Re: [PATCH 0/6] Clean up the sdio_uart driver and fix the tty code

[David Vrabel <david.vrabel@csr.com>]

Alan Cox wrote:
> 
> The claim method takes the mutex, checks if it is NULL and acts
> accordingly but it releases the mutex, which makes it useless as the code
> then uses port->func. If I move the release of the mutex to the
> release_func method then that fixes almost all cases.
> 
> The one I'm stuck on is this
> 
> 
> 		CPU1				CPU2
> 
> 
> 	sdio_uart_irq
> 					sdio_uart_port_remove
> 					port->func = NULL;
> 	sdio_in
> 	BUG_ON

This is actually happening?  sdio_claim_host()/sdio_release_host() act
like a mutex so sdio_uart_port_remove() will wait in sdio_claim_host()
until sdio_uart_irq() returns (SDIO interrupt handlers are called with
the host claimed).

David
-- 
David Vrabel, Senior Software Engineer, Drivers
CSR, Churchill House, Cambridge Business Park,  Tel: +44 (0)1223 692562
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