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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-05-12 15:56:35 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-06-08 18:52:41 -0700
commit41a2901e7d220875752a8c870e0b53288a578c20 (patch)
tree7fee0c0fb4e4de059050c0003c370042bb832ffc /Documentation/RCU
parentc4a09ff752e164c020bced6513e2008f992a02e6 (diff)
downloadlinux-41a2901e7d220875752a8c870e0b53288a578c20.tar.bz2
rcu: Remove SPARSE_RCU_POINTER Kconfig option
The sparse-based checking for non-RCU accesses to RCU-protected pointers has been around for a very long time, and it is now the only type of sparse-based checking that is optional. This commit therefore makes it unconditional. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Fengguang Wu <fengguang.wu@intel.com>
Diffstat (limited to 'Documentation/RCU')
-rw-r--r--Documentation/RCU/Design/Requirements/Requirements.html9
-rw-r--r--Documentation/RCU/checklist.txt8
2 files changed, 7 insertions, 10 deletions
diff --git a/Documentation/RCU/Design/Requirements/Requirements.html b/Documentation/RCU/Design/Requirements/Requirements.html
index 8c94fc1d1c84..0e6550a8c926 100644
--- a/Documentation/RCU/Design/Requirements/Requirements.html
+++ b/Documentation/RCU/Design/Requirements/Requirements.html
@@ -559,9 +559,7 @@ The <tt>rcu_access_pointer()</tt> on line&nbsp;6 is similar to
For <tt>remove_gp_synchronous()</tt>, as long as all modifications
to <tt>gp</tt> are carried out while holding <tt>gp_lock</tt>,
the above optimizations are harmless.
- However,
- with <tt>CONFIG_SPARSE_RCU_POINTER=y</tt>,
- <tt>sparse</tt> will complain if you
+ However, <tt>sparse</tt> will complain if you
define <tt>gp</tt> with <tt>__rcu</tt> and then
access it without using
either <tt>rcu_access_pointer()</tt> or <tt>rcu_dereference()</tt>.
@@ -1978,9 +1976,8 @@ guard against mishaps and misuse:
and <tt>rcu_dereference()</tt>, perhaps (incorrectly)
substituting a simple assignment.
To catch this sort of error, a given RCU-protected pointer may be
- tagged with <tt>__rcu</tt>, after which running sparse
- with <tt>CONFIG_SPARSE_RCU_POINTER=y</tt> will complain
- about simple-assignment accesses to that pointer.
+ tagged with <tt>__rcu</tt>, after which sparse
+ will complain about simple-assignment accesses to that pointer.
Arnd Bergmann made me aware of this requirement, and also
supplied the needed
<a href="https://lwn.net/Articles/376011/">patch series</a>.
diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index 877947130ebe..6beda556faf3 100644
--- a/Documentation/RCU/checklist.txt
+++ b/Documentation/RCU/checklist.txt
@@ -413,11 +413,11 @@ over a rather long period of time, but improvements are always welcome!
read-side critical sections. It is the responsibility of the
RCU update-side primitives to deal with this.
-17. Use CONFIG_PROVE_RCU, CONFIG_DEBUG_OBJECTS_RCU_HEAD, and the
- __rcu sparse checks (enabled by CONFIG_SPARSE_RCU_POINTER) to
- validate your RCU code. These can help find problems as follows:
+17. Use CONFIG_PROVE_LOCKING, CONFIG_DEBUG_OBJECTS_RCU_HEAD, and the
+ __rcu sparse checks to validate your RCU code. These can help
+ find problems as follows:
- CONFIG_PROVE_RCU: check that accesses to RCU-protected data
+ CONFIG_PROVE_LOCKING: check that accesses to RCU-protected data
structures are carried out under the proper RCU
read-side critical section, while holding the right
combination of locks, or whatever other conditions