Documentation/vm/page-types.c: auto debugfs mount for hwpoison operation
page-types.c doesn't supply a way to specify the debugfs path and the original debugfs path is not usual on most machines. This patch supplies a way to auto mount debugfs if needed. This patch is heavily inspired by tools/perf/utils/debugfs.c [akpm@linux-foundation.org: make functions static] [akpm@linux-foundation.org: fix debugfs_mount() signature] Signed-off-by: Chen Gong <gong.chen@linux.intel.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1 changed files with 101 additions and 4 deletions
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@ -32,8 +32,20 @@
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#include <sys/types.h>
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#include <sys/types.h>
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#include <sys/errno.h>
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#include <sys/errno.h>
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#include <sys/fcntl.h>
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#include <sys/fcntl.h>
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#include <sys/mount.h>
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#include <sys/statfs.h>
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#include "../../include/linux/magic.h"
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#ifndef MAX_PATH
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# define MAX_PATH 256
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#endif
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#ifndef STR
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# define _STR(x) #x
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# define STR(x) _STR(x)
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#endif
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/*
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/*
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* pagemap kernel ABI bits
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* pagemap kernel ABI bits
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*/
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*/
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@ -152,6 +164,12 @@ static const char *page_flag_names[] = {
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};
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};
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static const char *debugfs_known_mountpoints[] = {
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"/sys/kernel/debug",
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"/debug",
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0,
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};
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/*
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/*
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* data structures
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* data structures
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*/
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*/
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@ -184,7 +202,7 @@ static int kpageflags_fd;
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static int opt_hwpoison;
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static int opt_hwpoison;
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static int opt_unpoison;
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static int opt_unpoison;
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static const char hwpoison_debug_fs[] = "/debug/hwpoison";
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static char hwpoison_debug_fs[MAX_PATH+1];
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static int hwpoison_inject_fd;
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static int hwpoison_inject_fd;
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static int hwpoison_forget_fd;
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static int hwpoison_forget_fd;
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@ -464,21 +482,100 @@ static uint64_t kpageflags_flags(uint64_t flags)
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return flags;
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return flags;
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}
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}
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/* verify that a mountpoint is actually a debugfs instance */
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static int debugfs_valid_mountpoint(const char *debugfs)
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{
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struct statfs st_fs;
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if (statfs(debugfs, &st_fs) < 0)
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return -ENOENT;
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else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
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return -ENOENT;
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return 0;
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}
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/* find the path to the mounted debugfs */
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static const char *debugfs_find_mountpoint(void)
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{
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const char **ptr;
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char type[100];
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FILE *fp;
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ptr = debugfs_known_mountpoints;
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while (*ptr) {
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if (debugfs_valid_mountpoint(*ptr) == 0) {
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strcpy(hwpoison_debug_fs, *ptr);
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return hwpoison_debug_fs;
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}
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ptr++;
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}
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/* give up and parse /proc/mounts */
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fp = fopen("/proc/mounts", "r");
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if (fp == NULL)
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perror("Can't open /proc/mounts for read");
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while (fscanf(fp, "%*s %"
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STR(MAX_PATH)
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"s %99s %*s %*d %*d\n",
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hwpoison_debug_fs, type) == 2) {
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if (strcmp(type, "debugfs") == 0)
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break;
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}
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fclose(fp);
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if (strcmp(type, "debugfs") != 0)
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return NULL;
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return hwpoison_debug_fs;
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}
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/* mount the debugfs somewhere if it's not mounted */
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static void debugfs_mount(void)
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{
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const char **ptr;
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/* see if it's already mounted */
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if (debugfs_find_mountpoint())
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return;
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ptr = debugfs_known_mountpoints;
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while (*ptr) {
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if (mount(NULL, *ptr, "debugfs", 0, NULL) == 0) {
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/* save the mountpoint */
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strcpy(hwpoison_debug_fs, *ptr);
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break;
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}
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ptr++;
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}
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if (*ptr == NULL) {
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perror("mount debugfs");
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exit(EXIT_FAILURE);
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}
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}
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/*
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/*
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* page actions
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* page actions
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*/
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*/
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static void prepare_hwpoison_fd(void)
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static void prepare_hwpoison_fd(void)
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{
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{
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char buf[100];
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char buf[MAX_PATH + 1];
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debugfs_mount();
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if (opt_hwpoison && !hwpoison_inject_fd) {
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if (opt_hwpoison && !hwpoison_inject_fd) {
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sprintf(buf, "%s/corrupt-pfn", hwpoison_debug_fs);
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snprintf(buf, MAX_PATH, "%s/hwpoison/corrupt-pfn",
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hwpoison_debug_fs);
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hwpoison_inject_fd = checked_open(buf, O_WRONLY);
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hwpoison_inject_fd = checked_open(buf, O_WRONLY);
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}
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}
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if (opt_unpoison && !hwpoison_forget_fd) {
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if (opt_unpoison && !hwpoison_forget_fd) {
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sprintf(buf, "%s/unpoison-pfn", hwpoison_debug_fs);
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snprintf(buf, MAX_PATH, "%s/hwpoison/unpoison-pfn",
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hwpoison_debug_fs);
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hwpoison_forget_fd = checked_open(buf, O_WRONLY);
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hwpoison_forget_fd = checked_open(buf, O_WRONLY);
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}
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}
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}
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}
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