From patchwork Tue Jun 27 09:54:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Petr Tesarik X-Patchwork-Id: 13294250 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7BEDEB64DC for ; Tue, 27 Jun 2023 09:57:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231827AbjF0J5q (ORCPT ); Tue, 27 Jun 2023 05:57:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231685AbjF0J5N (ORCPT ); Tue, 27 Jun 2023 05:57:13 -0400 Received: from frasgout12.his.huawei.com (unknown [14.137.139.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1398D30E5; Tue, 27 Jun 2023 02:56:13 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.227]) by frasgout12.his.huawei.com (SkyGuard) with ESMTP id 4Qr0CM3Cphz9v7cZ; Tue, 27 Jun 2023 17:43:43 +0800 (CST) Received: from A2101119013HW2.china.huawei.com (unknown [10.45.153.185]) by APP1 (Coremail) with SMTP id LxC2BwBnwdzesZpknnvHAw--.39096S4; Tue, 27 Jun 2023 10:55:33 +0100 (CET) From: Petr Tesarik To: Stefano Stabellini , Thomas Bogendoerfer , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), "H. Peter Anvin" , Greg Kroah-Hartman , "Rafael J. Wysocki" , Juergen Gross , Oleksandr Tyshchenko , Christoph Hellwig , Marek Szyprowski , Robin Murphy , Andy Shevchenko , Hans de Goede , Jason Gunthorpe , Kees Cook , Saravana Kannan , xen-devel@lists.xenproject.org (moderated list:XEN HYPERVISOR ARM), linux-arm-kernel@lists.infradead.org (moderated list:ARM PORT), linux-kernel@vger.kernel.org (open list), linux-mips@vger.kernel.org (open list:MIPS), iommu@lists.linux.dev (open list:XEN SWIOTLB SUBSYSTEM) Cc: Roberto Sassu , Kefeng Wang , petr@tesarici.cz Subject: [PATCH v3 2/7] swiotlb: add documentation and rename swiotlb_do_find_slots() Date: Tue, 27 Jun 2023 11:54:24 +0200 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-CM-TRANSID: LxC2BwBnwdzesZpknnvHAw--.39096S4 X-Coremail-Antispam: 1UD129KBjvJXoW3GrWfGF48Gr13WrW3tFWUArb_yoW7XF43pF 4rKFs0qFZ8Jr1xC3sFkw48uF1Ska1kK347uayS9ryF9rnxJr9agFyqyrW5Xa4rJrs7uF4U Ja4avrW8GF45Xr7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUma14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jryl82xGYIkIc2 x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UM2 8EF7xvwVC2z280aVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv6xkF7I0E14v26r4UJVWxJr1l e2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI 8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwAC jcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7CjxVA2Y2ka0x kIwI1lc7CjxVAKzI0EY4vE52x082I5MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY 6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17 CEb7AF67AKxVWrXVW8Jr1lIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI 42IY6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCw CI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I0E14v26r4UJVWxJrUvcSsG vfC2KfnxnUUI43ZEXa7VUURwZ5UUUUU== X-CM-SenderInfo: hshw23xhvd2x3n6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Petr Tesarik Add some kernel-doc comments and move the existing documentation of struct io_tlb_slot to its correct location. The latter was forgotten in commit 942a8186eb445 ("swiotlb: move struct io_tlb_slot to swiotlb.c"). Use the opportunity to give swiotlb_do_find_slots() a more descriptive name, which makes it clear how it differs from swiotlb_find_slots(). Signed-off-by: Petr Tesarik --- include/linux/swiotlb.h | 15 ++++++++---- kernel/dma/swiotlb.c | 52 ++++++++++++++++++++++++++++++++++++----- 2 files changed, 57 insertions(+), 10 deletions(-) diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index b38045be532d..9f486843a66a 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -77,10 +77,6 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys, * @end. For default swiotlb, this is command line adjustable via * setup_io_tlb_npages. * @used: The number of used IO TLB block. - * @list: The free list describing the number of free entries available - * from each index. - * @orig_addr: The original address corresponding to a mapped entry. - * @alloc_size: Size of the allocated buffer. * @debugfs: The dentry to debugfs. * @late_alloc: %true if allocated using the page allocator * @force_bounce: %true if swiotlb bouncing is forced @@ -113,6 +109,17 @@ struct io_tlb_mem { #endif }; +/** + * is_swiotlb_buffer() - check if a physical address belongs to a swiotlb + * @dev: Device which has mapped the buffer. + * @paddr: Physical address within the DMA buffer. + * + * Check if @paddr points into a bounce buffer. + * + * Return: + * * %true if @paddr points into a bounce buffer + * * %false otherwise + */ static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr) { struct io_tlb_mem *mem = dev->dma_io_tlb_mem; diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 63d318059f27..888c25a9bfcc 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -62,6 +62,13 @@ #define INVALID_PHYS_ADDR (~(phys_addr_t)0) +/** + * struct io_tlb_slot - IO TLB slot descriptor + * @orig_addr: The original address corresponding to a mapped entry. + * @alloc_size: Size of the allocated buffer. + * @list: The free list describing the number of free entries available + * from each index. + */ struct io_tlb_slot { phys_addr_t orig_addr; size_t alloc_size; @@ -632,11 +639,22 @@ static void dec_used(struct io_tlb_mem *mem, unsigned int nslots) } #endif /* CONFIG_DEBUG_FS */ -/* - * Find a suitable number of IO TLB entries size that will fit this request and - * allocate a buffer from that IO TLB pool. +/** + * area_find_slots() - search for slots in one IO TLB memory area + * @dev: Device which maps the buffer. + * @area_index: Index of the IO TLB memory area to be searched. + * @orig_addr: Original (non-bounced) IO buffer address. + * @alloc_size: Total requested size of the bounce buffer, + * including initial alignment padding. + * @alloc_align_mask: Required alignment of the allocated buffer. + * + * Find a suitable sequence of IO TLB entries for the request and allocate + * a buffer from the given IO TLB memory area. + * This function takes care of locking. + * + * Return: Index of the first allocated slot, or -1 on error. */ -static int swiotlb_do_find_slots(struct device *dev, int area_index, +static int area_find_slots(struct device *dev, int area_index, phys_addr_t orig_addr, size_t alloc_size, unsigned int alloc_align_mask) { @@ -731,6 +749,19 @@ static int swiotlb_do_find_slots(struct device *dev, int area_index, return slot_index; } +/** + * swiotlb_find_slots() - search for slots in the whole swiotlb + * @dev: Device which maps the buffer. + * @orig_addr: Original (non-bounced) IO buffer address. + * @alloc_size: Total requested size of the bounce buffer, + * including initial alignment padding. + * @alloc_align_mask: Required alignment of the allocated buffer. + * + * Search through the whole software IO TLB to find a sequence of slots that + * match the allocation constraints. + * + * Return: Index of the first allocated slot, or -1 on error. + */ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, size_t alloc_size, unsigned int alloc_align_mask) { @@ -739,8 +770,8 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, int i = start, index; do { - index = swiotlb_do_find_slots(dev, i, orig_addr, alloc_size, - alloc_align_mask); + index = area_find_slots(dev, i, orig_addr, alloc_size, + alloc_align_mask); if (index >= 0) return index; if (++i >= mem->nareas) @@ -750,6 +781,15 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, return -1; } +/** + * mem_used() - get number of used slots in an allocator + * @mem: Software IO TLB allocator. + * + * The result is not accurate, because there is no locking of individual + * areas. + * + * Return: Approximate number of used slots. + */ static unsigned long mem_used(struct io_tlb_mem *mem) { int i;