Messages in this thread | | | Subject | Re: [PATCH] 2.6.6 invalid usage of GFP_DMA in drivers/scsi/pluto.c | From | Yury Umanets <> | Date | Tue, 08 Jun 2004 14:07:28 +0300 |
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On Tue, 2004-06-08 at 13:17, Andrew Morton wrote: > Yury Umanets <torque@ukrpost.net> wrote: > > > > Hello Andrew, guys, > > > > Found this, what seems to be an invalid usage of GFP_DMA flag. Is this > > patch okay? > > Nope. > > GFP_DMA means "from the lower 16MB of memory". It's needed for crufty old > eisa hardware which only does 24-bit DMA. This is clear. And sure, it shows that caller wants some memory from DMA zone if it is possible.
What I mean is that, GFP_DMA seems to be not full specifier and only flag which can be used along with something else.
Say gfp mask roughly consist of two kinds on instructions: * what memory zone to use - zone specifier. * how to behave during allocation (IO, sleep, etc) - behavior specifier.
My concern is will it behave correctly with only GFP_DMA? It seems to behave like do not use emergency pools and do not wait at the same time what is risky. Is that right?
> It's meaningless to OR this with > GFP_KERNEL.
> > However it's a bit odd that GFP_DMA implies !__GFP_WAIT. It would be valid > to hunt down GFP_DMA users who should really be using GFP_DMA|__GFP_WAIT,
Seems that all GFP_DMA users use it with __GFP_WAIT or GFP_KERNEL. And I'd prefer to add __GFP_WAIT here also.
> but this stuff is so old and crufty I'd be inclined to leave it all alone. > > > > > > --- ./linux-2.6.6/drivers/scsi/pluto.c Mon May 10 05:32:27 2004 > > +++ ./linux-2.6.6-modified/drivers/scsi/pluto.c Tue Jun 8 11:26:07 2004 > > @@ -117,7 +117,8 @@ int __init pluto_detect(Scsi_Host_Templa > > #endif > > return 0; > > } > > - fcs = (struct ctrl_inquiry *) kmalloc (sizeof (struct ctrl_inquiry) * > > fcscount, GFP_DMA); > > + fcs = (struct ctrl_inquiry *) kmalloc (sizeof (struct ctrl_inquiry) * > > fcscount, > > + GFP_KERNEL | GFP_DMA); > > if (!fcs) { > > printk ("PLUTO: Not enough memory to probe\n"); > > return 0; > > >
> Your patch is wordwrapped and uses weird headers (please omit the leading > ./ from the pathnames). Sorry, next will use another mailer.
-- umka
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