Re: [PATCH] cciss: return 0 from driver probe function on success,not 1
From: Jens Axboe
Date: Fri Nov 01 2013 - 12:21:04 EST
On 11/01/2013 10:06 AM, Stephen M. Cameron wrote:
> From: Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx>
>
> A return value of 1 is interpreted as an error. See pci_driver.
> in local_pci_probe(). If you're wondering how this ever could
> have worked, it's because it used to be the case that only return
> values less than zero were interpreted as failure. But even in
> the current kernel if the driver registers its various entry
> points with the kernel, and then returns a value which is
> interpreted as failure, those registrations aren't undone, so
> the driver still mostly works. However, the driver's remove
> function wouldn't be called on rmmod, and pci power management
> functions wouldn't work. In the case of Smart Array, since it
> has a battery backed cache (or else no cache) even if the driver
> is not shut down properly as long as there is no outstanding
> i/o, nothing too bad happens, which is why it took so long to
> notice.
>
> Requesting backport to stable because the change to pci-driver.c
> which requires driver probe functions to return 0 occurred between
> 2.6.35 and 2.6.36 (the pci power management breakage) and again
> between 3.7 and 3.8 (pci_dev->driver getting set to NULL in
> local_pci_probe() preventing driver remove function from being
> called on rmmod.)
The original patch went in two days ago, so it's a little difficult for
me to update it unfortunately. But you can include lots of this in the
pci-driver.c warning print patch instead.
--
Jens Axboe
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