cregit-Linux how code gets into the kernel

Release 4.8 mm/mincore.c

Directory: mm
 *      linux/mm/mincore.c
 * Copyright (C) 1994-2006  Linus Torvalds

 * The mincore() system call.
#include <linux/pagemap.h>
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/syscalls.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/hugetlb.h>

#include <asm/uaccess.h>
#include <asm/pgtable.h>

static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr, unsigned long end, struct mm_walk *walk) { #ifdef CONFIG_HUGETLB_PAGE unsigned char present; unsigned char *vec = walk->private; /* * Hugepages under user process are always in RAM and never * swapped out, but theoretically it needs to be checked. */ present = pte && !huge_pte_none(huge_ptep_get(pte)); for (; addr != end; vec++, addr += PAGE_SIZE) *vec = present; walk->private = vec; #else BUG(); #endif return 0; }


naoya horiguchinaoya horiguchi6166.30%228.57%
johannes weinerjohannes weiner1920.65%342.86%
linus torvaldslinus torvalds1213.04%228.57%

/* * Later we can get more picky about what "in core" means precisely. * For now, simply check to see if the page is in the page cache, * and is up to date; i.e. that no page-in operation would be required * at this time if an application were to map and access this page. */
static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff) { unsigned char present = 0; struct page *page; /* * When tmpfs swaps out a page from a file, any process mapping that * file will not get a swp_entry_t in its pte, but rather it is like * any other file mapping (ie. marked !present and faulted in with * tmpfs's .fault). So swapped out tmpfs mappings are tested here. */ #ifdef CONFIG_SWAP if (shmem_mapping(mapping)) { page = find_get_entry(mapping, pgoff); /* * shmem/tmpfs may return swap: account for swapcache * page too. */ if (radix_tree_exceptional_entry(page)) { swp_entry_t swp = radix_to_swp_entry(page); page = find_get_page(swap_address_space(swp), swp.val); } } else page = find_get_page(mapping, pgoff); #else page = find_get_page(mapping, pgoff); #endif if (page) { present = PageUptodate(page); put_page(page); } return present; }


johannes weinerjohannes weiner8366.94%330.00%
hugh dickinshugh dickins2822.58%110.00%
nick pigginnick piggin75.65%220.00%
shaohua lishaohua li32.42%110.00%
linus torvaldslinus torvalds21.61%220.00%
kirill a. shutemovkirill a. shutemov10.81%110.00%

static int __mincore_unmapped_range(unsigned long addr, unsigned long end, struct vm_area_struct *vma, unsigned char *vec) { unsigned long nr = (end - addr) >> PAGE_SHIFT; int i; if (vma->vm_file) { pgoff_t pgoff; pgoff = linear_page_index(vma, addr); for (i = 0; i < nr; i++, pgoff++) vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff); } else { for (i = 0; i < nr; i++) vec[i] = 0; } return nr; }


johannes weinerjohannes weiner9581.20%250.00%
nick pigginnick piggin1210.26%125.00%
naoya horiguchinaoya horiguchi108.55%125.00%

static int mincore_unmapped_range(unsigned long addr, unsigned long end, struct mm_walk *walk) { walk->private += __mincore_unmapped_range(addr, end, walk->vma, walk->private); return 0; }


naoya horiguchinaoya horiguchi3687.80%150.00%
johannes weinerjohannes weiner512.20%150.00%

static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, struct mm_walk *walk) { spinlock_t *ptl; struct vm_area_struct *vma = walk->vma; pte_t *ptep; unsigned char *vec = walk->private; int nr = (end - addr) >> PAGE_SHIFT; ptl = pmd_trans_huge_lock(pmd, vma); if (ptl) { memset(vec, 1, nr); spin_unlock(ptl); goto out; } if (pmd_trans_unstable(pmd)) { __mincore_unmapped_range(addr, end, vma, vec); goto out; } ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); for (; addr != end; ptep++, addr += PAGE_SIZE) { pte_t pte = *ptep; if (pte_none(pte)) __mincore_unmapped_range(addr, addr + PAGE_SIZE, vma, vec); else if (pte_present(pte)) *vec = 1; else { /* pte is a swap entry */ swp_entry_t entry = pte_to_swp_entry(pte); if (non_swap_entry(entry)) { /* * migration or hwpoison entries are always * uptodate */ *vec = 1; } else { #ifdef CONFIG_SWAP *vec = mincore_page(swap_address_space(entry), entry.val); #else WARN_ON(1); *vec = 1; #endif } } vec++; } pte_unmap_unlock(ptep - 1, ptl); out: walk->private += nr; cond_resched(); return 0; }


naoya horiguchinaoya horiguchi11742.70%18.33%
nick pigginnick piggin9133.21%216.67%
johannes weinerjohannes weiner4917.88%433.33%
kirill a. shutemovkirill a. shutemov93.28%216.67%
shaohua lishaohua li41.46%18.33%
weijie yangweijie yang20.73%18.33%
linus torvaldslinus torvalds20.73%18.33%

/* * Do a chunk of "sys_mincore()". We've already checked * all the arguments, we hold the mmap semaphore: we should * just return the amount of info we're asked for. */
static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *vec) { struct vm_area_struct *vma; unsigned long end; int err; struct mm_walk mincore_walk = { .pmd_entry = mincore_pte_range, .pte_hole = mincore_unmapped_range, .hugetlb_entry = mincore_hugetlb, .private = vec, }; vma = find_vma(current->mm, addr); if (!vma || addr < vma->vm_start) return -ENOMEM; = vma->vm_mm; end = min(vma->vm_end, addr + (pages << PAGE_SHIFT)); err = walk_page_range(addr, end, &mincore_walk); if (err < 0) return err; return (end - addr) >> PAGE_SHIFT; }


johannes weinerjohannes weiner7755.80%342.86%
naoya horiguchinaoya horiguchi5136.96%114.29%
nick pigginnick piggin75.07%228.57%
linus torvaldslinus torvalds32.17%114.29%

/* * The mincore(2) system call. * * mincore() returns the memory residency status of the pages in the * current process's address space specified by [addr, addr + len). * The status is returned in a vector of bytes. The least significant * bit of each byte is 1 if the referenced page is in memory, otherwise * it is zero. * * Because the status of a page can change after mincore() checks it * but before it returns to the application, the returned vector may * contain stale information. Only locked pages are guaranteed to * remain in memory. * * return values: * zero - success * -EFAULT - vec points to an illegal address * -EINVAL - addr is not a multiple of PAGE_SIZE * -ENOMEM - Addresses in the range [addr, addr + len] are * invalid for the address space of this process, or * specify one or more pages which are not currently * mapped * -EAGAIN - A kernel resource was temporarily unavailable. */ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len, unsigned char __user *, vec) { long retval; unsigned long pages; unsigned char *tmp; /* Check the start address: needs to be page-aligned.. */ if (start & ~PAGE_MASK) return -EINVAL; /* ..and we need to be passed a valid user-space range */ if (!access_ok(VERIFY_READ, (void __user *) start, len)) return -ENOMEM; /* This also avoids any overflows on PAGE_ALIGN */ pages = len >> PAGE_SHIFT; pages += (offset_in_page(len)) != 0; if (!access_ok(VERIFY_WRITE, vec, pages)) return -EFAULT; tmp = (void *) __get_free_page(GFP_USER); if (!tmp) return -EAGAIN; retval = 0; while (pages) { /* * Do at most PAGE_SIZE entries per iteration, due to * the temporary buffer size. */ down_read(&current->mm->mmap_sem); retval = do_mincore(start, min(pages, PAGE_SIZE), tmp); up_read(&current->mm->mmap_sem); if (retval <= 0) break; if (copy_to_user(vec, tmp, retval)) { retval = -EFAULT; break; } pages -= retval; vec += retval; start += retval << PAGE_SHIFT; retval = 0; } free_page((unsigned long) tmp); return retval; }

Overall Contributors

johannes weinerjohannes weiner33231.86%517.86%
naoya horiguchinaoya horiguchi27826.68%27.14%
linus torvaldslinus torvalds21020.15%310.71%
nick pigginnick piggin12311.80%414.29%
hugh dickinshugh dickins282.69%13.57%
david howellsdavid howells161.54%13.57%
heiko carstensheiko carstens161.54%13.57%
kirill a. shutemovkirill a. shutemov131.25%414.29%
gordon jingordon jin80.77%13.57%
shaohua lishaohua li70.67%13.57%
alexander kuleshovalexander kuleshov30.29%13.57%
arnd bergmannarnd bergmann30.29%13.57%
tejun heotejun heo20.19%13.57%
weijie yangweijie yang20.19%13.57%
oleg nesterovoleg nesterov10.10%13.57%
Directory: mm
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