From 9ebfdf5b18493f338237ef9861a555c2f79b0c17 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Fri, 4 Mar 2016 17:19:23 -0800 Subject: mtd: nand: check status before reporting timeout 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 diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index f2c8ff3..596a9b0 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); } -- cgit v0.10.2