Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH] net: via-rhine: fix compiler warning | Date | Wed, 30 Apr 2014 09:35:28 +0000 |
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From: Alexey Charkov [mailto:alchark@gmail.com]
> 2014-04-30 12:49 GMT+04:00 David Laight <David.Laight@aculab.com>: > > From: Jan Moskyto Matejka > >> Fixed different size cast warning: > >> > >> drivers/net/ethernet/via/via-rhine.c: In function rhine_init_one_platform: > >> drivers/net/ethernet/via/via-rhine.c:1132:13: warning: cast from pointer to integer of different > >> size [-Wpointer-to-int-cast] > >> revision = (u32)match->data; > >> ^ > >> > >> That code was added in commit 2d283862dc62daead9db0dc89cd0d0351e91f765 > >> ("net: via-rhine: add OF bus binding"). > > ... > >> diff --git a/drivers/net/ethernet/via/via-rhine.c b/drivers/net/ethernet/via/via-rhine.c > >> index 4fa9201..76d18e0 100644 > >> --- a/drivers/net/ethernet/via/via-rhine.c > >> +++ b/drivers/net/ethernet/via/via-rhine.c > >> @@ -288,7 +288,7 @@ MODULE_DEVICE_TABLE(pci, rhine_pci_tbl); > >> * (for quirks etc.) > >> */ > >> static struct of_device_id rhine_of_tbl[] = { > >> - { .compatible = "via,vt8500-rhine", .data = (void *)0x84 }, > >> + { .compatible = "via,vt8500-rhine", .data = (u32 []) { 0x84 } }, > >> { } /* terminate list */ > >> }; > >> MODULE_DEVICE_TABLE(of, rhine_of_tbl); > >> @@ -1129,7 +1129,7 @@ static int rhine_init_one_platform(struct platform_device *pdev) > >> if (!irq) > >> return -EINVAL; > >> > >> - revision = (u32)match->data; > >> + revision = *((u32 *) match->data); > >> if (!revision) > >> return -EINVAL; > > > > Both those casts look horrid. > > I'm not entirely convinced that the first is valid C - It would have to be > > something specific to C99 initialisers. > > Casts like *(u32 *)foo are also likely to be bugs (esp. on BE systems) > > so themselves start ringing alarm bells. > > > > So why not just: > > revision = (unsigned long)match->data; > > and add a comment that the 0x84 is the revision - #define ?? > > There is no particular reason why it should be u32 now - this is a > leftover from the previous iteration of code where revision was a > separate property in DT (sized u32). It actually mirrors the > respective field in struct pci_dev, which is u8 - don't see any issue > defining it as unsigned long (and also changing the definition in > struct rhine_private).
I'd guess that the field in 'struct rhine_private' only needs to be large enough for the domain of the values that are actually saved in it. If these are versions (of something) then a fixed size type (or just int) is probably more appropriate.
David
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