On Wed, Jun 25, 2014 at 09:20:11AM +0000, David Laight wrote: >From: Wei Yang >> On Wed, Jun 25, 2014 at 02:12:34PM +1000, Alexey Kardashevskiy wrote: >> >On 06/25/2014 11:12 AM, Wei Yang wrote: >> >> On Tue, Jun 24, 2014 at 08:06:32PM +1000, Alexey Kardashevskiy wrote: >> >>> On 06/10/2014 11:56 AM, Wei Yang wrote: >> >>>> Current iommu_table of a PE is a static field. This will have a problem when >> >>>> iommu_free_table is called. >> >>> >> >>> What kind of problem? This table is per PE and PE is not going anywhere. >> >>> >> >> >> >> Yes, for Bus PE, they will always sit in the system. When VF PE introduced, >> >> they could be released on the fly. When they are released, so do the iommu >> >> table for the PE. >> > >> >iommu_table is a part of PE struct. When PE is released, iommu_table will >> >go with it as well. Why to make is a pointer? I would understand it if you >> >added reference counting there but no - iommu_table's lifetime is equal to >> >PE lifetime. >> > >> >> Yes, iommu_talbe's life time equals to PE lifetime, so when releasing a PE we >> need to release the iommu table. Currently, there is one function to release >> the iommu table, iommu_free_table() which takes a pointer of the iommu_table >> and release it. >> >> If the iommu table in PE is just a part of PE, it will have some problem to >> release it with iommu_free_table(). That's why I make it a pointer in PE >> structure. > >What are the sizes of the iommu table and the PE structure? I calculated it in my mind, the size of iommu_table, defined in arch/powerpc/include/asm/iommu.h is 256 bytes. >If the table is a round number of pages then you probably don't want to >embed it inside the PE structure. If my understanding is correct, the iommu table structure size is not that big. > > David > -- Richard Yang Help you, Help me -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
