From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CAB5314265E; Thu, 13 Jun 2024 11:38:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718278686; cv=none; b=ngksmJS5HamRjknvY7HAige3xI9sLWquLxdKjfqdyK2faAxWy2xIYhPLNHe5vktNm2OWsQy4vaAOePn57jc6n6+rdghcnqVXgP01WJoUaMYyZw+lZMi3Ludgi+dvC4zUkky0t5pctu74NOux8e7BoJjs5ECGDiMWjDMtm0MDUYw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718278686; c=relaxed/simple; bh=hS5fqyBMlQIeWnEHdHPmI3A01rXlCJsXdmF1Fowrqho=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uxvaBSdcUGNJrJci3zDJeFPTQ6TkDGByfJmLLO/wrTk1fDCHk/EMvx7ekGbM10EMA7oGqn00YeM8bJ1B4OYb1tEamKohuPvt46otmit1X3vlaH6Rohaw3x2bWzzhB4FO6trtCnvo3NMjdshzK1uzx+S0aXDZMePXCcozLhiwivI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tYkocDvy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="tYkocDvy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54C7FC2BBFC; Thu, 13 Jun 2024 11:38:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718278686; bh=hS5fqyBMlQIeWnEHdHPmI3A01rXlCJsXdmF1Fowrqho=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tYkocDvy2+NeA18RpoKfMHwQnume96wUC3mm6FeJIM6Jy3TnUACoqbGnoMgOG6Vbu gprRgmK5ZDb2DzcwlVb++0zM+UDAotvTwSewFsYDI/GXBPvfhOmFSMAROeqAA+eW8L XuNfevmSILohQVV2BBcXhLoio9iqqVsgd+ha4bwQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Manivannan Sadhasivam , Bart Van Assche , Can Guo , Andrew Halaney , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 4.19 035/213] scsi: ufs: core: Perform read back after disabling interrupts Date: Thu, 13 Jun 2024 13:31:23 +0200 Message-ID: <20240613113229.353444758@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240613113227.969123070@linuxfoundation.org> References: <20240613113227.969123070@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andrew Halaney [ Upstream commit e4a628877119bd40164a651d20321247b6f94a8b ] Currently, interrupts are cleared and disabled prior to registering the interrupt. An mb() is used to complete the clear/disable writes before the interrupt is registered. mb() ensures that the write completes, but completion doesn't mean that it isn't stored in a buffer somewhere. The recommendation for ensuring these bits have taken effect on the device is to perform a read back to force it to make it all the way to the device. This is documented in device-io.rst and a talk by Will Deacon on this can be seen over here: https://youtu.be/i6DayghhA8Q?si=MiyxB5cKJXSaoc01&t=1678 Let's do that to ensure these bits hit the device. Because the mb()'s purpose wasn't to add extra ordering (on top of the ordering guaranteed by writel()/readl()), it can safely be removed. Fixes: 199ef13cac7d ("scsi: ufs: avoid spurious UFS host controller interrupts") Reviewed-by: Manivannan Sadhasivam Reviewed-by: Bart Van Assche Reviewed-by: Can Guo Signed-off-by: Andrew Halaney Link: https://lore.kernel.org/r/20240329-ufs-reset-ensure-effect-before-delay-v5-8-181252004586@redhat.com Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/ufs/ufshcd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 6e420aab18452..b6129b822ed18 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -8105,7 +8105,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq) * Make sure that UFS interrupts are disabled and any pending interrupt * status is cleared before registering UFS interrupt handler. */ - mb(); + ufshcd_readl(hba, REG_INTERRUPT_ENABLE); /* IRQ registration */ err = devm_request_irq(dev, irq, ufshcd_intr, IRQF_SHARED, UFSHCD, hba); -- 2.43.0