From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.free-electrons.com (mail.free-electrons.com [62.4.15.54]) by lists.ozlabs.org (Postfix) with ESMTP id 3yQTMS024xzDqMY for ; Mon, 30 Oct 2017 20:14:43 +1100 (AEDT) Date: Mon, 30 Oct 2017 10:14:12 +0100 From: Boris Brezillon To: Cyril Bur Cc: linux-mtd@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, stewart@linux.vnet.ibm.com, dwmw2@infradead.org, computersforpeace@gmail.com, sjitindarsingh@gmail.com Subject: Re: [PATCH v4 10/10] mtd: powernv_flash: Use opal_async_wait_response_interruptible() Message-ID: <20171030101412.300b8c5d@bbrezillon> In-Reply-To: <20171010033302.20854-11-cyrilbur@gmail.com> References: <20171010033302.20854-1-cyrilbur@gmail.com> <20171010033302.20854-11-cyrilbur@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 10 Oct 2017 14:33:02 +1100 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() > 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. > > Signed-off-by: Cyril Bur Have some minor comments (see below). Once addressed you can add Acked-by: Boris Brezillon > --- > drivers/mtd/devices/powernv_flash.c | 57 +++++++++++++++++++++++-------------- > 1 file changed, 35 insertions(+), 22 deletions(-) > > diff --git a/drivers/mtd/devices/powernv_flash.c b/drivers/mtd/devices/powernv_flash.c > index 3343d4f5c4f3..42383dbca5a6 100644 > --- a/drivers/mtd/devices/powernv_flash.c > +++ b/drivers/mtd/devices/powernv_flash.c > @@ -1,7 +1,7 @@ > /* > * OPAL PNOR flash MTD abstraction > * > - * Copyright IBM 2015 > + * Copyright IBM 2015-2017 Not a big deal, but this copyright update is not really related to the change you describe in your commit message. Maybe this should be done in a separate commit. > * > * This program is free software; you can redistribute it and/or modify > * it under the terms of the GNU General Public License as published by > @@ -89,33 +89,46 @@ static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op, > return -EIO; > } > > - if (rc == OPAL_SUCCESS) > - goto out_success; > + if (rc == OPAL_ASYNC_COMPLETION) { > + rc = opal_async_wait_response_interruptible(token, &msg); > + if (rc) { > + /* > + * If we return the mtd core will free the > + * buffer we've just passed to OPAL but OPAL > + * will continue to read or write from that > + * memory. > + * It may be tempting to ultimately return 0 > + * if we're doing a read or a write since we > + * are going to end up waiting until OPAL is > + * done. However, because the MTD core sends > + * us the userspace request in chunks, we need > + * to it know we've been interrupted. ^ 'it to' ? > + */ > + rc = -EINTR; > + if (opal_async_wait_response(token, &msg)) > + dev_err(dev, "opal_async_wait_response() failed\n"); > + goto out; > + } > + rc = opal_get_async_rc(msg); > + } > > - if (rc != OPAL_ASYNC_COMPLETION) { > + /* > + * OPAL does mutual exclusion on the flash, it will return > + * OPAL_BUSY. > + * During firmware updates by the service processor OPAL may > + * be (temporarily) prevented from accessing the flash, in > + * this case OPAL will also return OPAL_BUSY. > + * Both cases aren't errors exactly but the flash could have > + * changed, userspace should be informed. > + */ > + if (rc != OPAL_SUCCESS && rc != OPAL_BUSY) > dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n", > op, rc); > - rc = -EIO; > - goto out; > - } > > - rc = opal_async_wait_response(token, &msg); > - if (rc) { > - dev_err(dev, "opal async wait failed (rc %d)\n", rc); > - rc = -EIO; > - goto out; > - } > - > - rc = opal_get_async_rc(msg); > -out_success: > - if (rc == OPAL_SUCCESS) { > - rc = 0; > - if (retlen) > + if (rc == OPAL_SUCCESS && retlen) > *retlen = len; There's one too many tabs here. > - } else { > - rc = -EIO; > - } > > + rc = opal_error_code(rc); > out: > opal_async_release_token(token); > return rc;