Messages in this thread | | | Date | Tue, 26 Oct 2010 17:03:06 +0200 | From | Michał Nazarewicz <> | Subject | Re: [PATCH 1/7] USB: gadget: file_storage: put_device() in error recovery |
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On Tue, 26 Oct 2010 16:09:27 +0200, Alan Stern <stern@rowland.harvard.edu> wrote:
> On Tue, 26 Oct 2010, Michal Nazarewicz wrote: >> This commit fixes some issues with File-backed Storage Gadget >> error recovery when registering LUN's devices. >> >> First of all, when device_register() fails the device still >> needs to be put. However, because lun_release() decreases >> fsg->ref reference counter the counter must be incremented >> beforehand. > > Correct. > >> Second of all, after any of the device_create_file()s fails, >> device_unregister() is called which in turn (indirectly) calls >> lun_release() which decrements fsg->ref. So, again, the >> reference counter must be incremented beforehand. > > Correct. > >> Lastly, if the first or the second device_create_file() >> succeeds, the files are never removed. To fix it, >> device_remove_file() needs to be called. This is done by >> simply marking LUN as registered prior to creating files so >> that fsg_unbind() can handle removing files. > > Correct.
>> Hope I'm not late for 37? > > No doubt it is too late to get into the merge window.
Ah, yes, that what I meant. I was hoping to get the whole set in -rc1, since some of the patches are purely coding style fixes.
>> diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c >> index d4fdf65..e0504a1 100644 >> --- a/drivers/usb/gadget/file_storage.c >> +++ b/drivers/usb/gadget/file_storage.c >> @@ -3392,21 +3392,19 @@ static int __init fsg_bind(struct usb_gadget *gadget) >> dev_set_name(&curlun->dev,"%s-lun%d", >> dev_name(&gadget->dev), i); >> >> - if ((rc = device_register(&curlun->dev)) != 0) { >> + kref_get(&fsg->ref); >> + rc = device_register(&curlun->dev); >> + if (rc) { >> INFO(fsg, "failed to register LUN%d: %d\n", i, rc); >> - goto out; >> - } >> - if ((rc = device_create_file(&curlun->dev, >> - &dev_attr_ro)) != 0 || >> - (rc = device_create_file(&curlun->dev, >> - &dev_attr_nofua)) != 0 || >> - (rc = device_create_file(&curlun->dev, >> - &dev_attr_file)) != 0) { >> - device_unregister(&curlun->dev); >> + put_device(&curlun->dev); >> goto out; >> } >> curlun->registered = 1; >> - kref_get(&fsg->ref); >> + >> + if ((rc = device_create_file(&curlun->dev, &dev_attr_ro)) || >> + (rc = device_create_file(&curlun->dev, &dev_attr_nofua)) || >> + (rc = device_create_file(&curlun->dev, &dev_attr_file))) >> + goto out; > > As long as you're changing these anyway, you may as well use the style > most developers seem to prefer: > > rc = device_create_file(&curlun->dev, &dev_attr_ro); > if (rc) > goto out; > ...
But then it'd be total of 9 lines consisting of three 3-line ifs. I decided that it would be more readable with a single if even though it is not compliant with coding style. What do you think? I can just resend it.
> After all, you did the same thing in the device_register() call above. > Apart from this small matter, ACK.
Thanks.
-- Best regards, _ _ | Humble Liege of Serenely Enlightened Majesty of o' \,=./ `o | Computer Science, Michał "mina86" Nazarewicz (o o) +----[mina86*mina86.com]---[mina86*jabber.org]----ooO--(_)--Ooo-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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