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Registered in England and Wales under Company Registration No. 3798903 Subject: [RFC PATCH 6/7] cifs: Get direct I/O and unbuffered I/O working with iterators From: David Howells To: smfrench@gmail.com, nspmangalore@gmail.com Cc: dhowells@redhat.com, jlayton@kernel.org, linux-cifs@vger.kernel.org, linux-cachefs@redhat.com, linux-fsdevel@vger.kernel.org Date: Tue, 25 Jan 2022 13:58:53 +0000 Message-ID: <164311913303.2806745.13306912789898168904.stgit@warthog.procyon.org.uk> In-Reply-To: <164311902471.2806745.10187041199819525677.stgit@warthog.procyon.org.uk> References: <164311902471.2806745.10187041199819525677.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org --- fs/cifs/cifsproto.h | 1 fs/cifs/file.c | 299 ++++++--------------------------------------------- fs/cifs/misc.c | 90 --------------- 3 files changed, 35 insertions(+), 355 deletions(-) diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index 1b143f0a03c0..fb6bcda46266 100644 --- a/fs/cifs/cifsproto.h +++ b/fs/cifs/cifsproto.h @@ -595,7 +595,6 @@ enum securityEnum cifs_select_sectype(struct TCP_Server_Info *, enum securityEnum); struct cifs_aio_ctx *cifs_aio_ctx_alloc(void); void cifs_aio_ctx_release(struct kref *refcount); -int setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw); void smb2_cached_lease_break(struct work_struct *work); int cifs_alloc_hash(const char *name, struct crypto_shash **shash, diff --git a/fs/cifs/file.c b/fs/cifs/file.c index b57f9b492227..f9b9a1562e17 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -3321,6 +3321,9 @@ cifs_readdata_release(struct kref *refcount) { struct cifs_readdata *rdata = container_of(refcount, struct cifs_readdata, refcount); + + if (rdata->ctx) + kref_put(&rdata->ctx->refcount, cifs_aio_ctx_release); #ifdef CONFIG_CIFS_SMB_DIRECT if (rdata->mr) { smbd_deregister_mr(rdata->mr); @@ -3330,85 +3333,9 @@ cifs_readdata_release(struct kref *refcount) if (rdata->cfile) cifsFileInfo_put(rdata->cfile); - kvfree(rdata->pages); kfree(rdata); } -static int -cifs_read_allocate_pages(struct cifs_readdata *rdata, unsigned int nr_pages) -{ - int rc = 0; - struct page *page; - unsigned int i; - - for (i = 0; i < nr_pages; i++) { - page = alloc_page(GFP_KERNEL|__GFP_HIGHMEM); - if (!page) { - rc = -ENOMEM; - break; - } - rdata->pages[i] = page; - } - - if (rc) { - unsigned int nr_page_failed = i; - - for (i = 0; i < nr_page_failed; i++) { - put_page(rdata->pages[i]); - rdata->pages[i] = NULL; - } - } - return rc; -} - -static void -cifs_uncached_readdata_release(struct kref *refcount) -{ - struct cifs_readdata *rdata = container_of(refcount, - struct cifs_readdata, refcount); - unsigned int i; - - kref_put(&rdata->ctx->refcount, cifs_aio_ctx_release); - for (i = 0; i < rdata->nr_pages; i++) { - put_page(rdata->pages[i]); - } - cifs_readdata_release(refcount); -} - -/** - * cifs_readdata_to_iov - copy data from pages in response to an iovec - * @rdata: the readdata response with list of pages holding data - * @iter: destination for our data - * - * This function copies data from a list of pages in a readdata response into - * an array of iovecs. It will first calculate where the data should go - * based on the info in the readdata and then copy the data into that spot. - */ -static int -cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter) -{ - size_t remaining = rdata->got_bytes; - unsigned int i; - - for (i = 0; i < rdata->nr_pages; i++) { - struct page *page = rdata->pages[i]; - size_t copy = min_t(size_t, remaining, PAGE_SIZE); - size_t written; - - if (unlikely(iov_iter_is_pipe(iter))) { - void *addr = kmap_atomic(page); - - written = copy_to_iter(addr, copy, iter); - kunmap_atomic(addr); - } else - written = copy_page_to_iter(page, 0, copy, iter); - remaining -= written; - if (written < copy && iov_iter_count(iter) > 0) - break; - } - return remaining ? -EFAULT : 0; -} - static void collect_uncached_read_data(struct cifs_aio_ctx *ctx); static void @@ -3420,81 +3347,7 @@ cifs_uncached_readv_complete(struct work_struct *work) complete(&rdata->done); collect_uncached_read_data(rdata->ctx); /* the below call can possibly free the last ref to aio ctx */ - kref_put(&rdata->refcount, cifs_uncached_readdata_release); -} - -static int -uncached_fill_pages(struct TCP_Server_Info *server, - struct cifs_readdata *rdata, struct iov_iter *iter, - unsigned int len) -{ - int result = 0; - unsigned int i; - unsigned int nr_pages = rdata->nr_pages; - unsigned int page_offset = rdata->page_offset; - - rdata->got_bytes = 0; - rdata->tailsz = PAGE_SIZE; - for (i = 0; i < nr_pages; i++) { - struct page *page = rdata->pages[i]; - size_t n; - unsigned int segment_size = rdata->pagesz; - - if (i == 0) - segment_size -= page_offset; - else - page_offset = 0; - - - if (len <= 0) { - /* no need to hold page hostage */ - rdata->pages[i] = NULL; - rdata->nr_pages--; - put_page(page); - continue; - } - - n = len; - if (len >= segment_size) - /* enough data to fill the page */ - n = segment_size; - else - rdata->tailsz = len; - len -= n; - - if (iter) - result = copy_page_from_iter( - page, page_offset, n, iter); -#ifdef CONFIG_CIFS_SMB_DIRECT - else if (rdata->mr) - result = n; -#endif - else - result = cifs_read_page_from_socket( - server, page, page_offset, n); - if (result < 0) - break; - - rdata->got_bytes += result; - } - - return rdata->got_bytes > 0 && result != -ECONNABORTED ? - rdata->got_bytes : result; -} - -static int -cifs_uncached_read_into_pages(struct TCP_Server_Info *server, - struct cifs_readdata *rdata, unsigned int len) -{ - return uncached_fill_pages(server, rdata, NULL, len); -} - -static int -cifs_uncached_copy_into_pages(struct TCP_Server_Info *server, - struct cifs_readdata *rdata, - struct iov_iter *iter) -{ - return uncached_fill_pages(server, rdata, iter, iter->count); + kref_put(&rdata->refcount, cifs_readdata_release); } static int cifs_resend_rdata(struct cifs_readdata *rdata, @@ -3565,7 +3418,7 @@ static int cifs_resend_rdata(struct cifs_readdata *rdata, } while (rc == -EAGAIN); fail: - kref_put(&rdata->refcount, cifs_uncached_readdata_release); + kref_put(&rdata->refcount, cifs_readdata_release); return rc; } @@ -3575,16 +3428,13 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, struct cifs_aio_ctx *ctx) { struct cifs_readdata *rdata; - unsigned int npages, rsize; + unsigned int rsize; struct cifs_credits credits_on_stack; struct cifs_credits *credits = &credits_on_stack; size_t cur_len; int rc; pid_t pid; struct TCP_Server_Info *server; - struct page **pagevec; - size_t start; - struct iov_iter direct_iov = ctx->iter; server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses); @@ -3593,9 +3443,6 @@ 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 { if (open_file->invalidHandle) { rc = cifs_reopen_file(open_file, true); @@ -3612,77 +3459,26 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, cur_len = min_t(const size_t, len, rsize); - if (ctx->direct_io) { - ssize_t result; - - result = iov_iter_get_pages_alloc( - &direct_iov, &pagevec, - cur_len, &start); - if (result < 0) { - cifs_dbg(VFS, - "Couldn't get user pages (rc=%zd) iter type %d iov_offset %zd count %zd\n", - result, iov_iter_type(&direct_iov), - direct_iov.iov_offset, - direct_iov.count); - dump_stack(); - - rc = result; - add_credits_and_wake_if(server, credits, 0); - break; - } - cur_len = (size_t)result; - 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; - } - - rc = cifs_read_allocate_pages(rdata, npages); - if (rc) { - kvfree(rdata->pages); - kfree(rdata); - add_credits_and_wake_if(server, credits, 0); - break; - } - - rdata->tailsz = PAGE_SIZE; + rdata = cifs_readdata_alloc(cifs_uncached_readv_complete); + if (!rdata) { + add_credits_and_wake_if(server, credits, 0); + rc = -ENOMEM; + break; } - rdata->server = server; - rdata->cfile = cifsFileInfo_get(open_file); - rdata->nr_pages = npages; - rdata->offset = offset; - rdata->bytes = cur_len; - rdata->pid = pid; - rdata->pagesz = PAGE_SIZE; - rdata->read_into_pages = cifs_uncached_read_into_pages; - rdata->copy_into_pages = cifs_uncached_copy_into_pages; - rdata->credits = credits_on_stack; - rdata->ctx = ctx; + rdata->server = server; + rdata->cfile = cifsFileInfo_get(open_file); + rdata->offset = offset; + rdata->bytes = cur_len; + rdata->pid = pid; + rdata->credits = credits_on_stack; + rdata->ctx = ctx; kref_get(&ctx->refcount); + rdata->iter = ctx->iter; + iov_iter_advance(&rdata->iter, offset - ctx->pos); + iov_iter_truncate(&rdata->iter, cur_len); + rc = adjust_credits(server, &rdata->credits, rdata->bytes); if (!rc) { @@ -3694,12 +3490,9 @@ 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) { - iov_iter_revert(&direct_iov, cur_len); + kref_put(&rdata->refcount, cifs_readdata_release); + if (rc == -EAGAIN) continue; - } break; } @@ -3746,22 +3539,6 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) list_del_init(&rdata->list); INIT_LIST_HEAD(&tmp_list); - /* - * Got a part of data and then reconnect has - * happened -- fill the buffer and continue - * reading. - */ - if (got_bytes && got_bytes < rdata->bytes) { - rc = 0; - if (!ctx->direct_io) - rc = cifs_readdata_to_iov(rdata, to); - if (rc) { - kref_put(&rdata->refcount, - cifs_uncached_readdata_release); - continue; - } - } - if (ctx->direct_io) { /* * Re-use rdata as this is a @@ -3778,7 +3555,7 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) &tmp_list, ctx); kref_put(&rdata->refcount, - cifs_uncached_readdata_release); + cifs_readdata_release); } list_splice(&tmp_list, &ctx->list); @@ -3786,8 +3563,6 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) goto again; } else if (rdata->result) rc = rdata->result; - 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) @@ -3796,7 +3571,7 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) ctx->total_len += rdata->got_bytes; } list_del_init(&rdata->list); - kref_put(&rdata->refcount, cifs_uncached_readdata_release); + kref_put(&rdata->refcount, cifs_readdata_release); } if (!ctx->direct_io) @@ -3856,7 +3631,10 @@ static ssize_t __cifs_readv( if (!ctx) return -ENOMEM; - ctx->cfile = cifsFileInfo_get(cfile); + ctx->pos = offset; + ctx->direct_io = direct; + ctx->len = len; + ctx->cfile = cifsFileInfo_get(cfile); if (!is_sync_kiocb(iocb)) ctx->iocb = iocb; @@ -3864,19 +3642,12 @@ static ssize_t __cifs_readv( if (iter_is_iovec(to)) ctx->should_dirty = true; - if (direct) { - ctx->pos = offset; - ctx->direct_io = true; - ctx->iter = *to; - ctx->len = len; - } else { - rc = setup_aio_ctx_iter(ctx, to, READ); - if (rc) { - kref_put(&ctx->refcount, cifs_aio_ctx_release); - return rc; - } - len = ctx->len; + rc = extract_iter_to_iter(to, len, &ctx->iter, &ctx->bv); + if (rc < 0) { + kref_put(&ctx->refcount, cifs_aio_ctx_release); + return rc; } + ctx->npages = rc; /* grab a lock here due to read response handlers can access ctx */ mutex_lock(&ctx->aio_mutex); diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index f5fe5720456a..6bbc314ab84c 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -974,96 +974,6 @@ cifs_aio_ctx_release(struct kref *refcount) kfree(ctx); } -#define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024) - -int -setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw) -{ - ssize_t rc; - unsigned int cur_npages; - unsigned int npages = 0; - unsigned int i; - size_t len; - size_t count = iov_iter_count(iter); - unsigned int saved_len; - size_t start; - unsigned int max_pages = iov_iter_npages(iter, INT_MAX); - struct page **pages = NULL; - struct bio_vec *bv = NULL; - - if (iov_iter_is_kvec(iter)) { - memcpy(&ctx->iter, iter, sizeof(*iter)); - ctx->len = count; - iov_iter_advance(iter, count); - return 0; - } - - if (array_size(max_pages, sizeof(*bv)) <= CIFS_AIO_KMALLOC_LIMIT) - bv = kmalloc_array(max_pages, sizeof(*bv), GFP_KERNEL); - - if (!bv) { - bv = vmalloc(array_size(max_pages, sizeof(*bv))); - if (!bv) - return -ENOMEM; - } - - if (array_size(max_pages, sizeof(*pages)) <= CIFS_AIO_KMALLOC_LIMIT) - pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL); - - if (!pages) { - pages = vmalloc(array_size(max_pages, sizeof(*pages))); - if (!pages) { - kvfree(bv); - return -ENOMEM; - } - } - - saved_len = count; - - while (count && npages < max_pages) { - rc = iov_iter_get_pages(iter, pages, count, max_pages, &start); - if (rc < 0) { - cifs_dbg(VFS, "Couldn't get user pages (rc=%zd)\n", rc); - break; - } - - if (rc > count) { - cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc, - count); - break; - } - - iov_iter_advance(iter, rc); - count -= rc; - rc += start; - cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE); - - if (npages + cur_npages > max_pages) { - cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n", - npages + cur_npages, max_pages); - break; - } - - for (i = 0; i < cur_npages; i++) { - len = rc > PAGE_SIZE ? PAGE_SIZE : rc; - bv[npages + i].bv_page = pages[i]; - bv[npages + i].bv_offset = start; - bv[npages + i].bv_len = len - start; - rc -= len; - start = 0; - } - - npages += cur_npages; - } - - kvfree(pages); - ctx->bv = bv; - ctx->len = saved_len - count; - ctx->npages = npages; - iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len); - return 0; -} - /** * cifs_alloc_hash - allocate hash and hash context together * @name: The name of the crypto hash algo