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 904E3199386; Thu, 6 Jun 2024 14:13:33 +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=1717683213; cv=none; b=O1xfUi8rXs7zUXvFRC+Jktu1oVUhCfAcWOZBlZVXLYZ8n4vY5qETqOmT4CqpzIkAV1SASbKopipWgKH1eQ3JcQ0OyONahqWmJL01NetZ7ZP1d2HfGgihpsHco8CIFFLHuzncq95fIhHvJjZEeFJ+5V6z5ymqKWqpOaPd6SKjm88= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717683213; c=relaxed/simple; bh=lUetS9aPcw0Lo/PcYI7E2cnu5l9TpvvUSxOPFk7+jcU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=D6A6mSQJnd3d4UWhU5JUA104Xky0GTdYWllQDnxVXYn1sHtmZ7gXZ8PN7XHLeQNVVBxDHXatQLrvyJF9gBdFLOemGv9179jeGF6wBVON5Prbcdg/+99u94v5ulw42XH0ATBV5wndOofQOFXksZIX191WWZcIc95SRDsTdVTS0F4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1+Rc+VSO; 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="1+Rc+VSO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E5D5C2BD10; Thu, 6 Jun 2024 14:13:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1717683213; bh=lUetS9aPcw0Lo/PcYI7E2cnu5l9TpvvUSxOPFk7+jcU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1+Rc+VSOVJelgsanUvj443OE5c159hR+HDtL4260xYQ9PhSe7OC1F7n6rGs2YXUmX cIgZJVWXBdnUBS1jt/m/DNgVIQoIAB5aPqwzslnz/KzLrzV1kyzx8jw9xdW9MPW3D1 FVCOZNSudmJSM+FIREu0I5NoNzC+AvqmpWiiold4= 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 6.6 156/744] scsi: ufs: core: Perform read back after disabling interrupts Date: Thu, 6 Jun 2024 15:57:08 +0200 Message-ID: <20240606131737.424026055@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240606131732.440653204@linuxfoundation.org> References: <20240606131732.440653204@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-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/ufs/core/ufshcd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index cd1b9db8543dc..2371b00c56be9 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -10369,7 +10369,7 @@ 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