GFP_DMA Janitation

GFP_DMA Janitation

[Matthew Wilcox]

I know there's a lot of clean-up and janitorial work going on at the
moment, so maybe someone already fixed the bogus uses of GFP_DMA in
drivers/scsi?  For those who're not aware, GFP_DMA is _only_ a flag,
not a full specifier.  ie it should be used as
	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA); 
rather than
	buffer = kmalloc(512, GFP_DMA);
which is how sr.c uses it at present.

Current offenders:

drivers/scsi/aha1542.c:703:             SCpnt->host_scribble = (unsigned char *) kmalloc(512, GFP_DMA);
drivers/scsi/megaraid.c:5020:   _tv = (void *)__get_free_pages(GFP_DMA, order);
drivers/scsi/pluto.c:120:       fcs = (struct ctrl_inquiry *) kmalloc (sizeof (struct ctrl_inquiry) * fcscount, GFP_DMA);
drivers/scsi/sd.c:1124: buffer = kmalloc(512, GFP_DMA);
drivers/scsi/sr.c:596:  buffer = kmalloc(512, GFP_DMA);
drivers/scsi/sr.c:708:  buffer = kmalloc(512, GFP_DMA);
drivers/scsi/sr_ioctl.c:99:             bounce_buffer = (char *) kmalloc(cgc->buflen, GFP_DMA);

The other users of GFP_DMA seem to use it correctly.

BTW, not specifing anything with GFP_DMA leads to the allocation currently
being performed as GFP_ATOMIC, only without the permission to access
the emergency pools.  A terribly risky situation.

-- 
"It's not Hollywood.  War is real, war is primarily not about defeat or
victory, it is about death.  I've seen thousands and thousands of dead bodies.
Do you think I want to have an academic debate on this subject?" -- Robert Fisk

Re: GFP_DMA Janitation

[Matt Domsch]

> I know there's a lot of clean-up and janitorial work going on at the
> moment, so maybe someone already fixed the bogus uses of GFP_DMA in
> drivers/scsi?
> drivers/scsi/megaraid.c:5020:   _tv = (void *)__get_free_pages(GFP_DMA, order);

The megaraid 2.00.2 driver (2.00.1 is in -ac right now) gets this right 
(in fact, there are no GFP_DMA allocations ever, it uses the PCI DMA API 
properly).

Thanks,
Matt

-- 
Matt Domsch
Sr. Software Engineer, Lead Engineer, Architect
Dell Linux Solutions www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com