Re: [patch] x86: add compilation checks to pci_unmap_ macros

From: Matti Linnanvuori
Date: Mon Jun 30 2008 - 02:35:02 EST


2008/6/29 Jan Engelhardt <jengelh@xxxxxxxxxx>:
>
> On Sunday 2008-06-29 08:22, Matti Linnanvuori wrote:
>>+#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME) dma_addr_t ADDR_NAME[0];
>>+#define DECLARE_PCI_UNMAP_LEN(LEN_NAME) unsigned LEN_NAME[0];
>>+#define pci_unmap_addr(PTR, ADDR_NAME) sizeof((PTR)->ADDR_NAME)
>>+#define pci_unmap_addr_set(PTR, ADDR_NAME, VAL) \
>>+ do { break; } while (pci_unmap_addr(PTR, ADDR_NAME))
>
> Mh. If addr_name happens to be non-0 for some reason (like, a typo),
> then this just introduces a lockup.
> (Better to have a no-op with a typo than a sudden lockup.

No, it does not lock up because there is a break statement in the do block.

> Given
> that these are no-ops means they are deprecated, is not it the case?)

I don't think they are deprecated. There is no text about the
deprecation in kernel documents.
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