + dump_stack(); + break; + } + iov_iter_advance(&direct_iov, cur_len); + + rdata = cifs_readdata_direct_alloc( + pagevec, cifs_uncached_readv_complete); + if (!rdata) { + add_credits_and_wake_if(server, credits, 0); + rc = -ENOMEM; + break; + } + + npages = (cur_len + start + PAGE_SIZE-1) / PAGE_SIZE; + rdata->page_offset = start; + rdata->tailsz = npages > 1 ? + cur_len-(PAGE_SIZE-start)-(npages-2)*PAGE_SIZE : + cur_len; + + } else { + + npages = DIV_ROUND_UP(cur_len, PAGE_SIZE); + /* allocate a readdata struct */ + rdata = cifs_readdata_alloc(npages, cifs_uncached_readv_complete); - if (!rdata) { - add_credits_and_wake_if(server, credits, 0); - rc = -ENOMEM; - break; - } + if (!rdata) { + add_credits_and_wake_if(server, credits, 0); + rc = -ENOMEM; + break; + } - rc = cifs_read_allocate_pages(rdata, npages); - if (rc) - goto error; + rc = cifs_read_allocate_pages(rdata, npages); + if (rc) + goto error; + + rdata->tailsz = PAGE_SIZE; + } rdata->cfile = cifsFileInfo_get(open_file); rdata->nr_pages = npages; @@ -3139,7 +3180,6 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, rdata->bytes = cur_len; rdata->pid = pid; rdata->pagesz = PAGE_SIZE; - rdata->tailsz = PAGE_SIZE; rdata->read_into_pages = cifs_uncached_read_into_pages; rdata->copy_into_pages = cifs_uncached_copy_into_pages; rdata->credits = credits; @@ -3153,13 +3193,17 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, if (rc) { add_credits_and_wake_if(server, rdata->credits, 0); kref_put(&rdata->refcount, - cifs_uncached_readdata_release); - if (rc == -EAGAIN) + cifs_uncached_readdata_release); + if (rc == -EAGAIN) { + iov_iter_revert(&direct_iov, cur_len); continue; + } break; } - list_add_tail(&rdata->list, rdata_list); + /* Add to aio pending list if it's not there */ + if (rdata_list) + list_add_tail(&rdata->list, rdata_list); offset += cur_len; len -= cur_len; } while (len > 0); @@ -3168,7 +3212,7 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, } static void -collect_uncached_read_data(struct cifs_aio_ctx *ctx) +collect_uncached_read_data(struct cifs_readdata *uncached_rdata, struct cifs_aio_ctx *ctx) { struct cifs_readdata *rdata, *tmp; struct iov_iter *to = &ctx->iter; @@ -3211,10 +3255,12 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) * reading. */ if (got_bytes && got_bytes < rdata->bytes) { - rc = cifs_readdata_to_iov(rdata, to); + rc = 0; + if (!ctx->direct_io) + rc = cifs_readdata_to_iov(rdata, to); if (rc) { kref_put(&rdata->refcount, - cifs_uncached_readdata_release); + cifs_uncached_readdata_release); continue; } } @@ -3228,28 +3274,32 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) list_splice(&tmp_list, &ctx->list); kref_put(&rdata->refcount, - cifs_uncached_readdata_release); + cifs_uncached_readdata_release); goto again; } else if (rdata->result) rc = rdata->result; - else + else if (!ctx->direct_io) rc = cifs_readdata_to_iov(rdata, to); /* if there was a short read -- discard anything left */ if (rdata->got_bytes && rdata->got_bytes < rdata->bytes) rc = -ENODATA; + + ctx->total_len += rdata->got_bytes; } list_del_init(&rdata->list); kref_put(&rdata->refcount, cifs_uncached_readdata_release); } - for (i = 0; i < ctx->npages; i++) { - if (ctx->should_dirty) - set_page_dirty(ctx->bv[i].bv_page); - put_page(ctx->bv[i].bv_page); - } + if (!ctx->direct_io) { + for (i = 0; i < ctx->npages; i++) { + if (ctx->should_dirty) + set_page_dirty(ctx->bv[i].bv_page); + put_page(ctx->bv[i].bv_page); + } - ctx->total_len = ctx->len - iov_iter_count(to); + ctx->total_len = ctx->len - iov_iter_count(to); + } cifs_stats_bytes_read(tcon, ctx->total_len); @@ -3267,6 +3317,108 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) complete(&ctx->done); } +ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter *to) +{ + size_t len; + struct file *file; + struct cifs_sb_info *cifs_sb; + struct cifsFileInfo *cfile; + struct cifs_tcon *tcon; + ssize_t rc, total_read = 0; + struct TCP_Server_Info *server; + loff_t offset = iocb->ki_pos; + pid_t pid; + struct cifs_aio_ctx *ctx; + + /* + * iov_iter_get_pages_alloc() doesn't work with ITER_KVEC, + * fall back to data copy read path + * this could be improved by getting pages directly in ITER_KVEC + */ + if (to->type & ITER_KVEC) { + cifs_dbg(FYI, "use non-direct cifs_user_readv for kvec I/O\n"); + return cifs_user_readv(iocb, to); + } + + len = iov_iter_count(to); + if (!len) + return 0; + + file = iocb->ki_filp; + cifs_sb = CIFS_FILE_SB(file); + cfile = file->private_data; + tcon = tlink_tcon(cfile->tlink); + server = tcon->ses->server; + + if (!server->ops->async_readv) + return -ENOSYS; + + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD) + pid = cfile->pid; + else + pid = current->tgid; + + if ((file->f_flags & O_ACCMODE) == O_WRONLY) + cifs_dbg(FYI, "attempting read on write only file instance\n"); + + ctx = cifs_aio_ctx_alloc(); + if (!ctx) + return -ENOMEM; + + ctx->cfile = cifsFileInfo_get(cfile); + + if (!is_sync_kiocb(iocb)) + ctx->iocb = iocb; + + if (to->type == ITER_IOVEC) + ctx->should_dirty = true; + + ctx->pos = offset; + ctx->direct_io = true; + ctx->iter = *to; + ctx->len = len; + + /* grab a lock here due to read response handlers can access ctx */ + mutex_lock(&ctx->aio_mutex); + + rc = cifs_send_async_read(offset, len, cfile, cifs_sb, &ctx->list, ctx); + + /* if at least one read request send succeeded, then reset rc */ + if (!list_empty(&ctx->list)) + rc = 0; + + mutex_unlock(&ctx->aio_mutex); + + if (rc) { + kref_put(&ctx->refcount, cifs_aio_ctx_release); + return rc; + } + + if (!is_sync_kiocb(iocb)) { + kref_put(&ctx->refcount, cifs_aio_ctx_release); + return -EIOCBQUEUED; + } + + rc = wait_for_completion_killable(&ctx->done); + if (rc) { + mutex_lock(&ctx->aio_mutex); + ctx->rc = rc = -EINTR; + total_read = ctx->total_len; + mutex_unlock(&ctx->aio_mutex); + } else { + rc = ctx->rc; + total_read = ctx->total_len; + } + + kref_put(&ctx->refcount, cifs_aio_ctx_release); + + if (total_read) { + iocb->ki_pos += total_read; + return total_read; + } + return rc; +} + ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to) { struct file *file = iocb->ki_filp;