X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=Documentation%2Flocal_ops.txt;h=f4f8b1c6c8ba45ba6ec351aa92c40e798024983c;hb=984f2f377fdfd098f5ae58d09ee04d5e29e6112b;hp=1a45f11e645e978f445ba7396f0c5411a1695e06;hpb=d12dbbfe948c89156ad1b0fe7c808ba4d6f00bc2;p=linux-2.6-omap-h63xx.git

diff --git a/Documentation/local_ops.txt b/Documentation/local_ops.txt
index 1a45f11e645..f4f8b1c6c8b 100644
--- a/Documentation/local_ops.txt
+++ b/Documentation/local_ops.txt
@@ -36,7 +36,7 @@ It can be done by slightly modifying the standard atomic operations : only
 their UP variant must be kept. It typically means removing LOCK prefix (on
 i386 and x86_64) and any SMP sychronization barrier. If the architecture does
 not have a different behavior between SMP and UP, including asm-generic/local.h
-in your archtecture's local.h is sufficient.
+in your architecture's local.h is sufficient.
 
 The local_t type is defined as an opaque signed long by embedding an
 atomic_long_t inside a structure. This is made so a cast from this type to a
@@ -45,29 +45,6 @@ long fails. The definition looks like :
 typedef struct { atomic_long_t a; } local_t;
 
 
-* Rules to follow when using local atomic operations
-
-- Variables touched by local ops must be per cpu variables.
-- _Only_ the CPU owner of these variables must write to them.
-- This CPU can use local ops from any context (process, irq, softirq, nmi, ...)
-  to update its local_t variables.
-- Preemption (or interrupts) must be disabled when using local ops in
-  process context to   make sure the process won't be migrated to a
-  different CPU between getting the per-cpu variable and doing the
-  actual local op.
-- When using local ops in interrupt context, no special care must be
-  taken on a mainline kernel, since they will run on the local CPU with
-  preemption already disabled. I suggest, however, to explicitly
-  disable preemption anyway to make sure it will still work correctly on
-  -rt kernels.
-- Reading the local cpu variable will provide the current copy of the
-  variable.
-- Reads of these variables can be done from any CPU, because updates to
-  "long", aligned, variables are always atomic. Since no memory
-  synchronization is done by the writer CPU, an outdated copy of the
-  variable can be read when reading some _other_ cpu's variables.
-
-
 * Rules to follow when using local atomic operations
 
 - Variables touched by local ops must be per cpu variables.