From patchwork Fri Apr 18 09:38:22 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 14057110 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 845E61EE7BE; Fri, 18 Apr 2025 09:45:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744969539; cv=none; b=EP/saHjIRe7wnbTVE/ngOia9c12z5m5iDuXj0zUtt5lgA3NZKc3Py7mZwb7h+sOyINoOfxdNfUPwXlSc7rx1ve1UkShFS4Y2SEfooNpbD2PrA2Cmh1XK4RKulm9VvQoqzVAHHm43BkkKRMdjQGXgpFoBVcDOYOBXvdhSuwX8u7g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744969539; c=relaxed/simple; bh=9OP0rY0s+GQSK1skRZFWmADM/fZR4WYEsAi8q5xSNJQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=g9Y0++nm/DiCIK39+akDGuVPxGC4vPj5r0HDY4p0j3rKtipk/Wxth3l5E/v4lNoKD1LWTItrkjGAZxAzPH1ajXGzqK4kmdyLv8xRozdvztrssjd3WHmNzHMCcuK19Ol1f8ox8BO5okqa/du3TeaUiJTVxS0YWf0ZJHxuWjxl1vk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.93.142]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Zf8xw14Xqz4f3lff; Fri, 18 Apr 2025 17:45:08 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 712AF1A07BB; Fri, 18 Apr 2025 17:45:33 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgBHrGA6HwJozQ1aJw--.29179S5; Fri, 18 Apr 2025 17:45:33 +0800 (CST) From: Yu Kuai To: axboe@kernel.dk, kbusch@kernel.org Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com, johnny.chenyi@huawei.com Subject: [PATCH 1/5] brd: fix oops if write concurrent with discard Date: Fri, 18 Apr 2025 17:38:22 +0800 Message-Id: <20250418093826.3149293-2-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20250418093826.3149293-1-yukuai1@huaweicloud.com> References: <20250418093826.3149293-1-yukuai1@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: gCh0CgBHrGA6HwJozQ1aJw--.29179S5 X-Coremail-Antispam: 1UD129KBjvJXoWxZFyrGFWUGw1kAF1fAr1rCrg_yoW5Ar4kpF 43ArZ3J390qa15twnrXrn0kr15Wwn2kay8Way3Ca1Fgrs7uwnFyF1rJFWIq343Kr17CrZ3 CrWDJay8Zr18uwUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBC14x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jr4l82xGYIkIc2 x26xkF7I0E14v26r1I6r4UM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY1x0262kKe7AKxVWUtVW8Zw CF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j 6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64 vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_ Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0x vEx4A2jsIEc7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjfU5a0mUUUUU X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ From: Yu Kuai User can issue write and discard concurrently, causing following BUG_ON: cpu0: brd_submit_bio brd_do_bve copy_to_brd_setup brd_insert_page xa_lock __xa_insert xa_unlock cpu1 brd_submit_bio brd_do_discard xa_lock page = __xa_erase __free_page xa_unlock copy_to_brd brd_lookup_page page = xa_load BUG_ON(!page) Fix this problem by skipping the write, and user will get zero data later if the page is not here. Also fix following checkpatch warnings: WARNING: Deprecated use of 'kmap_atomic', prefer 'kmap_local_page' instead WARNING: Deprecated use of 'kunmap_atomic', prefer 'kunmap_local' instead Fixes: 9ead7efc6f3f ("brd: implement discard support") Signed-off-by: Yu Kuai --- drivers/block/brd.c | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 292f127cae0a..a6e4f005cb76 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -133,22 +133,22 @@ static void copy_to_brd(struct brd_device *brd, const void *src, copy = min_t(size_t, n, PAGE_SIZE - offset); page = brd_lookup_page(brd, sector); - BUG_ON(!page); - - dst = kmap_atomic(page); - memcpy(dst + offset, src, copy); - kunmap_atomic(dst); + if (page) { + dst = kmap_local_page(page); + memcpy(dst + offset, src, copy); + kunmap_local(dst); + } if (copy < n) { src += copy; sector += copy >> SECTOR_SHIFT; copy = n - copy; page = brd_lookup_page(brd, sector); - BUG_ON(!page); - - dst = kmap_atomic(page); - memcpy(dst, src, copy); - kunmap_atomic(dst); + if (page) { + dst = kmap_local_page(page); + memcpy(dst, src, copy); + kunmap_local(dst); + } } } @@ -166,9 +166,9 @@ static void copy_from_brd(void *dst, struct brd_device *brd, copy = min_t(size_t, n, PAGE_SIZE - offset); page = brd_lookup_page(brd, sector); if (page) { - src = kmap_atomic(page); + src = kmap_local_page(page); memcpy(dst, src + offset, copy); - kunmap_atomic(src); + kunmap_local(src); } else memset(dst, 0, copy); @@ -178,9 +178,9 @@ static void copy_from_brd(void *dst, struct brd_device *brd, copy = n - copy; page = brd_lookup_page(brd, sector); if (page) { - src = kmap_atomic(page); + src = kmap_local_page(page); memcpy(dst, src, copy); - kunmap_atomic(src); + kunmap_local(src); } else memset(dst, 0, copy); } @@ -208,7 +208,7 @@ static int brd_do_bvec(struct brd_device *brd, struct page *page, goto out; } - mem = kmap_atomic(page); + mem = kmap_local_page(page); if (!op_is_write(opf)) { copy_from_brd(mem + off, brd, sector, len); flush_dcache_page(page); @@ -216,7 +216,7 @@ static int brd_do_bvec(struct brd_device *brd, struct page *page, flush_dcache_page(page); copy_to_brd(brd, mem + off, sector, len); } - kunmap_atomic(mem); + kunmap_local(mem); out: return err; From patchwork Fri Apr 18 09:38:23 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 14057111 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D65121E2007; Fri, 18 Apr 2025 09:45:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744969539; cv=none; b=AArPcT3PPsWOjSHEZKYbiwRe9/+b1rp2oAzU61ah1CjC3mBULrt0ubLRSXVRUpdP3FpqxWSbg1E/p2HhmOYWWIWSg/HGygMZ9HqIUfywcRFKYfZfpP+9o19QHVka/FAv1GopfuklIcgmeq0+gLp/0VCw+ud74SbSHi3uNokTS5U= ARC-Message-Signature: i=1; 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Fri, 18 Apr 2025 17:45:33 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgBHrGA6HwJozQ1aJw--.29179S6; Fri, 18 Apr 2025 17:45:33 +0800 (CST) From: Yu Kuai To: axboe@kernel.dk, kbusch@kernel.org Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com, johnny.chenyi@huawei.com Subject: [PATCH 2/5] brd: synchronize using page and free page with rcu Date: Fri, 18 Apr 2025 17:38:23 +0800 Message-Id: <20250418093826.3149293-3-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20250418093826.3149293-1-yukuai1@huaweicloud.com> References: <20250418093826.3149293-1-yukuai1@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: gCh0CgBHrGA6HwJozQ1aJw--.29179S6 X-Coremail-Antispam: 1UD129KBjvJXoW7Kr4xtF4fJw1kXF45tr4xWFg_yoW8CF18pF 4UJ34xArZ8Cr4ay3WUX3Z0vFyrX3s7Gay8Gayxu3y5Kw4fGr9Fya48ta4Sqa45GryrCrW3 Zan0y3y8A34rCwUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBC14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jryl82xGYIkIc2 x26xkF7I0E14v26r4j6ryUM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY1x0262kKe7AKxVWUtVW8Zw CF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j 6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64 vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_ Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0x vEx4A2jsIEc7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjfU8yCGUUUUU X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ From: Yu Kuai Currently, after fetching the page by xa_load() in IO path, there is no protection and page can be freed concurrently by discard: cpu0 brd_submit_bio brd_do_bvec page = brd_lookup_page cpu1 brd_submit_bio brd_do_discard page = __xa_erase() __free_page() // page UAF Fix the problem by protecting page with rcu. Fixes: 9ead7efc6f3f ("brd: implement discard support") Signed-off-by: Yu Kuai --- drivers/block/brd.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index a6e4f005cb76..740ed13faaff 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -208,6 +208,7 @@ static int brd_do_bvec(struct brd_device *brd, struct page *page, goto out; } + rcu_read_lock(); mem = kmap_local_page(page); if (!op_is_write(opf)) { copy_from_brd(mem + off, brd, sector, len); @@ -217,11 +218,19 @@ static int brd_do_bvec(struct brd_device *brd, struct page *page, copy_to_brd(brd, mem + off, sector, len); } kunmap_local(mem); + rcu_read_unlock(); out: return err; } +static void brd_free_one_page(struct rcu_head *head) +{ + struct page *page = container_of(head, struct page, rcu_head); + + __free_page(page); +} + static void brd_do_discard(struct brd_device *brd, sector_t sector, u32 size) { sector_t aligned_sector = (sector + PAGE_SECTORS) & ~PAGE_SECTORS; @@ -232,7 +241,7 @@ static void brd_do_discard(struct brd_device *brd, sector_t sector, u32 size) while (size >= PAGE_SIZE && aligned_sector < rd_size * 2) { page = __xa_erase(&brd->brd_pages, aligned_sector >> PAGE_SECTORS_SHIFT); if (page) { - __free_page(page); + call_rcu(&page->rcu_head, brd_free_one_page); brd->brd_nr_pages--; } aligned_sector += PAGE_SECTORS; From patchwork Fri Apr 18 09:38:24 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 14057113 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8464A2046B8; Fri, 18 Apr 2025 09:45:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; 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Fri, 18 Apr 2025 17:45:15 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 53B451A0359; Fri, 18 Apr 2025 17:45:34 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgBHrGA6HwJozQ1aJw--.29179S7; Fri, 18 Apr 2025 17:45:34 +0800 (CST) From: Yu Kuai To: axboe@kernel.dk, kbusch@kernel.org Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com, johnny.chenyi@huawei.com Subject: [PATCH 3/5] brd: fix aligned_sector from brd_do_discard() Date: Fri, 18 Apr 2025 17:38:24 +0800 Message-Id: <20250418093826.3149293-4-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20250418093826.3149293-1-yukuai1@huaweicloud.com> References: <20250418093826.3149293-1-yukuai1@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: gCh0CgBHrGA6HwJozQ1aJw--.29179S7 X-Coremail-Antispam: 1UD129KBjvdXoWrtr4fGr4fZFy3GFy7Xry3CFg_yoW3uwc_Cr 15ZFs7Xr95Gr1jyr1Yy34fZr9Fv3WjqrZ5uF1Sqr9aqay8X3Z2v34qvr98Zr1UWrW5Aa4a yw1qqr47Xr42gjkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUb6xFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUWwA2048vs2IY02 0Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM2 8EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2AI xVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20x vE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xv r2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxkF7I0En4kS14v26r1q6r43Mx AIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_ Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwI xGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWx JwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcV C2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUHWlkUUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ From: Yu Kuai The calculation is just wrong, fix it by round_up(). Fixes: 9ead7efc6f3f ("brd: implement discard support") Signed-off-by: Yu Kuai --- drivers/block/brd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 740ed13faaff..21e841e09a89 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -233,7 +233,7 @@ static void brd_free_one_page(struct rcu_head *head) static void brd_do_discard(struct brd_device *brd, sector_t sector, u32 size) { - sector_t aligned_sector = (sector + PAGE_SECTORS) & ~PAGE_SECTORS; + sector_t aligned_sector = round_up(sector, PAGE_SECTORS); struct page *page; size -= (aligned_sector - sector) * SECTOR_SIZE; From patchwork Fri Apr 18 09:38:25 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 14057112 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 596EA204F6F; Fri, 18 Apr 2025 09:45:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744969540; cv=none; b=QPH3JD9lECSsQhABqVkiB5TWoaSNH5d/U1w2htC84s+JSRMQYSSrIODPAAYYtJohYdqBB0LXEB3mhPQyAz7RVLt8O2uLfEUMrBFt+vtAF3xfxRViBL08PcE1Q9OY7T7j+SMReA2QSehDy0uRE33XvySl3r4KF4C+Rj3mYZ6zw50= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744969540; c=relaxed/simple; bh=4zPHwMiowHy/kThRUPCqNfHIPBFyzhAe1GkacMCd7FA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=XogboFBS5R4lmltOywfDwAVxv9NriyvQ3bm2LWhUl1T7HR24qUeLeaZUBBG9ZXfudb7TYuyJ0R72WSOwO50znu5qylB2zdKEk65wgaadj2qfEd80gpegS4jQwczEJlQVNO95by4Yxr+EzVGHpdJ8UIAQLmmSy7khDOrwiS5Q/v8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4Zf8xy6ySsz4f3jHh; Fri, 18 Apr 2025 17:45:10 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id BA1561A1B91; Fri, 18 Apr 2025 17:45:34 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgBHrGA6HwJozQ1aJw--.29179S8; Fri, 18 Apr 2025 17:45:34 +0800 (CST) From: Yu Kuai To: axboe@kernel.dk, kbusch@kernel.org Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com, johnny.chenyi@huawei.com Subject: [PATCH 4/5] brd: fix discard end sector Date: Fri, 18 Apr 2025 17:38:25 +0800 Message-Id: <20250418093826.3149293-5-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20250418093826.3149293-1-yukuai1@huaweicloud.com> References: <20250418093826.3149293-1-yukuai1@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: gCh0CgBHrGA6HwJozQ1aJw--.29179S8 X-Coremail-Antispam: 1UD129KBjvJXoW7Cw1rCrWxuFW7Kr4UGw15Arb_yoW8Xw1rpF 4UJFZ29ry5Cr1UK3WYq3s8uryFqayxGa4fKay7u3yYkw4fGF9Fka97t34rXay8GrWfury3 A3Z3t34rZrykA3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPj14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F 4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq 3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7 IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4U M4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY1x0262kKe7AKxVWUtV W8ZwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v2 6r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2 Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_ Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMI IF0xvEx4A2jsIEc7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjfUOyIUUUUU U X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ From: Yu Kuai brd_do_discard() just aligned start sector to page, this can only work if the discard size if at least one page. For example: blkdiscard /dev/ram0 -o 5120 -l 1024 In this case, size = (1024 - (8192 - 5120)), which is a huge value. Fix the problem by round_down() the end sector. Fixes: 9ead7efc6f3f ("brd: implement discard support") Signed-off-by: Yu Kuai --- drivers/block/brd.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 21e841e09a89..bf1e1b2a0d28 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -234,18 +234,21 @@ static void brd_free_one_page(struct rcu_head *head) static void brd_do_discard(struct brd_device *brd, sector_t sector, u32 size) { sector_t aligned_sector = round_up(sector, PAGE_SECTORS); + sector_t aligned_end = round_down(sector + (size >> SECTOR_SHIFT), + PAGE_SECTORS); struct page *page; - size -= (aligned_sector - sector) * SECTOR_SIZE; + if (aligned_end <= aligned_sector) + return; + xa_lock(&brd->brd_pages); - while (size >= PAGE_SIZE && aligned_sector < rd_size * 2) { + while (aligned_sector < aligned_end && aligned_sector < rd_size * 2) { page = __xa_erase(&brd->brd_pages, aligned_sector >> PAGE_SECTORS_SHIFT); if (page) { call_rcu(&page->rcu_head, brd_free_one_page); brd->brd_nr_pages--; } aligned_sector += PAGE_SECTORS; - size -= PAGE_SIZE; } xa_unlock(&brd->brd_pages); } From patchwork Fri Apr 18 09:38:26 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 14057114 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9DBC320897F; Fri, 18 Apr 2025 09:45:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744969540; cv=none; b=fwls1fP1OB845A7PGHYo2OiZgfLvYKZl5hPT8Dk1gAQgWzQuSqT1KIYov5ZKIlouUaVl29TYYik5Kl3i5nTxTqG2Nm5FnyT18lJlAqnXjOhGLymF46TURcYGcdYBya+aBeNimwdPNhtVslK+8rpjuUrpEOi/ndcP7yTIfUzPI4U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; 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Fri, 18 Apr 2025 17:45:35 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgBHrGA6HwJozQ1aJw--.29179S9; Fri, 18 Apr 2025 17:45:34 +0800 (CST) From: Yu Kuai To: axboe@kernel.dk, kbusch@kernel.org Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com, johnny.chenyi@huawei.com Subject: [PATCH 5/5] brd: zero data for discard that is not aligned to page Date: Fri, 18 Apr 2025 17:38:26 +0800 Message-Id: <20250418093826.3149293-6-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20250418093826.3149293-1-yukuai1@huaweicloud.com> References: <20250418093826.3149293-1-yukuai1@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: gCh0CgBHrGA6HwJozQ1aJw--.29179S9 X-Coremail-Antispam: 1UD129KBjvJXoW7urW5GF43uFWrAF1rAF43Jrb_yoW8Cw4DpF 4DJryIkrW5Kr17Kw13Jwn8ZFyFv34xGayrGay7u3909w1rGF9Fyas5t3WSqFy8GrWfWF13 Aan7tryF9r1kA3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUP014x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F 4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq 3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7 IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4U M4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY1x0262kKe7AKxVWUtV W8ZwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v2 6r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2 Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUCVW8JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_ Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJw CI42IY6I8E87Iv6xkF7I0E14v26r4UJVWxJrUvcSsGvfC2KfnxnUUI43ZEXa7VUbPC7UUU UUU== X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ From: Yu Kuai Currently brd_do_discard() will just skip unaligned sectors, and in this case user will still get old data after discard. Fix this by writing zero data to unaligned sectors. Fixes: 9ead7efc6f3f ("brd: implement discard support") Signed-off-by: Yu Kuai --- drivers/block/brd.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index bf1e1b2a0d28..b5908703fb4b 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -224,6 +224,21 @@ static int brd_do_bvec(struct brd_device *brd, struct page *page, return err; } +static void brd_zero_range(struct brd_device *brd, sector_t sector, u32 size) +{ + unsigned int offset = (sector & (PAGE_SECTORS-1)) << SECTOR_SHIFT; + struct page *page; + void *dst; + + page = brd_lookup_page(brd, sector); + if (!page) + return; + + dst = kmap_local_page(page); + memset(dst + offset, 0, size); + kunmap_local(dst); +} + static void brd_free_one_page(struct rcu_head *head) { struct page *page = container_of(head, struct page, rcu_head); @@ -234,10 +249,17 @@ static void brd_free_one_page(struct rcu_head *head) static void brd_do_discard(struct brd_device *brd, sector_t sector, u32 size) { sector_t aligned_sector = round_up(sector, PAGE_SECTORS); - sector_t aligned_end = round_down(sector + (size >> SECTOR_SHIFT), - PAGE_SECTORS); + sector_t sector_end = sector + (size >> SECTOR_SHIFT); + sector_t aligned_end = round_down(sector_end, PAGE_SECTORS); struct page *page; + if (aligned_sector > sector) + brd_zero_range(brd, sector, + (aligned_sector - sector) << SECTOR_SHIFT); + if (aligned_end < sector_end) + brd_zero_range(brd, aligned_end, + (sector_end - aligned_end) << SECTOR_SHIFT); + if (aligned_end <= aligned_sector) return;