kernel/linux.git/fs/dlm/memory.c, branch v6.19.11

dlm: move lkb xarray lookup out of lock

2024-08-08T20:15:08+00:00

This patch moves the xarray lookup functionality for the lkb out of the ls_lkbxa_lock read lock handling. We can do that as the xarray should be possible to access lockless in case of reader like xa_load(). We confirm under ls_lkbxa_lock that the lkb is still part of the data structure and take a reference when its still part of ls_lkbxa to avoid being freed after doing the lookup. To do a check if the lkb is still part of the ls_lkbxa data structure we use a kref_read() as the last put will remove it from the ls_lkbxa data structure and any reference taken means it is still part of ls_lkbxa. A similar approach was done with the DLM rsb rhashtable just with a flag instead of the refcounter because the refcounter has a slightly different meaning. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

dlm: cleanup memory allocation helpers

2024-08-08T20:14:41+00:00

This patch removes a unnecessary parameter from DLM memory allocation helpers and reduce some functions by just directly reply the pointer address of the allocated memory. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

dlm: add rcu_barrier before destroy kmem cache

2024-06-13T17:48:46+00:00

In the case we trigger dlm_free_rsb() that does a call_rcu() and the responding kfree() of res_lvbptr and a kmem_cache_free() of the rsb pointer we need to wait until this pending operation is done before calling kmem_cache_destroy(). We doing that by using rcu_barrier() that waits until all pending call_rcu() are done. This avoids that kmem_cache_destroy() complains about active objects around that are not being freed yet by call_rcu(). There is currently more discussions about to make this behaviour better, see: https://lore.kernel.org/netdev/20240609082726.32742-1-Julia.Lawall@inria.fr/ However this is only for call_rcu() if the callback calls kmem_cache_destroy() only to replace it by kfree_rcu() call which has currently some issue. This isn't our case because we also free the res_lvbptr if being set. For our case, to avoid the above race rcu_barrier() should be used before calling kmem_cache_destroy() to be sure that there are no active objects around. This is exactly what net/batman-adv is also doing before calling their kmem_cache_destroy() in module unloading. Fixes: 01fdeca1cc2d ("dlm: use rcu to avoid an extra rsb struct lookup") Signed-off-by: Alexander Aring Signed-off-by: David Teigland

dlm: use rcu to avoid an extra rsb struct lookup

2024-06-10T20:26:03+00:00

Use rcu to free rsb structs, and hold the rcu read lock while looking up rsb structs. This allows us to avoid an extra hash table lookup for an rsb. A new rsb flag HASHED is added which is set while the rsb is in the hash table. This flag is checked in place of repeating the hash table lookup. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

dlm: switch to GFP_ATOMIC in dlm allocations

2024-04-09T16:43:49+00:00

Replace GFP_NOFS with GFP_ATOMIC. Also stop using idr_preload which uses a non-bh spin_lock. This is further preparation for softirq message processing. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

dlm: remove allocation parameter in msg allocation

2024-04-09T14:58:14+00:00

Remove the context parameter for message allocations and always use GFP_ATOMIC. This prepares for softirq message processing. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

dlm: remove callback reference counting

2024-04-01T18:31:13+00:00

Get rid of the unnecessary refcounting on callback structs. Copy interesting callback info into the lkb struct rather than maintaining pointers to callback structs from the lkb. This goes back to the way things were done prior to commit 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks"). Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: change dflags to use atomic bits

2023-03-06T21:49:07+00:00

Currently manipulating lkb_dflags assumes to held the rsb lock assigned to the lkb. This is held by dlm message processing after certain time to lookup the right rsb from the received lkb message id. For user space locks flags, which is currently the only use case for lkb_dflags, flags are also being set during dlm character device handling without holding the rsb lock. To minimize the risk that bit operations are getting corrupted we switch to atomic bit operations. This patch will also introduce helpers to snapshot atomic bit values in an non atomic way. There might be still issues with the flag handling e.g. running in case of manipulating bit ops and snapshot them at the same time, but this patch minimize them and will start to use atomic bit operations. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: store lkb distributed flags into own value

2023-03-06T21:49:07+00:00

This patch stores lkb distributed flags value in an separate value instead of sharing internal and distributed flags in lkb->lkb_flags value. This has the advantage to not mask/write back flag values in receive_flags() functionality. The dlm debug_fs does not provide the distributed flags anymore, those can be added in future. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: fix return value check in dlm_memory_init()

2023-01-05T21:37:51+00:00

It should check 'cb_cache', after calling kmem_cache_create("dlm_cb"). Fixes: 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks") Signed-off-by: Yang Yingliang Signed-off-by: David Teigland