diff options
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | mm/memory.c | 31 |
2 files changed, 16 insertions, 17 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 35f811b0cd6..2f6e2f886d4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -804,6 +804,8 @@ int copy_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma); void unmap_mapping_range(struct address_space *mapping, loff_t const holebegin, loff_t const holelen, int even_cows); +int follow_phys(struct vm_area_struct *vma, unsigned long address, + unsigned int flags, unsigned long *prot, resource_size_t *phys); int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, void *buf, int len, int write); diff --git a/mm/memory.c b/mm/memory.c index 1e8f0d347c0..79f28e35d4f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2981,9 +2981,9 @@ int in_gate_area_no_task(unsigned long addr) #endif /* __HAVE_ARCH_GATE_AREA */ #ifdef CONFIG_HAVE_IOREMAP_PROT -static resource_size_t follow_phys(struct vm_area_struct *vma, - unsigned long address, unsigned int flags, - unsigned long *prot) +int follow_phys(struct vm_area_struct *vma, + unsigned long address, unsigned int flags, + unsigned long *prot, resource_size_t *phys) { pgd_t *pgd; pud_t *pud; @@ -2992,24 +2992,26 @@ static resource_size_t follow_phys(struct vm_area_struct *vma, spinlock_t *ptl; resource_size_t phys_addr = 0; struct mm_struct *mm = vma->vm_mm; + int ret = -EINVAL; - VM_BUG_ON(!(vma->vm_flags & (VM_IO | VM_PFNMAP))); + if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) + goto out; pgd = pgd_offset(mm, address); if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) - goto no_page_table; + goto out; pud = pud_offset(pgd, address); if (pud_none(*pud) || unlikely(pud_bad(*pud))) - goto no_page_table; + goto out; pmd = pmd_offset(pud, address); if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) - goto no_page_table; + goto out; /* We cannot handle huge page PFN maps. Luckily they don't exist. */ if (pmd_huge(*pmd)) - goto no_page_table; + goto out; ptep = pte_offset_map_lock(mm, pmd, address, &ptl); if (!ptep) @@ -3024,13 +3026,13 @@ static resource_size_t follow_phys(struct vm_area_struct *vma, phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */ *prot = pgprot_val(pte_pgprot(pte)); + *phys = phys_addr; + ret = 0; unlock: pte_unmap_unlock(ptep, ptl); out: - return phys_addr; -no_page_table: - return 0; + return ret; } int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, @@ -3041,12 +3043,7 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, void *maddr; int offset = addr & (PAGE_SIZE-1); - if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) - return -EINVAL; - - phys_addr = follow_phys(vma, addr, write, &prot); - - if (!phys_addr) + if (follow_phys(vma, addr, write, &prot, &phys_addr)) return -EINVAL; maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot); |