On Thu, 2017-06-29 at 16:54 +1000, Cyril Bur wrote:
> The OPAL calls performed in this driver shouldn't be using
> opal_async_wait_response() as this performs a wait_event() which, on
> long running OPAL calls could result in hung task warnings. wait_event()
> also prevents timely signal delivery which is also undesirable.
>
> This patch also attempts to quieten down the use of dev_err() when
> errors haven't actually occurred and also to return better information up
> the stack rather than always -EIO.
So what happens when you get a signal then ? The async op is still in
progress, will the callers properly handle that ?
For example, for a read, OPAL will potentially still be writing to
the destination buffer. Are the callers expecting this ?
That sounds very broken to me ....
You should simply limit the amount of flash that can be affected by
a single call to avoid long hung tasks.
> Signed-off-by: Cyril Bur <cyril...@gmail.com>
> ---
> drivers/mtd/devices/powernv_flash.c | 18 +++++++++++-------
> 1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mtd/devices/powernv_flash.c
> b/drivers/mtd/devices/powernv_flash.c
> index 7b41af06f4fe..a7c5ae2b2898 100644
> --- a/drivers/mtd/devices/powernv_flash.c
> +++ b/drivers/mtd/devices/powernv_flash.c
> @@ -88,19 +88,23 @@ static int powernv_flash_async_op(struct mtd_info *mtd,
> enum flash_op op,
> }
>
> if (rc != OPAL_ASYNC_COMPLETION) {
> - dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",
> - op, rc);
> + if (rc != OPAL_BUSY)
> + dev_err(dev, "opal_flash_async_op(op=%d) failed (rc
> %d)\n",
> + op, rc);
> opal_async_release_token(token);
> - rc = -EIO;
> + rc = opal_error_code(rc);
> goto out;
> }
>
> - rc = opal_async_wait_response(token, &msg);
> + rc = opal_async_wait_response_interruptible(token, &msg);
> opal_async_release_token(token);
> mutex_unlock(&info->lock);
> if (rc) {
> - dev_err(dev, "opal async wait failed (rc %d)\n", rc);
> - return -EIO;
> + if (rc == -ERESTARTSYS)
> + rc = -EINTR;
> + else
> + dev_err(dev, "opal async wait failed (rc %d)\n", rc);
> + return rc;
> }
>
> rc = opal_get_async_rc(msg);
> @@ -109,7 +113,7 @@ static int powernv_flash_async_op(struct mtd_info *mtd,
> enum flash_op op,
> if (retlen)
> *retlen = len;
> } else {
> - rc = -EIO;
> + rc = opal_error_code(rc);
> }
>
> return rc;
