Messages in this thread Patch in this message | | | Date | Fri, 25 Jun 2004 19:39:19 +0200 | From | Takashi Iwai <> | Subject | Re: [discuss] Re: 32-bit dma allocations on 64-bit platforms |
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At Fri, 25 Jun 2004 19:30:46 +0200, Andrea Arcangeli wrote: > > On Fri, Jun 25, 2004 at 05:50:04PM +0200, Takashi Iwai wrote: > > --- linux-2.6.7/arch/i386/kernel/pci-dma.c-dist 2004-06-24 15:56:46.017473544 +0200 > > +++ linux-2.6.7/arch/i386/kernel/pci-dma.c 2004-06-25 17:43:42.509366917 +0200 > > @@ -23,11 +23,22 @@ void *dma_alloc_coherent(struct device * > > if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff)) > > gfp |= GFP_DMA; > > > > + again: > > ret = (void *)__get_free_pages(gfp, get_order(size)); > > > > - if (ret != NULL) { > > + if (ret == NULL) { > > + if (dev && (gfp & GFP_DMA)) { > > + gfp &= ~GFP_DMA; > > I would find cleaner to use __GFP_DMA in the whole file, this is not > about your changes, previous code used GFP_DMA too. The issue is that if > we change GFP_DMA to add a __GFP_HIGH or similar, the above will clear > the other bitflags too.
Indeed.
> > > + (((unsigned long)*dma_handle + size - 1) & ~(unsigned long)dev->coherent_dma_mask)) { > > + free_pages((unsigned long)ret, get_order(size)); > > + return NULL; > > + } > > I would do the memset and setting of dma_handle after the above check.
Yep. The below is the corrected version.
Thanks!
Takashi
--- linux-2.6.7/arch/i386/kernel/pci-dma.c-dist 2004-06-24 15:56:46.017473544 +0200 +++ linux-2.6.7/arch/i386/kernel/pci-dma.c 2004-06-25 19:38:26.334210809 +0200 @@ -21,13 +21,24 @@ void *dma_alloc_coherent(struct device * gfp &= ~(__GFP_DMA | __GFP_HIGHMEM); if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff)) - gfp |= GFP_DMA; + gfp |= __GFP_DMA; + again: ret = (void *)__get_free_pages(gfp, get_order(size)); - if (ret != NULL) { - memset(ret, 0, size); + if (ret == NULL) { + if (dev && (gfp & __GFP_DMA)) { + gfp &= ~__GFP_DMA; + goto again; + } + } else { *dma_handle = virt_to_phys(ret); + if (!(gfp & __GFP_DMA) && + (((unsigned long)*dma_handle + size - 1) & ~(unsigned long)dev->coherent_dma_mask)) { + free_pages((unsigned long)ret, get_order(size)); + return NULL; + } + memset(ret, 0, size); } return ret; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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