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author | Vishal Verma <vishal.l.verma@intel.com> | 2024-04-30 11:44:24 -0600 |
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committer | Andrew Morton <akpm@linux-foundation.org> | 2024-05-07 10:37:00 -0700 |
commit | 6f6544f27e41f9d7dca55c288f12175a9c48dfe2 (patch) | |
tree | df0e1c6557cbc3c052cbd82726dc5f996fc16347 /drivers/dax | |
parent | c14c647bbe23fd96f6bffcc122b9c6c8c46c7928 (diff) | |
download | linux-stable-6f6544f27e41f9d7dca55c288f12175a9c48dfe2.tar.gz linux-stable-6f6544f27e41f9d7dca55c288f12175a9c48dfe2.tar.bz2 linux-stable-6f6544f27e41f9d7dca55c288f12175a9c48dfe2.zip |
dax/bus.c: fix locking for unregister_dax_dev / unregister_dax_mapping paths
Commit c05ae9d85b47 ("dax/bus.c: replace driver-core lock usage by a local
rwsem") aimed to undo device_lock() abuses for protecting changes to
dax-driver internal data-structures like the dax_region resource tree to
device-dax-instance range structures. However, the device_lock() was
legitimately enforcing that devices to be deleted were not current
actively attached to any driver nor assigned any capacity from the region.
As a result of the device_lock restoration in delete_store(), the
conditional locking in unregister_dev_dax() and unregister_dax_mapping()
can be removed.
Link: https://lkml.kernel.org/r/20240430-vv-dax_abi_fixes-v3-2-e3dcd755774c@intel.com
Fixes: c05ae9d85b47 ("dax/bus.c: replace driver-core lock usage by a local rwsem")
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Reported-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'drivers/dax')
-rw-r--r-- | drivers/dax/bus.c | 42 |
1 files changed, 8 insertions, 34 deletions
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 7924dd542a13..e2c7354ce328 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -465,26 +465,17 @@ static void free_dev_dax_ranges(struct dev_dax *dev_dax) trim_dev_dax_range(dev_dax); } -static void __unregister_dev_dax(void *dev) +static void unregister_dev_dax(void *dev) { struct dev_dax *dev_dax = to_dev_dax(dev); dev_dbg(dev, "%s\n", __func__); + down_write(&dax_region_rwsem); kill_dev_dax(dev_dax); device_del(dev); free_dev_dax_ranges(dev_dax); put_device(dev); -} - -static void unregister_dev_dax(void *dev) -{ - if (rwsem_is_locked(&dax_region_rwsem)) - return __unregister_dev_dax(dev); - - if (WARN_ON_ONCE(down_write_killable(&dax_region_rwsem) != 0)) - return; - __unregister_dev_dax(dev); up_write(&dax_region_rwsem); } @@ -560,15 +551,10 @@ static ssize_t delete_store(struct device *dev, struct device_attribute *attr, if (!victim) return -ENXIO; - rc = down_write_killable(&dax_region_rwsem); - if (rc) - return rc; - rc = down_write_killable(&dax_dev_rwsem); - if (rc) { - up_write(&dax_region_rwsem); - return rc; - } + device_lock(dev); + device_lock(victim); dev_dax = to_dev_dax(victim); + down_write(&dax_dev_rwsem); if (victim->driver || dev_dax_size(dev_dax)) rc = -EBUSY; else { @@ -589,11 +575,12 @@ static ssize_t delete_store(struct device *dev, struct device_attribute *attr, rc = -EBUSY; } up_write(&dax_dev_rwsem); + device_unlock(victim); /* won the race to invalidate the device, clean it up */ if (do_del) devm_release_action(dev, unregister_dev_dax, victim); - up_write(&dax_region_rwsem); + device_unlock(dev); put_device(victim); return rc; @@ -705,7 +692,7 @@ static void dax_mapping_release(struct device *dev) put_device(parent); } -static void __unregister_dax_mapping(void *data) +static void unregister_dax_mapping(void *data) { struct device *dev = data; struct dax_mapping *mapping = to_dax_mapping(dev); @@ -713,25 +700,12 @@ static void __unregister_dax_mapping(void *data) dev_dbg(dev, "%s\n", __func__); - lockdep_assert_held_write(&dax_region_rwsem); - dev_dax->ranges[mapping->range_id].mapping = NULL; mapping->range_id = -1; device_unregister(dev); } -static void unregister_dax_mapping(void *data) -{ - if (rwsem_is_locked(&dax_region_rwsem)) - return __unregister_dax_mapping(data); - - if (WARN_ON_ONCE(down_write_killable(&dax_region_rwsem) != 0)) - return; - __unregister_dax_mapping(data); - up_write(&dax_region_rwsem); -} - static struct dev_dax_range *get_dax_range(struct device *dev) { struct dax_mapping *mapping = to_dax_mapping(dev); |