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 22F96387; Thu, 13 Jun 2024 12:30:10 +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=1718281810; cv=none; b=BKeNP4HCWITz/jq5S2AoQUma2dxGkm41INox+wqhjHe74wkVSrcX2CiPc/UM7IoLty+U2/VogWEu5gDjZWfPTaZZsRjDksWqrEOvMVBsM2omczy6S5WdEcVliXl7lp6krEPYFfkIWrEX8tJ/vYRf+3PVVHSLiRnXsjAGbGMwFwA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718281810; c=relaxed/simple; bh=OHYeKGHF5DkyET55PLb7whaUjOQPPS8EGLFzc+w9wms=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Qhtg4COi8D9BmYd2hETjTAzpgAfpAxHjjXL6D305NNopNEwA48P/kg3E8E75Wg7bAPSdW+bdoWIF24/um6RbcF5O+evxVnOCD98VVkgz6FlF6aCt9nSELXNovcnZXh0vSEKB3a1r5F9I5mR2Fur2CrT2XP0yfijo281ykDaSEWw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PS/Egfep; 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="PS/Egfep" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D0BCC2BBFC; Thu, 13 Jun 2024 12:30:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718281810; bh=OHYeKGHF5DkyET55PLb7whaUjOQPPS8EGLFzc+w9wms=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PS/Egfep9SLFAbgFyqaBLgm7P2Ii1Qa5NXG/qBbXV9iXLxdEhd/n6Oc1NkmFBx/AX oUlBIRTtsaLG+7QhJjzkcGS9W9YHB2dLs4i4Xl3CbJFO+Rph1bN0fa92LTsIrvfunL MzErlczlVCJcbnybczF26VK6Q20SUmNQEf+mX560= 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 5.15 064/402] scsi: ufs: core: Perform read back after disabling interrupts Date: Thu, 13 Jun 2024 13:30:21 +0200 Message-ID: <20240613113304.634127017@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240613113302.116811394@linuxfoundation.org> References: <20240613113302.116811394@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 5.15-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 03b33c34f7024..1b8fdeb053529 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -9500,7 +9500,7 @@ 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