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| author | Jason Gunthorpe <jgg@mellanox.com> | 2018-08-16 23:13:03 +0300 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@mellanox.com> | 2018-08-16 23:21:29 +0300 |
| commit | 0a3173a5f09bc58a3638ecfd0a80bdbae55e123c (patch) | |
| tree | d6c0bc84863cca54dfbde3b7463e5d49c82af9f1 /Documentation/RCU/whatisRCU.txt | |
| parent | 92f4e77c85918eab5e5803d7e28ab89a7e6bd3a2 (diff) | |
| parent | 5c60a7389d795e001c8748b458eb76e3a5b6008c (diff) | |
| download | linux-0a3173a5f09bc58a3638ecfd0a80bdbae55e123c.tar.xz | |
Merge branch 'linus/master' into rdma.git for-next
rdma.git merge resolution for the 4.19 merge window
Conflicts:
drivers/infiniband/core/rdma_core.c
- Use the rdma code and revise with the new spelling for
atomic_fetch_add_unless
drivers/nvme/host/rdma.c
- Replace max_sge with max_send_sge in new blk code
drivers/nvme/target/rdma.c
- Use the blk code and revise to use NULL for ib_post_recv when
appropriate
- Replace max_sge with max_recv_sge in new blk code
net/rds/ib_send.c
- Use the net code and revise to use NULL for ib_post_recv when
appropriate
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'Documentation/RCU/whatisRCU.txt')
| -rw-r--r-- | Documentation/RCU/whatisRCU.txt | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt index 65eb856526b7..c2a7facf7ff9 100644 --- a/Documentation/RCU/whatisRCU.txt +++ b/Documentation/RCU/whatisRCU.txt @@ -588,6 +588,7 @@ It is extremely simple: void synchronize_rcu(void) { write_lock(&rcu_gp_mutex); + smp_mb__after_spinlock(); write_unlock(&rcu_gp_mutex); } @@ -609,12 +610,15 @@ don't forget about them when submitting patches making use of RCU!] The rcu_read_lock() and rcu_read_unlock() primitive read-acquire and release a global reader-writer lock. The synchronize_rcu() -primitive write-acquires this same lock, then immediately releases -it. This means that once synchronize_rcu() exits, all RCU read-side -critical sections that were in progress before synchronize_rcu() was -called are guaranteed to have completed -- there is no way that -synchronize_rcu() would have been able to write-acquire the lock -otherwise. +primitive write-acquires this same lock, then releases it. This means +that once synchronize_rcu() exits, all RCU read-side critical sections +that were in progress before synchronize_rcu() was called are guaranteed +to have completed -- there is no way that synchronize_rcu() would have +been able to write-acquire the lock otherwise. The smp_mb__after_spinlock() +promotes synchronize_rcu() to a full memory barrier in compliance with +the "Memory-Barrier Guarantees" listed in: + + Documentation/RCU/Design/Requirements/Requirements.html. It is possible to nest rcu_read_lock(), since reader-writer locks may be recursively acquired. Note also that rcu_read_lock() is immune @@ -816,11 +820,13 @@ RCU list traversal: list_next_rcu list_for_each_entry_rcu list_for_each_entry_continue_rcu + list_for_each_entry_from_rcu hlist_first_rcu hlist_next_rcu hlist_pprev_rcu hlist_for_each_entry_rcu hlist_for_each_entry_rcu_bh + hlist_for_each_entry_from_rcu hlist_for_each_entry_continue_rcu hlist_for_each_entry_continue_rcu_bh hlist_nulls_first_rcu |