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| author | Kiyoshi Ueda <[email protected]> | 2010-08-12 04:13:55 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <[email protected]> | 2010-08-12 04:13:55 +0100 |
| commit | 98f332855effef02aeb738e4d62e9a5b903c52fd (patch) | |
| tree | b10d7f632022415ddb047c2bacbaa1f861a76161 /lib/debugobjects.c | |
| parent | abdc568b0540bec6d3e0afebac496adef1189b77 (diff) | |
dm ioctl: release _hash_lock between devices in remove_all
This patch changes dm_hash_remove_all() to release _hash_lock when
removing a device. After removing the device, dm_hash_remove_all()
takes _hash_lock and searches the hash from scratch again.
This patch is a preparation for the next patch, which changes device
deletion code to wait for md reference to be 0. Without this patch,
the wait in the next patch may cause AB-BA deadlock:
CPU0 CPU1
-----------------------------------------------------------------------
dm_hash_remove_all()
down_write(_hash_lock)
table_status()
md = find_device()
dm_get(md)
<increment md->holders>
dm_get_live_or_inactive_table()
dm_get_inactive_table()
down_write(_hash_lock)
<in the md deletion code>
<wait for md->holders to be 0>
Signed-off-by: Kiyoshi Ueda <[email protected]>
Signed-off-by: Jun'ichi Nomura <[email protected]>
Cc: [email protected]
Signed-off-by: Alasdair G Kergon <[email protected]>
Diffstat (limited to 'lib/debugobjects.c')
0 files changed, 0 insertions, 0 deletions