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[87.17.106.94]) by smtp.gmail.com with ESMTPSA id r9-20020a1709061ba900b007317f017e64sm5125916ejg.134.2022.08.21.11.04.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 Aug 2022 11:04:07 -0700 (PDT) From: "Fabio M. De Francesco" To: "Matthew Wilcox (Oracle)" , Ira Weiny , Jeff Layton , Damien Le Moal , Andrew Morton , Christian Brauner , Arnd Bergmann , Jens Axboe , "Martin K. Petersen" , Chaitanya Kulkarni , Kees Cook , Muchun Song , Roman Gushchin , "Theodore Ts'o" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "Fabio M. De Francesco" , Viacheslav Dubeyko Subject: [RESEND PATCH 1/3] hfs: Unmap the page in the "fail_page" label Date: Sun, 21 Aug 2022 20:03:58 +0200 Message-Id: <20220821180400.8198-2-fmdefrancesco@gmail.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220821180400.8198-1-fmdefrancesco@gmail.com> References: <20220821180400.8198-1-fmdefrancesco@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Several paths within hfs_btree_open() jump to the "fail_page" label where put_page() is called while the page is still mapped. Call kunmap() to unmap the page soon before put_page(). Reviewed-by: Ira Weiny Reviewed-by: Viacheslav Dubeyko Signed-off-by: Fabio M. De Francesco --- fs/hfs/btree.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c index 19017d296173..56c6782436e9 100644 --- a/fs/hfs/btree.c +++ b/fs/hfs/btree.c @@ -124,6 +124,7 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp ke return tree; fail_page: + kunmap(page); put_page(page); free_inode: tree->inode->i_mapping->a_ops = &hfs_aops; From patchwork Sun Aug 21 18:03:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Fabio M. De Francesco" X-Patchwork-Id: 12950028 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 366A6C00140 for ; Sun, 21 Aug 2022 18:04:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231348AbiHUSER (ORCPT ); Sun, 21 Aug 2022 14:04:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231317AbiHUSEO (ORCPT ); Sun, 21 Aug 2022 14:04:14 -0400 Received: from mail-ej1-x629.google.com (mail-ej1-x629.google.com [IPv6:2a00:1450:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 707CD1D0E6; Sun, 21 Aug 2022 11:04:13 -0700 (PDT) Received: by mail-ej1-x629.google.com with SMTP id ca13so6082758ejb.9; Sun, 21 Aug 2022 11:04:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc; bh=xvYbbgr6M/luqTV703HLx2cmWfU4tDlaXdSaXZbUyHM=; b=NUegbYQwz3FF2aGh1cFNGBkpLo2y3gwRRMzeE1sVCpowYI6s+4kXQFeI3xFhgysf5B AoNg7joEpp3YrZE+ptzmsZsw5RAdOjmC2hQHzDZyRVlBu7OEI+EmLL8hb7VwqOuc/Msr 5Tfhk3Tzzv8DVV81fzDgNFLp/MfCEXADbEqjHqUUtCCxQQy2Rf6lP3u1g/91N+PqOKIy Sfbdnx0y8LpGJlHa1C4j9JtElaiqthEemAcFBxYwvoz9VEp4E5xScHmRtohs7Tm+vjqh df8f76DkiCOqvyYbg6L8qCPAXWxV2/HQlwBjd0IiSnN1yd+NJkZM9TOFYD57m//e3BHN 6YVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc; bh=xvYbbgr6M/luqTV703HLx2cmWfU4tDlaXdSaXZbUyHM=; b=H0RiZfl1fk3FHy+p40kY193fOxtjBHmKsCAvUhqSy5PQ7ZnRwtbEzLu0QZ3V4EHExb azkENh5hv8K1x6U3VfuBsveMckK/OcQSNZ6RAosKdjsz91d5NeKFRkB1NWiUs4AA395W AS6oejNp2GsYRG+e4zeqXp2mxmW5kTNPdFUN3xLx/CLompidE3FSdyYYoC0VyAwSXseS iCgh1D3NTt1Nl6DS5f0mJI3GtQUzq5kAadQRXwLjB1F6bbYvYatZBcXmpAz4vg1Y5fg7 aFJ3k3IrGXFmq8A3Mw9Cxq+gWQ6ouVYj/4RcbsCFvJs94uK9MZi6wb+o0X7tid9JdQtq RlXg== X-Gm-Message-State: ACgBeo1Pe80LU2h8huD6NHoOe/6gC5AMAp4GAPW2HrGawae6Ws+cL0kz 7wqtP4jqo8/0rRcC1DH58VE= X-Google-Smtp-Source: AA6agR7vxJJpgxqTGpKAOFSGxqLF6P8Ma3cXL8yHW+VhYE/crTz0WFt1ftrG4JcMJoq9+uXjEHgXVQ== X-Received: by 2002:a17:906:6a03:b0:730:a20e:cf33 with SMTP id qw3-20020a1709066a0300b00730a20ecf33mr11154941ejc.620.1661105051992; Sun, 21 Aug 2022 11:04:11 -0700 (PDT) Received: from localhost.localdomain (host-87-17-106-94.retail.telecomitalia.it. [87.17.106.94]) by smtp.gmail.com with ESMTPSA id r9-20020a1709061ba900b007317f017e64sm5125916ejg.134.2022.08.21.11.04.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 Aug 2022 11:04:10 -0700 (PDT) From: "Fabio M. De Francesco" To: "Matthew Wilcox (Oracle)" , Ira Weiny , Jeff Layton , Damien Le Moal , Andrew Morton , Christian Brauner , Arnd Bergmann , Jens Axboe , "Martin K. Petersen" , Chaitanya Kulkarni , Kees Cook , Muchun Song , Roman Gushchin , "Theodore Ts'o" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "Fabio M. De Francesco" , Viacheslav Dubeyko Subject: [RESEND PATCH 2/3] hfs: Replace kmap() with kmap_local_page() in bnode.c Date: Sun, 21 Aug 2022 20:03:59 +0200 Message-Id: <20220821180400.8198-3-fmdefrancesco@gmail.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220821180400.8198-1-fmdefrancesco@gmail.com> References: <20220821180400.8198-1-fmdefrancesco@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org kmap() is being deprecated in favor of kmap_local_page(). Two main problems with kmap(): (1) It comes with an overhead as mapping space is restricted and protected by a global lock for synchronization and (2) it also requires global TLB invalidation when the kmap’s pool wraps and it might block when the mapping space is fully utilized until a slot becomes available. With kmap_local_page() the mappings are per thread, CPU local, can take page faults, and can be called from any context (including interrupts). It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore, the tasks can be preempted and, when they are scheduled to run again, the kernel virtual addresses are restored and still valid. Since its use in bnode.c is safe everywhere, it should be preferred. Therefore, replace kmap() with kmap_local_page() in bnode.c. Where possible, use the suited standard helpers (memzero_page(), memcpy_page()) instead of open coding kmap_local_page() plus memset() or memcpy(). Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with HIGHMEM64GB enabled. Suggested-by: Ira Weiny Reviewed-by: Viacheslav Dubeyko Signed-off-by: Fabio M. De Francesco --- fs/hfs/bnode.c | 32 ++++++++++++-------------------- 1 file changed, 12 insertions(+), 20 deletions(-) diff --git a/fs/hfs/bnode.c b/fs/hfs/bnode.c index c83fd0e8404d..2015e42e752a 100644 --- a/fs/hfs/bnode.c +++ b/fs/hfs/bnode.c @@ -21,7 +21,6 @@ void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len) int pagenum; int bytes_read; int bytes_to_read; - void *vaddr; off += node->page_offset; pagenum = off >> PAGE_SHIFT; @@ -33,9 +32,7 @@ void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len) page = node->page[pagenum]; bytes_to_read = min_t(int, len - bytes_read, PAGE_SIZE - off); - vaddr = kmap_atomic(page); - memcpy(buf + bytes_read, vaddr + off, bytes_to_read); - kunmap_atomic(vaddr); + memcpy_from_page(buf + bytes_read, page, off, bytes_to_read); pagenum++; off = 0; /* page offset only applies to the first page */ @@ -80,8 +77,7 @@ void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len) off += node->page_offset; page = node->page[0]; - memcpy(kmap(page) + off, buf, len); - kunmap(page); + memcpy_to_page(page, off, buf, len); set_page_dirty(page); } @@ -105,8 +101,7 @@ void hfs_bnode_clear(struct hfs_bnode *node, int off, int len) off += node->page_offset; page = node->page[0]; - memset(kmap(page) + off, 0, len); - kunmap(page); + memzero_page(page, off, len); set_page_dirty(page); } @@ -123,9 +118,7 @@ void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst, src_page = src_node->page[0]; dst_page = dst_node->page[0]; - memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len); - kunmap(src_page); - kunmap(dst_page); + memcpy_page(dst_page, dst, src_page, src, len); set_page_dirty(dst_page); } @@ -140,9 +133,9 @@ void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len) src += node->page_offset; dst += node->page_offset; page = node->page[0]; - ptr = kmap(page); + ptr = kmap_local_page(page); memmove(ptr + dst, ptr + src, len); - kunmap(page); + kunmap_local(ptr); set_page_dirty(page); } @@ -346,13 +339,14 @@ struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num) if (!test_bit(HFS_BNODE_NEW, &node->flags)) return node; - desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset); + desc = (struct hfs_bnode_desc *)(kmap_local_page(node->page[0]) + + node->page_offset); node->prev = be32_to_cpu(desc->prev); node->next = be32_to_cpu(desc->next); node->num_recs = be16_to_cpu(desc->num_recs); node->type = desc->type; node->height = desc->height; - kunmap(node->page[0]); + kunmap_local(desc); switch (node->type) { case HFS_NODE_HEADER: @@ -436,14 +430,12 @@ struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num) } pagep = node->page; - memset(kmap(*pagep) + node->page_offset, 0, - min((int)PAGE_SIZE, (int)tree->node_size)); + memzero_page(*pagep, node->page_offset, + min((int)PAGE_SIZE, (int)tree->node_size)); set_page_dirty(*pagep); - kunmap(*pagep); for (i = 1; i < tree->pages_per_bnode; i++) { - memset(kmap(*++pagep), 0, PAGE_SIZE); + memzero_page(*++pagep, 0, PAGE_SIZE); set_page_dirty(*pagep); - kunmap(*pagep); } clear_bit(HFS_BNODE_NEW, &node->flags); wake_up(&node->lock_wq); From patchwork Sun Aug 21 18:04:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Fabio M. 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[87.17.106.94]) by smtp.gmail.com with ESMTPSA id r9-20020a1709061ba900b007317f017e64sm5125916ejg.134.2022.08.21.11.04.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 Aug 2022 11:04:13 -0700 (PDT) From: "Fabio M. De Francesco" To: "Matthew Wilcox (Oracle)" , Ira Weiny , Jeff Layton , Damien Le Moal , Andrew Morton , Christian Brauner , Arnd Bergmann , Jens Axboe , "Martin K. Petersen" , Chaitanya Kulkarni , Kees Cook , Muchun Song , Roman Gushchin , "Theodore Ts'o" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "Fabio M. De Francesco" , Viacheslav Dubeyko Subject: [RESEND PATCH 3/3] hfs: Replace kmap() with kmap_local_page() in btree.c Date: Sun, 21 Aug 2022 20:04:00 +0200 Message-Id: <20220821180400.8198-4-fmdefrancesco@gmail.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220821180400.8198-1-fmdefrancesco@gmail.com> References: <20220821180400.8198-1-fmdefrancesco@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org kmap() is being deprecated in favor of kmap_local_page(). Two main problems with kmap(): (1) It comes with an overhead as mapping space is restricted and protected by a global lock for synchronization and (2) it also requires global TLB invalidation when the kmap’s pool wraps and it might block when the mapping space is fully utilized until a slot becomes available. With kmap_local_page() the mappings are per thread, CPU local, can take page faults, and can be called from any context (including interrupts). It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore, the tasks can be preempted and, when they are scheduled to run again, the kernel virtual addresses are restored and still valid. Since its use in btree.c is safe everywhere, it should be preferred. Therefore, replace kmap() with kmap_local_page() in btree.c. Where possible, use the suited standard helpers (memzero_page(), memcpy_page()) instead of open coding kmap_local_page() plus memset() or memcpy(). Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with HIGHMEM64GB enabled. Suggested-by: Ira Weiny Reviewed-by: Viacheslav Dubeyko Signed-off-by: Fabio M. De Francesco --- fs/hfs/btree.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c index 56c6782436e9..2fa4b1f8cc7f 100644 --- a/fs/hfs/btree.c +++ b/fs/hfs/btree.c @@ -80,7 +80,8 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp ke goto free_inode; /* Load the header */ - head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); + head = (struct hfs_btree_header_rec *)(kmap_local_page(page) + + sizeof(struct hfs_bnode_desc)); tree->root = be32_to_cpu(head->root); tree->leaf_count = be32_to_cpu(head->leaf_count); tree->leaf_head = be32_to_cpu(head->leaf_head); @@ -119,12 +120,12 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp ke tree->node_size_shift = ffs(size) - 1; tree->pages_per_bnode = (tree->node_size + PAGE_SIZE - 1) >> PAGE_SHIFT; - kunmap(page); + kunmap_local(head); put_page(page); return tree; fail_page: - kunmap(page); + kunmap_local(head); put_page(page); free_inode: tree->inode->i_mapping->a_ops = &hfs_aops; @@ -170,7 +171,8 @@ void hfs_btree_write(struct hfs_btree *tree) return; /* Load the header */ page = node->page[0]; - head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); + head = (struct hfs_btree_header_rec *)(kmap_local_page(page) + + sizeof(struct hfs_bnode_desc)); head->root = cpu_to_be32(tree->root); head->leaf_count = cpu_to_be32(tree->leaf_count); @@ -181,7 +183,7 @@ void hfs_btree_write(struct hfs_btree *tree) head->attributes = cpu_to_be32(tree->attributes); head->depth = cpu_to_be16(tree->depth); - kunmap(page); + kunmap_local(head); set_page_dirty(page); hfs_bnode_put(node); } @@ -269,7 +271,7 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) off += node->page_offset; pagep = node->page + (off >> PAGE_SHIFT); - data = kmap(*pagep); + data = kmap_local_page(*pagep); off &= ~PAGE_MASK; idx = 0; @@ -282,7 +284,7 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) idx += i; data[off] |= m; set_page_dirty(*pagep); - kunmap(*pagep); + kunmap_local(data); tree->free_nodes--; mark_inode_dirty(tree->inode); hfs_bnode_put(node); @@ -291,14 +293,14 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) } } if (++off >= PAGE_SIZE) { - kunmap(*pagep); - data = kmap(*++pagep); + kunmap_local(data); + data = kmap_local_page(*++pagep); off = 0; } idx += 8; len--; } - kunmap(*pagep); + kunmap_local(data); nidx = node->next; if (!nidx) { printk(KERN_DEBUG "create new bmap node...\n"); @@ -314,7 +316,7 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) off = off16; off += node->page_offset; pagep = node->page + (off >> PAGE_SHIFT); - data = kmap(*pagep); + data = kmap_local_page(*pagep); off &= ~PAGE_MASK; } } @@ -361,20 +363,20 @@ void hfs_bmap_free(struct hfs_bnode *node) } off += node->page_offset + nidx / 8; page = node->page[off >> PAGE_SHIFT]; - data = kmap(page); + data = kmap_local_page(page); off &= ~PAGE_MASK; m = 1 << (~nidx & 7); byte = data[off]; if (!(byte & m)) { pr_crit("trying to free free bnode %u(%d)\n", node->this, node->type); - kunmap(page); + kunmap_local(data); hfs_bnode_put(node); return; } data[off] = byte & ~m; set_page_dirty(page); - kunmap(page); + kunmap_local(data); hfs_bnode_put(node); tree->free_nodes++; mark_inode_dirty(tree->inode);