Updated kernel (2.6.27.41).

[ipfire-2.x.git] / src / patches / suse-2.6.27.39 / patches.fixes / dm-path-selector-ref-count

diff --git a/src/patches/suse-2.6.27.39/patches.fixes/dm-path-selector-ref-count b/src/patches/suse-2.6.27.39/patches.fixes/dm-path-selector-ref-count
deleted file mode 100644 (file)
index 8696401..0000000
--- a/src/patches/suse-2.6.27.39/patches.fixes/dm-path-selector-ref-count
+++ /dev/null
@@ -1,124 +0,0 @@
-From: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com>
-Subject: dm-path-selector: fix refcount corruption
-
-Hi,
-
-Refcounting of path-selector module is not safe in SMP environment.
-The counter may corrupt and trigger BUG() like this:
-  kernel BUG at linux-2.6.29-rc3/drivers/md/dm-path-selector.c:90!
-though it's rare under normal usage.
-
-The bug is here:
-  void dm_put_path_selector(struct path_selector_type *pst)
-  {
-  ...
-        down_read(&_ps_lock);
-        psi = __find_path_selector_type(pst->name);
-        if (!psi)
-                goto out;
-
-        if (--psi->use == 0)
-                module_put(psi->pst.module);
-
-        BUG_ON(psi->use < 0);
-
-The code manipulates the counter without exclusive lock or atomic ops.
-So if 2 processors come in, the counter may corrupt.
-
-While it could be fixed using atomic ops for the counter manipulation,
-we can just drop the 'use' counter like Cheng Renquan did for dm-target:
-https://www.redhat.com/archives/dm-devel/2008-December/msg00075.html
-
-(Actually, without his patch, dm-target.c hits the same problem.)
-
-Signed-off-by: Hannes Reinecke <hare@suse.de>
-
--- 
-Jun'ichi Nomura, NEC Corporation
-
-
-Fix refcount corruption in dm-path-selector
-
-Refcounting with non-atomic ops under shared lock will corrupt the counter
-in multi-processor system and may trigger BUG_ON().
-Use module refcount.
-# same approach as dm-target-use-module-refcount-directly.patch here
-# https://www.redhat.com/archives/dm-devel/2008-December/msg00075.html
-
-Typical oops:
-  kernel BUG at linux-2.6.29-rc3/drivers/md/dm-path-selector.c:90!
-  Pid: 11148, comm: dmsetup Not tainted 2.6.29-rc3-nm #1
-  dm_put_path_selector+0x4d/0x61 [dm_multipath]
-  Call Trace:
-   [<ffffffffa031d3f9>] free_priority_group+0x33/0xb3 [dm_multipath]
-   [<ffffffffa031d4aa>] free_multipath+0x31/0x67 [dm_multipath]
-   [<ffffffffa031d50d>] multipath_dtr+0x2d/0x32 [dm_multipath]
-   [<ffffffffa015d6c2>] dm_table_destroy+0x64/0xd8 [dm_mod]
-   [<ffffffffa015b73a>] __unbind+0x46/0x4b [dm_mod]
-   [<ffffffffa015b79f>] dm_swap_table+0x60/0x14d [dm_mod]
-   [<ffffffffa015f963>] dev_suspend+0xfd/0x177 [dm_mod]
-   [<ffffffffa0160250>] dm_ctl_ioctl+0x24c/0x29c [dm_mod]
-   [<ffffffff80288cd3>] ? get_page_from_freelist+0x49c/0x61d
-   [<ffffffffa015f866>] ? dev_suspend+0x0/0x177 [dm_mod]
-   [<ffffffff802bf05c>] vfs_ioctl+0x2a/0x77
-   [<ffffffff802bf4f1>] do_vfs_ioctl+0x448/0x4a0
-   [<ffffffff802bf5a0>] sys_ioctl+0x57/0x7a
-   [<ffffffff8020c05b>] system_call_fastpath+0x16/0x1b
-
-Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
----
- drivers/md/dm-path-selector.c |   21 +++------------------
- 1 file changed, 3 insertions(+), 18 deletions(-)
-
---- a/drivers/md/dm-path-selector.c
-+++ b/drivers/md/dm-path-selector.c
-@@ -16,9 +16,7 @@
- 
- struct ps_internal {
-       struct path_selector_type pst;
--
-       struct list_head list;
--      long use;
- };
- 
- #define pst_to_psi(__pst) container_of((__pst), struct ps_internal, pst)
-@@ -44,12 +42,8 @@ static struct ps_internal *get_path_sele
- 
-       down_read(&_ps_lock);
-       psi = __find_path_selector_type(name);
--      if (psi) {
--              if ((psi->use == 0) && !try_module_get(psi->pst.module))
--                      psi = NULL;
--              else
--                      psi->use++;
--      }
-+      if (psi && !try_module_get(psi->pst.module))
-+              psi = NULL;
-       up_read(&_ps_lock);
- 
-       return psi;
-@@ -83,11 +77,7 @@ void dm_put_path_selector(struct path_se
-       if (!psi)
-               goto out;
- 
--      if (--psi->use == 0)
--              module_put(psi->pst.module);
--
--      BUG_ON(psi->use < 0);
--
-+      module_put(psi->pst.module);
- out:
-       up_read(&_ps_lock);
- }
-@@ -135,11 +125,6 @@ int dm_unregister_path_selector(struct p
-               return -EINVAL;
-       }
- 
--      if (psi->use) {
--              up_write(&_ps_lock);
--              return -ETXTBSY;
--      }
--
-       list_del(&psi->list);
- 
-       up_write(&_ps_lock);