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由 Suresh Siddha 提交于
pci mmap code was doing memtype reserve for a while now. Recently we added memtype tracking in remap_pfn_range, and pci code indirectly calls remap_pfn_range. So, we don't need seperate tracking in pci code anymore. Which means a patch that removes ~50 lines of code :-). Also, recently we found out that the pci tracking is not working as we expect it to work in some cases. Specifically, userlevel X mmap of pci, with some recent version of X, is having a problem with vm_page_prot getting reset. The pci tracking uses vm_page_prot to pass on the protection type from parent to child during fork. a) Parent does a pci mmap b) We look at PAT and get either UC_MINUS or WC mapping for parent c) Store that mapping type in vma vm_page_prot for future use d) This thread does a fork e) Fork results in mmap_ops ->open for the child process f) We get the vm_page_prot from vma and reserve that type for the child process But, between c) and e) above, the vma vm_page_prot is getting reset to zero. This results in PAT reserve failing at the time of fork as in here. http://marc.info/?l=linux-kernel&m=123858163103240&w=2 This cleanup makes the above problem go away as we do not depend on vm_page_prot in our PAT code anymore. Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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