From patchwork Tue Aug 1 06:23:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Petr Tesarik X-Patchwork-Id: 13335810 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D66D6C0015E for ; Tue, 1 Aug 2023 06:26:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=wZHH/CFb0Ojdx1nv9C5FxlKRyIP50yJR8mgRGIgg/Rk=; b=IRzpIQRjwt++TT r8kKn9YRdK3Qb8i6elOjiQcNzTpn4igPcFR9jj21ZMATrHqJiOopYFNF7IjBoc8Wt/UpD+iPivd3l 5NbkPd4n1kJX6Nlu05z40gmIkKU9/VBHQCSk2LBdwonqAMivpfetxJ0UjwhyvBamIMsRu/ImhrMOG jxI94YuRRkctPuA5cujoJn27A+GieyS+s63H07OQ22nLamNGzmkNPCSusHnni0/opz+tmsWnbcDot KEqd4VcVTI0zgblum1sU9wXJ1jlWr8omvA78O4crbaQC+HM+XER+5jeDClpo28/vpuAZUwAFsSEHK DPw9aG0/j8xggiszU1fQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qQipp-000S47-21; Tue, 01 Aug 2023 06:26:21 +0000 Received: from [14.137.139.46] (helo=frasgout13.his.huawei.com) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qQipm-000S2f-0k for linux-arm-kernel@lists.infradead.org; Tue, 01 Aug 2023 06:26:20 +0000 Received: from mail02.huawei.com (unknown [172.18.147.228]) by frasgout13.his.huawei.com (SkyGuard) with ESMTP id 4RFPwB3v1xz9xvdn for ; Tue, 1 Aug 2023 14:14:50 +0800 (CST) Received: from A2101119013HW2.china.huawei.com (unknown [10.81.220.249]) by APP1 (Coremail) with SMTP id LxC2BwCHOroapchkgAwYAA--.27948S5; Tue, 01 Aug 2023 07:25:39 +0100 (CET) From: Petr Tesarik To: Stefano Stabellini , Russell King , 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 , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Petr Tesarik , Jonathan Corbet , Andy Shevchenko , Hans de Goede , James Seo , James Clark , Kees Cook , 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), linux-mm@kvack.org (open list:SLAB ALLOCATOR) Cc: Roberto Sassu , petr@tesarici.cz Subject: [PATCH v7 3/9] swiotlb: add documentation and rename swiotlb_do_find_slots() Date: Tue, 1 Aug 2023 08:23:58 +0200 Message-Id: <7a92817b18ce0e1bd38967784f53bf76a43cb886.1690871004.git.petr.tesarik.ext@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-CM-TRANSID: LxC2BwCHOroapchkgAwYAA--.27948S5 X-Coremail-Antispam: 1UD129KBjvJXoW3GrWfGF4UuFy8tF1xZF1kKrg_yoW7ur4rpF 4rt3Z8tFs8Jr1xC39Fkw48uF1S9w4kK347uFWavryF9rnrJr9agFyktrW5XFyrJFW8uF4U Ja4a9r48Gr13Xr7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUQm14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JrWl82xGYIkIc2 x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Gr0_Xr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26r4j6F4UM28EF7xvwVC2z280aVCY1x0267AKxVW8Jr0_Cr1U M2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjx v20xvE14v26r1Y6r17McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1l F7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8cxan2 IY04v7MxkF7I0En4kS14v26r1q6r43MxkF7I0Ew4C26cxK6c8Ij28IcwCF04k20xvY0x0E wIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E74 80Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Wrv_Gr1UMIIYrxkI7VAKI48JMIIF0xvE 2Ix0cI8IcVAFwI0_Gr0_Xr1lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4UJVWxJr1lIxAIcV CF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIE c7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjfU8Z2-UUUUU X-CM-SenderInfo: hshw23xhvd2x3n6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230731_232618_551122_711DC84D X-CRM114-Status: GOOD ( 23.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 and make it clear how it differs from swiotlb_find_slots(). Signed-off-by: Petr Tesarik --- include/linux/swiotlb.h | 15 +++++++--- kernel/dma/swiotlb.c | 61 +++++++++++++++++++++++++++++++++++++---- 2 files changed, 66 insertions(+), 10 deletions(-) diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index 2d453b3e7771..31625ae507ea 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -76,10 +76,6 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys, * @nslabs: The number of IO TLB blocks (in groups of 64) between @start and * @end. For default swiotlb, this is command line adjustable via * setup_io_tlb_npages. - * @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 @@ -111,6 +107,17 @@ 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 0840bc15fb53..66793b59c290 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; @@ -635,11 +642,22 @@ 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. +/** + * swiotlb_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 swiotlb_area_find_slots(struct device *dev, int area_index, phys_addr_t orig_addr, size_t alloc_size, unsigned int alloc_align_mask) { @@ -734,6 +752,19 @@ 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) { @@ -742,8 +773,8 @@ 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 = swiotlb_area_find_slots(dev, i, orig_addr, alloc_size, + alloc_align_mask); if (index >= 0) return index; if (++i >= mem->nareas) @@ -755,6 +786,15 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, #ifdef CONFIG_DEBUG_FS +/** + * mem_used() - get number of used slots in an allocator + * @mem: Software IO TLB allocator. + * + * The result is accurate in this version of the function, because an atomic + * counter is available if CONFIG_DEBUG_FS is set. + * + * Return: Number of used slots. + */ static unsigned long mem_used(struct io_tlb_mem *mem) { return atomic_long_read(&mem->total_used); @@ -762,6 +802,15 @@ static unsigned long mem_used(struct io_tlb_mem *mem) #else /* !CONFIG_DEBUG_FS */ +/** + * 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;