From 5a3ae276057840f0e60664c12fc3ef80aa59d1d4 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Fri, 3 Apr 2009 14:21:52 -0700 Subject: [PATCH] x86, PAT: Remove duplicate memtype reserve in pci mmap 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: Suresh Siddha Signed-off-by: Venkatesh Pallipadi Signed-off-by: Linus Torvalds --- arch/x86/pci/i386.c | 46 --------------------------------------------- 1 file changed, 46 deletions(-) diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c index f234a37bd428..f1817f71e009 100644 --- a/arch/x86/pci/i386.c +++ b/arch/x86/pci/i386.c @@ -258,24 +258,7 @@ void pcibios_set_master(struct pci_dev *dev) pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat); } -static void pci_unmap_page_range(struct vm_area_struct *vma) -{ - u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT; - free_memtype(addr, addr + vma->vm_end - vma->vm_start); -} - -static void pci_track_mmap_page_range(struct vm_area_struct *vma) -{ - u64 addr = (u64)vma->vm_pgoff << PAGE_SHIFT; - unsigned long flags = pgprot_val(vma->vm_page_prot) - & _PAGE_CACHE_MASK; - - reserve_memtype(addr, addr + vma->vm_end - vma->vm_start, flags, NULL); -} - static struct vm_operations_struct pci_mmap_ops = { - .open = pci_track_mmap_page_range, - .close = pci_unmap_page_range, .access = generic_access_phys, }; @@ -283,11 +266,6 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine) { unsigned long prot; - u64 addr = vma->vm_pgoff << PAGE_SHIFT; - unsigned long len = vma->vm_end - vma->vm_start; - unsigned long flags; - unsigned long new_flags; - int retval; /* I/O space cannot be accessed via normal processor loads and * stores on this platform. @@ -308,30 +286,6 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, vma->vm_page_prot = __pgprot(prot); - flags = pgprot_val(vma->vm_page_prot) & _PAGE_CACHE_MASK; - retval = reserve_memtype(addr, addr + len, flags, &new_flags); - if (retval) - return retval; - - if (flags != new_flags) { - if (!is_new_memtype_allowed(flags, new_flags)) { - free_memtype(addr, addr+len); - return -EINVAL; - } - flags = new_flags; - vma->vm_page_prot = __pgprot( - (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK) | - flags); - } - - if (((vma->vm_pgoff < max_low_pfn_mapped) || - (vma->vm_pgoff >= (1UL<<(32 - PAGE_SHIFT)) && - vma->vm_pgoff < max_pfn_mapped)) && - ioremap_change_attr((unsigned long)__va(addr), len, flags)) { - free_memtype(addr, addr + len); - return -EINVAL; - } - if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, vma->vm_end - vma->vm_start, vma->vm_page_prot)) -- 2.20.1