[PATCH 4.14 31/64] spi: fix IDR collision on systems with both fixed and dynamic SPI bus numbers

[PATCH 4.14 31/64] spi: fix IDR collision on systems with both fixed and dynamic SPI bus numbers

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kirill Kapranov <kirill.kapranov@compulab.co.il>

commit 1a4327fbf4554d5b78d75b19a13d40d6de220159 upstream.

On systems where some controllers get a dynamic ID assigned and some have
a fixed number (e.g. from ACPI tables), the current implementation might
run into an IDR collision: in case of a fixed bus number is gotten by a
driver (but not marked busy in IDR tree) and a driver with dynamic bus
number gets the same ID and predictably fails.

Fix this by means of checking-in fixed IDsin IDR as far as dynamic ones
at the moment of the controller registration.

Fixes: 9b61e302210e (spi: Pick spi bus number from Linux idr or spi alias)
Signed-off-by: Kirill Kapranov <kirill.kapranov@compulab.co.il>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/spi/spi.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2135,6 +2135,15 @@ int spi_register_controller(struct spi_c
 		if (WARN(id < 0, "couldn't get idr"))
 			return id;
 		ctlr->bus_num = id;
+	} else {
+		/* devices with a fixed bus num must check-in with the num */
+		mutex_lock(&board_lock);
+		id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
+			ctlr->bus_num + 1, GFP_KERNEL);
+		mutex_unlock(&board_lock);
+		if (WARN(id < 0, "couldn't get idr"))
+			return id == -ENOSPC ? -EBUSY : id;
+		ctlr->bus_num = id;
 	}
 	INIT_LIST_HEAD(&ctlr->queue);
 	spin_lock_init(&ctlr->queue_lock);

Re: [PATCH 4.14 31/64] spi: fix IDR collision on systems with both fixed and dynamic SPI bus numbers

[Sudip Mukherjee]

Hi Greg,

On Thu, Sep 27, 2018 at 10:03 AM, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> 4.14-stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> From: Kirill Kapranov <kirill.kapranov@compulab.co.il>
>
> commit 1a4327fbf4554d5b78d75b19a13d40d6de220159 upstream.
>
> On systems where some controllers get a dynamic ID assigned and some have
> a fixed number (e.g. from ACPI tables), the current implementation might
> run into an IDR collision: in case of a fixed bus number is gotten by a
> driver (but not marked busy in IDR tree) and a driver with dynamic bus
> number gets the same ID and predictably fails.
>
> Fix this by means of checking-in fixed IDsin IDR as far as dynamic ones
> at the moment of the controller registration.
>
> Fixes: 9b61e302210e (spi: Pick spi bus number from Linux idr or spi alias)
> Signed-off-by: Kirill Kapranov <kirill.kapranov@compulab.co.il>
> Signed-off-by: Mark Brown <broonie@kernel.org>
> Cc: stable@vger.kernel.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There is another later patch which fixes this patch.

04b2d03a7565 ("spi: Fix double IDR allocation with DT aliases") , can
you please add it to the release also..


--
Regards
Sudip

Re: [PATCH 4.14 31/64] spi: fix IDR collision on systems with both fixed and dynamic SPI bus numbers

[Kirill Kapranov]

Hi Greg,

Sudip is absolutely right, the patch he mentioned,
  04b2d03a7565 ("spi: Fix double IDR allocation with DT aliases"),
MUST be added too with the mine.

Sudip, thank you for reminding.
-- 
Best Regards,
Kirill

> Hi Greg,
> 
> On Thu, Sep 27, 2018 at 10:03 AM, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
>> 4.14-stable review patch.  If anyone has any objections, please let me know.
>>
>> ------------------
>>
>> From: Kirill Kapranov <kirill.kapranov@compulab.co.il>
>>
>> commit 1a4327fbf4554d5b78d75b19a13d40d6de220159 upstream.
>>
>> On systems where some controllers get a dynamic ID assigned and some have
>> a fixed number (e.g. from ACPI tables), the current implementation might
>> run into an IDR collision: in case of a fixed bus number is gotten by a
>> driver (but not marked busy in IDR tree) and a driver with dynamic bus
>> number gets the same ID and predictably fails.
>>
>> Fix this by means of checking-in fixed IDsin IDR as far as dynamic ones
>> at the moment of the controller registration.
>>
>> Fixes: 9b61e302210e (spi: Pick spi bus number from Linux idr or spi alias)
>> Signed-off-by: Kirill Kapranov <kirill.kapranov@compulab.co.il>
>> Signed-off-by: Mark Brown <broonie@kernel.org>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> There is another later patch which fixes this patch.
> 
> 04b2d03a7565 ("spi: Fix double IDR allocation with DT aliases") , can
> you please add it to the release also..
> 
> 
> --
> Regards
> Sudip
> 

Re: [PATCH 4.14 31/64] spi: fix IDR collision on systems with both fixed and dynamic SPI bus numbers

[Greg Kroah-Hartman]

On Thu, Sep 27, 2018 at 03:04:20PM +0300, Kirill Kapranov wrote:
> Hi Greg,
> 
> Sudip is absolutely right, the patch he mentioned,
>  04b2d03a7565 ("spi: Fix double IDR allocation with DT aliases"),
> MUST be added too with the mine.
> 
> Sudip, thank you for reminding.

Thanks, I'll go queue this up now.

greg k-h

Re: [PATCH 4.14 31/64] spi: fix IDR collision on systems with both fixed and dynamic SPI bus numbers

[Mark Brown]

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On Thu, Sep 27, 2018 at 03:04:20PM +0300, Kirill Kapranov wrote:

> Sudip is absolutely right, the patch he mentioned,
>  04b2d03a7565 ("spi: Fix double IDR allocation with DT aliases"),
> MUST be added too with the mine.

> Sudip, thank you for reminding.

Yes, they're both required.

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