From patchwork Tue Nov 20 14:53:41 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Saenz Julienne X-Patchwork-Id: 10690727 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 E4EC25A4 for ; Tue, 20 Nov 2018 16:22:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D17912A980 for ; Tue, 20 Nov 2018 16:22:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C2BD92A993; Tue, 20 Nov 2018 16:22:53 +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=-3.6 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 339A12A980 for ; 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Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by casper.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gP7Q6-0005qm-C2; Tue, 20 Nov 2018 14:54:32 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id AB634AD94; Tue, 20 Nov 2018 14:54:08 +0000 (UTC) From: Nicolas Saenz Julienne To: stefan.wahren@i2se.com, eric@anholt.net, dave.stevenson@raspberrypi.org Subject: [PATCH 06/16] staging: vchiq_arm: rework vchiq_ioc_copy_element_data Date: Tue, 20 Nov 2018 15:53:41 +0100 Message-Id: <20181120145351.30390-7-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181120145351.30390-1-nsaenzjulienne@suse.de> References: <20181120145351.30390-1-nsaenzjulienne@suse.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181120_145430_443815_D683FF2C X-CRM114-Status: GOOD ( 17.76 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devel@driverdev.osuosl.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, Nicolas Saenz Julienne , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP The function is passed to vchiq_core.c for it to go trough all the transfer elements (an array of pointers to data) and copy them into the actual transfer memory (contiguous memory). The logic in the function was "copy an element and return, except when the element is empty, in which case look for the next non-empty element and copy it. The function will be called as many times as necessary until all the elements are copied". Now, this approach already forces the function to loop around elements and felt convoluted, so it was changed to a more straightforward "Copy all the elements into memory as long as they fit". The resulting function is shorter and simpler. Signed-off-by: Nicolas Saenz Julienne --- .../interface/vchiq_arm/vchiq_arm.c | 89 +++++++------------ 1 file changed, 31 insertions(+), 58 deletions(-) diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c index 525458551a22..7fa734991db9 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -752,74 +752,48 @@ static void close_delivered(USER_SERVICE_T *user_service) } struct vchiq_io_copy_callback_context { - struct vchiq_element *current_element; - size_t current_element_offset; + struct vchiq_element *element; + size_t element_offset; unsigned long elements_to_go; - size_t current_offset; }; -static ssize_t -vchiq_ioc_copy_element_data( - void *context, - void *dest, - size_t offset, - size_t maxsize) +static ssize_t vchiq_ioc_copy_element_data(void *context, void *dest, + size_t offset, size_t maxsize) { - long res; + struct vchiq_io_copy_callback_context *cc = context; + size_t total_bytes_copied = 0; size_t bytes_this_round; - struct vchiq_io_copy_callback_context *copy_context = - (struct vchiq_io_copy_callback_context *)context; - - if (offset != copy_context->current_offset) - return 0; - - if (!copy_context->elements_to_go) - return 0; - - /* - * Complex logic here to handle the case of 0 size elements - * in the middle of the array of elements. - * - * Need to skip over these 0 size elements. - */ - while (1) { - bytes_this_round = min(copy_context->current_element->size - - copy_context->current_element_offset, - maxsize); - - if (bytes_this_round) - break; - copy_context->elements_to_go--; - copy_context->current_element++; - copy_context->current_element_offset = 0; + while (total_bytes_copied < maxsize) { + if (!cc->elements_to_go) + return total_bytes_copied; - if (!copy_context->elements_to_go) - return 0; - } + if (!cc->element->size) { + cc->elements_to_go--; + cc->element++; + cc->element_offset = 0; + continue; + } - res = copy_from_user(dest, - copy_context->current_element->data + - copy_context->current_element_offset, - bytes_this_round); + bytes_this_round = min(cc->element->size - cc->element_offset, + maxsize - total_bytes_copied); - if (res != 0) - return -EFAULT; + if (copy_from_user(dest + total_bytes_copied, + cc->element->data + cc->element_offset, + bytes_this_round)) + return -EFAULT; - copy_context->current_element_offset += bytes_this_round; - copy_context->current_offset += bytes_this_round; + cc->element_offset += bytes_this_round; + total_bytes_copied += bytes_this_round; - /* - * Check if done with current element, and if so advance to the next. - */ - if (copy_context->current_element_offset == - copy_context->current_element->size) { - copy_context->elements_to_go--; - copy_context->current_element++; - copy_context->current_element_offset = 0; + if (cc->element_offset == cc->element->size) { + cc->elements_to_go--; + cc->element++; + cc->element_offset = 0; + } } - return bytes_this_round; + return maxsize; } /************************************************************************** @@ -836,10 +810,9 @@ vchiq_ioc_queue_message(VCHIQ_SERVICE_HANDLE_T handle, unsigned long i; size_t total_size = 0; - context.current_element = elements; - context.current_element_offset = 0; + context.element = elements; + context.element_offset = 0; context.elements_to_go = count; - context.current_offset = 0; for (i = 0; i < count; i++) { if (!elements[i].data && elements[i].size != 0)