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author | Brian Norris <computersforpeace@gmail.com> | 2016-03-05 01:19:23 (GMT) |
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committer | Brian Norris <computersforpeace@gmail.com> | 2016-03-07 21:51:11 (GMT) |
commit | 9ebfdf5b18493f338237ef9861a555c2f79b0c17 (patch) | |
tree | 0e1c2041a5cad1919cca33f3153de9e932bec986 /drivers/mtd | |
parent | 3707b2c3d21f7c9f8c6aadba79ef012f0bbad10c (diff) | |
download | linux-9ebfdf5b18493f338237ef9861a555c2f79b0c17.tar.xz |
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 <richard@nod.at>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Harvey Hunt <harvey.hunt@imgtec.com>
Diffstat (limited to 'drivers/mtd')
-rw-r--r-- | drivers/mtd/nand/nand_base.c | 4 |
1 files changed, 2 insertions, 2 deletions
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); } |