Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760106AbcCEBT6 (ORCPT ); Fri, 4 Mar 2016 20:19:58 -0500 Received: from mail-pa0-f48.google.com ([209.85.220.48]:33591 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759879AbcCEBT5 (ORCPT ); Fri, 4 Mar 2016 20:19:57 -0500 From: Brian Norris To: Cc: , Brian Norris , Boris Brezillon , Richard Weinberger , Harvey Hunt , Alex Smith , Niklas Cassel , Alex Smith Subject: [PATCH] mtd: nand: check status before reporting timeout Date: Fri, 4 Mar 2016 17:19:23 -0800 Message-Id: <1457140763-67571-1-git-send-email-computersforpeace@gmail.com> X-Mailer: git-send-email 2.7.0.rc3.207.g0ac5344 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1932 Lines: 45 In commit b70af9bef49b ("mtd: nand: increase ready wait timeout and report timeouts"), we increased the likelihood of scheduling during nand_wait(). This makes us more likely to hit the time_before(...) condition, since a lot of time may pass before we get scheduled again. Now, the loop was already buggy, since we don't check if the NAND is ready after exiting the loop; we simply print out a timeout warning. Fix this by doing a final status check before printing a timeout message. This isn't actually a critical bug, since the only effect is a false warning print. But too many prints never hurt anyone, did they? :) Side note: perhaps I'm not smart enough, but I'm not sure what the best policy is for this kind of loop; do we busy loop (i.e., no cond_resched()) to keep the lowest I/O latency (it's not great if the resched is delaying Richard's system ~400ms)? Or do we allow rescheduling, to play nice with the rest of the system (since some operations can take quite a while)? Reported-by: Richard Weinberger Signed-off-by: Brian Norris Reviewed-by: Boris Brezillon Reviewed-by: Richard Weinberger Reviewed-by: Harvey Hunt --- drivers/mtd/nand/nand_base.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index f2c8ff398d6c..596a9b0503da 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -566,8 +566,8 @@ void nand_wait_ready(struct mtd_info *mtd) cond_resched(); } while (time_before(jiffies, timeo)); - pr_warn_ratelimited( - "timeout while waiting for chip to become ready\n"); + if (!chip->dev_ready(mtd)) + pr_warn_ratelimited("timeout while waiting for chip to become ready\n"); out: led_trigger_event(nand_led_trigger, LED_OFF); } -- 2.7.0.rc3.207.g0ac5344