From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 822B8C43603 for ; Wed, 11 Dec 2019 16:04:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56EF4214D8 for ; Wed, 11 Dec 2019 16:04:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576080292; bh=jfHW+7eSa8lBKY6GqNwLQXRRfJytTLOmmixQEGzxVZQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=LYSi47CPCWDJQZBJ/4SWk0OOK8TkdCSlWlsY9uJucmWYX2Fe9T0y5krdSpTfHvEFG n0IQdnpynEk/oMZFX0l5qqUijq0JuweyuRMWCizsNv9AcohxYi9sbNMNjruolXPK70 +BWAqQbq8ruAi/JirXoYJCEA/eVvOkIhJVaFV5pg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731295AbfLKQEq (ORCPT ); Wed, 11 Dec 2019 11:04:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:35610 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731286AbfLKPM7 (ORCPT ); Wed, 11 Dec 2019 10:12:59 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 874A22465B; Wed, 11 Dec 2019 15:12:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576077178; bh=jfHW+7eSa8lBKY6GqNwLQXRRfJytTLOmmixQEGzxVZQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KMMooxCvrs1bj1vgzvj3ANqifVco5ltIrlhX4CsoRw8i0I8MiipxzE8dQsRHrT5Ai pOxFUzXiUHm/Cttdnnq2xbzPgFmZjOwvaKE18ZLmIebL7n98agxT2aQZTe6Uuhd1KR 3DloKlwg3IzP+aeOsn/sAH2YjXgn0iPTJTvV9CPU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kars de Jong , Finn Thain , "Martin K . Petersen" , Sasha Levin , linux-scsi@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 062/134] scsi: zorro_esp: Limit DMA transfers to 65536 bytes (except on Fastlane) Date: Wed, 11 Dec 2019 10:10:38 -0500 Message-Id: <20191211151150.19073-62-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191211151150.19073-1-sashal@kernel.org> References: <20191211151150.19073-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Kars de Jong [ Upstream commit 02f7e9f351a9de95577eafdc3bd413ed1c3b589f ] When using this driver on a Blizzard 1260, there were failures whenever DMA transfers from the SCSI bus to memory of 65535 bytes were followed by a DMA transfer of 1 byte. This caused the byte at offset 65535 to be overwritten with 0xff. The Blizzard hardware can't handle single byte DMA transfers. Besides this issue, limiting the DMA length to something that is not a multiple of the page size is very inefficient on most file systems. It seems this limit was chosen because the DMA transfer counter of the ESP by default is 16 bits wide, thus limiting the length to 65535 bytes. However, the value 0 means 65536 bytes, which is handled by the ESP and the Blizzard just fine. It is also the default maximum used by esp_scsi when drivers don't provide their own dma_length_limit() function. The limit of 65536 bytes can be used by all boards except the Fastlane. The old driver used a limit of 65532 bytes (0xfffc), which is reintroduced in this patch. Fixes: b7ded0e8b0d1 ("scsi: zorro_esp: Limit DMA transfers to 65535 bytes") Link: https://lore.kernel.org/r/20191112175523.23145-1-jongk@linux-m68k.org Signed-off-by: Kars de Jong Reviewed-by: Finn Thain Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/zorro_esp.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/zorro_esp.c b/drivers/scsi/zorro_esp.c index ca8e3abeb2c7a..a23a8e5794f5c 100644 --- a/drivers/scsi/zorro_esp.c +++ b/drivers/scsi/zorro_esp.c @@ -218,7 +218,14 @@ static int fastlane_esp_irq_pending(struct esp *esp) static u32 zorro_esp_dma_length_limit(struct esp *esp, u32 dma_addr, u32 dma_len) { - return dma_len > 0xFFFF ? 0xFFFF : dma_len; + return dma_len > (1U << 16) ? (1U << 16) : dma_len; +} + +static u32 fastlane_esp_dma_length_limit(struct esp *esp, u32 dma_addr, + u32 dma_len) +{ + /* The old driver used 0xfffc as limit, so do that here too */ + return dma_len > 0xfffc ? 0xfffc : dma_len; } static void zorro_esp_reset_dma(struct esp *esp) @@ -604,7 +611,7 @@ static const struct esp_driver_ops fastlane_esp_ops = { .esp_write8 = zorro_esp_write8, .esp_read8 = zorro_esp_read8, .irq_pending = fastlane_esp_irq_pending, - .dma_length_limit = zorro_esp_dma_length_limit, + .dma_length_limit = fastlane_esp_dma_length_limit, .reset_dma = zorro_esp_reset_dma, .dma_drain = zorro_esp_dma_drain, .dma_invalidate = fastlane_esp_dma_invalidate, -- 2.20.1