Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus-1

* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6: (9356 commits)
  [media] rc: update for bitop name changes
  fs: simplify iget & friends
  fs: pull inode->i_lock up out of writeback_single_inode
  fs: rename inode_lock to inode_hash_lock
  fs: move i_wb_list out from under inode_lock
  fs: move i_sb_list out from under inode_lock
  fs: remove inode_lock from iput_final and prune_icache
  fs: Lock the inode LRU list separately
  fs: factor inode disposal
  fs: protect inode->i_state with inode->i_lock
  lib, arch: add filter argument to show_mem and fix private implementations
  SLUB: Write to per cpu data when allocating it
  slub: Fix debugobjects with lockless fastpath
  autofs4: Do not potentially dereference NULL pointer returned by fget() in autofs_dev_ioctl_setpipefd()
  autofs4 - remove autofs4_lock
  autofs4 - fix d_manage() return on rcu-walk
  autofs4 - fix autofs4_expire_indirect() traversal
  autofs4 - fix dentry leak in autofs4_expire_direct()
  autofs4 - reinstate last used update on access
  vfs - check non-mountpoint dentry might block in __follow_mount_rcu()
  ...

NOTE!

This merge commit was created to fix compilation error. The block
tree was merged upstream and removed the 'elv_queue_empty()'
function which the new 'mtdswap' driver is using. So a simple
merge of the mtd tree with upstream does not compile. And the
mtd tree has already be published, so re-basing it is not an option.

To fix this unfortunate situation, I had to merge upstream into the
mtd-2.6.git tree without committing, put the fixup patch on top of
this, and then commit this. The result is that we do not have commits
which do not compile.

In other words, this merge commit "merges" 3 things: the MTD tree, the
upstream tree, and the fixup patch.

1 files changed, 101 insertions, 4 deletions

diff --git a/Documentation/vm/page-types.c b/Documentation/vm/page-types.c
index cc96ee2..7445caa 100644
--- a/Documentation/vm/page-types.c
+++ b/Documentation/vm/page-types.c
@@ -32,8 +32,20 @@
 #include <sys/types.h>
 #include <sys/errno.h>
 #include <sys/fcntl.h>
+#include <sys/mount.h>
+#include <sys/statfs.h>
+#include "../../include/linux/magic.h"
 
 
+#ifndef MAX_PATH
+# define MAX_PATH 256
+#endif
+
+#ifndef STR
+# define _STR(x) #x
+# define STR(x) _STR(x)
+#endif
+
 /*
  * pagemap kernel ABI bits
  */
@@ -152,6 +164,12 @@ static const char *page_flag_names[] = {
 };
 
 
+static const char *debugfs_known_mountpoints[] = {
+	"/sys/kernel/debug",
+	"/debug",
+	0,
+};
+
 /*
  * data structures
  */
@@ -184,7 +202,7 @@ static int		kpageflags_fd;
 static int		opt_hwpoison;
 static int		opt_unpoison;
 
-static const char	hwpoison_debug_fs[] = "/debug/hwpoison";
+static char		hwpoison_debug_fs[MAX_PATH+1];
 static int		hwpoison_inject_fd;
 static int		hwpoison_forget_fd;
 
@@ -464,21 +482,100 @@ static uint64_t kpageflags_flags(uint64_t flags)
 	return flags;
 }
 
+/* verify that a mountpoint is actually a debugfs instance */
+static int debugfs_valid_mountpoint(const char *debugfs)
+{
+	struct statfs st_fs;
+
+	if (statfs(debugfs, &st_fs) < 0)
+		return -ENOENT;
+	else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
+		return -ENOENT;
+
+	return 0;
+}
+
+/* find the path to the mounted debugfs */
+static const char *debugfs_find_mountpoint(void)
+{
+	const char **ptr;
+	char type[100];
+	FILE *fp;
+
+	ptr = debugfs_known_mountpoints;
+	while (*ptr) {
+		if (debugfs_valid_mountpoint(*ptr) == 0) {
+			strcpy(hwpoison_debug_fs, *ptr);
+			return hwpoison_debug_fs;
+		}
+		ptr++;
+	}
+
+	/* give up and parse /proc/mounts */
+	fp = fopen("/proc/mounts", "r");
+	if (fp == NULL)
+		perror("Can't open /proc/mounts for read");
+
+	while (fscanf(fp, "%*s %"
+		      STR(MAX_PATH)
+		      "s %99s %*s %*d %*d\n",
+		      hwpoison_debug_fs, type) == 2) {
+		if (strcmp(type, "debugfs") == 0)
+			break;
+	}
+	fclose(fp);
+
+	if (strcmp(type, "debugfs") != 0)
+		return NULL;
+
+	return hwpoison_debug_fs;
+}
+
+/* mount the debugfs somewhere if it's not mounted */
+
+static void debugfs_mount(void)
+{
+	const char **ptr;
+
+	/* see if it's already mounted */
+	if (debugfs_find_mountpoint())
+		return;
+
+	ptr = debugfs_known_mountpoints;
+	while (*ptr) {
+		if (mount(NULL, *ptr, "debugfs", 0, NULL) == 0) {
+			/* save the mountpoint */
+			strcpy(hwpoison_debug_fs, *ptr);
+			break;
+		}
+		ptr++;
+	}
+
+	if (*ptr == NULL) {
+		perror("mount debugfs");
+		exit(EXIT_FAILURE);
+	}
+}
+
 /*
  * page actions
  */
 
 static void prepare_hwpoison_fd(void)
 {
-	char buf[100];
+	char buf[MAX_PATH + 1];
+
+	debugfs_mount();
 
 	if (opt_hwpoison && !hwpoison_inject_fd) {
-		sprintf(buf, "%s/corrupt-pfn", hwpoison_debug_fs);
+		snprintf(buf, MAX_PATH, "%s/hwpoison/corrupt-pfn",
+			hwpoison_debug_fs);
 		hwpoison_inject_fd = checked_open(buf, O_WRONLY);
 	}
 
 	if (opt_unpoison && !hwpoison_forget_fd) {
-		sprintf(buf, "%s/unpoison-pfn", hwpoison_debug_fs);
+		snprintf(buf, MAX_PATH, "%s/hwpoison/unpoison-pfn",
+			hwpoison_debug_fs);
 		hwpoison_forget_fd = checked_open(buf, O_WRONLY);
 	}
 }