From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1425199AbdEYWJm (ORCPT ); Thu, 25 May 2017 18:09:42 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:48838 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S943083AbdEYWAQ (ORCPT ); Thu, 25 May 2017 18:00:16 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, "Paul E. McKenney" , Fengguang Wu Subject: [PATCH tip/core/rcu 80/88] rcu: Remove SPARSE_RCU_POINTER Kconfig option Date: Thu, 25 May 2017 14:59:53 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20170525215934.GA11578@linux.vnet.ibm.com> References: <20170525215934.GA11578@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17052522-0024-0000-0000-0000027B8C90 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007117; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000212; SDB=6.00865574; UDB=6.00429833; IPR=6.00645396; BA=6.00005375; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015583; XFM=3.00000015; UTC=2017-05-25 22:00:13 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17052522-0025-0000-0000-00004422F45E Message-Id: <1495749601-21574-80-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-05-25_17:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1705250401 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Signed-off-by: Paul E. McKenney Cc: Fengguang Wu --- Documentation/RCU/Design/Requirements/Requirements.html | 9 +++------ Documentation/RCU/checklist.txt | 8 ++++---- Documentation/dev-tools/sparse.rst | 6 ------ include/linux/compiler.h | 4 ---- lib/Kconfig.debug | 15 --------------- lib/Makefile | 3 --- .../testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt | 4 ---- 7 files changed, 7 insertions(+), 42 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 rcu_access_pointer() on line 6 is similar to For remove_gp_synchronous(), as long as all modifications to gp are carried out while holding gp_lock, the above optimizations are harmless. - However, - with CONFIG_SPARSE_RCU_POINTER=y, - sparse will complain if you + However, sparse will complain if you define gp with __rcu and then access it without using either rcu_access_pointer() or rcu_dereference(). @@ -1978,9 +1976,8 @@ guard against mishaps and misuse: and rcu_dereference(), perhaps (incorrectly) substituting a simple assignment. To catch this sort of error, a given RCU-protected pointer may be - tagged with __rcu, after which running sparse - with CONFIG_SPARSE_RCU_POINTER=y will complain - about simple-assignment accesses to that pointer. + tagged with __rcu, 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 patch series. 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 diff --git a/Documentation/dev-tools/sparse.rst b/Documentation/dev-tools/sparse.rst index ffdcc97f6f5a..78aa00a604a0 100644 --- a/Documentation/dev-tools/sparse.rst +++ b/Documentation/dev-tools/sparse.rst @@ -103,9 +103,3 @@ have already built it. The optional make variable CF can be used to pass arguments to sparse. The build system passes -Wbitwise to sparse automatically. - -Checking RCU annotations -~~~~~~~~~~~~~~~~~~~~~~~~ - -RCU annotations are not checked by default. To enable RCU annotation -checks, include -DCONFIG_SPARSE_RCU_POINTER in your CF flags. diff --git a/include/linux/compiler.h b/include/linux/compiler.h index f8110051188f..707242fdbb89 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -17,11 +17,7 @@ # define __release(x) __context__(x,-1) # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0) # define __percpu __attribute__((noderef, address_space(3))) -#ifdef CONFIG_SPARSE_RCU_POINTER # define __rcu __attribute__((noderef, address_space(4))) -#else /* CONFIG_SPARSE_RCU_POINTER */ -# define __rcu -#endif /* CONFIG_SPARSE_RCU_POINTER */ # define __private __attribute__((noderef)) extern void __chk_user_ptr(const volatile void __user *); extern void __chk_io_ptr(const volatile void __iomem *); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 762deab304fe..498d5dd63bf4 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1306,21 +1306,6 @@ menu "RCU Debugging" config PROVE_RCU def_bool PROVE_LOCKING -config SPARSE_RCU_POINTER - bool "RCU debugging: sparse-based checks for pointer usage" - default n - help - This feature enables the __rcu sparse annotation for - RCU-protected pointers. This annotation will cause sparse - to flag any non-RCU used of annotated pointers. This can be - helpful when debugging RCU usage. Please note that this feature - is not intended to enforce code cleanliness; it is instead merely - a debugging aid. - - Say Y to make sparse flag questionable use of RCU-protected pointers - - Say N if you are unsure. - config TORTURE_TEST tristate default n diff --git a/lib/Makefile b/lib/Makefile index 0166fbc0fa81..07fbe6a75692 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -25,9 +25,6 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ earlycpio.o seq_buf.o siphash.o \ nmi_backtrace.o nodemask.o win_minmax.o -CFLAGS_radix-tree.o += -DCONFIG_SPARSE_RCU_POINTER -CFLAGS_idr.o += -DCONFIG_SPARSE_RCU_POINTER - lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o lib-$(CONFIG_DMA_NOOP_OPS) += dma-noop.o diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt index b778a28f1386..c5c29fb7438c 100644 --- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt +++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt @@ -74,10 +74,6 @@ CONFIG_TINY_RCU These are controlled by CONFIG_PREEMPT and/or CONFIG_SMP. -CONFIG_SPARSE_RCU_POINTER - - Makes sense only for sparse runs, not for kernel builds. - CONFIG_SRCU CONFIG_TASKS_RCU -- 2.5.2