On Wed, Aug 01, 2012 at 08:45:19AM +0200, Marek Vasut wrote:

Dear Guenter Roeck,

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On Wed, Aug 01, 2012 at 08:10:37AM +0200, Marek Vasut wrote:

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Dear Shawn Guo,

quoted

On Tue, Jul 31, 2012 at 10:42:28PM -0700, Guenter Roeck wrote:

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On Wed, Aug 01, 2012 at 01:58:56PM +0800, Shawn Guo wrote:

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On Tue, Jul 31, 2012 at 10:29:47PM -0700, Guenter Roeck wrote:

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Anyone up for writing some patches ? If not, I'll do it.

Go ahead.

Ok, will do. It isn't that simple, actually, since at least some of
the drivers also call spi_master_get(), and thus need two calls to
spi_master_put() (or a call to spi_master_put and a call to kfree).

Hmm, are you saying that there must be a spi_master_put call matching
spi_alloc_master?  I think we only need to have spi_master_get and
spi_master_put matched.

Naw, spi_master_get() does refcounting, spi_alloc_master() doesnt. You
don't need to match spi_alloc_master() with spi_master_put()

I must be missing something.  Why do almost all spi drivers call it in the
error path, even if there is no call to spi_master_get ?

To push the refcounting to 0, to deallocate the device, I'd say ...

Guess we are in violent agreement. The sequence would then either be
	master = spi_alloc_device();
	...
	spi_master_put(master);
or
	master = spi_alloc_device();
	...
	kfree(master);

which makes sense to me. Question still is why most drivers neither call kfree()
nor spi_master_put() in the remove function.

Thanks,
Guenter