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authorSteffen Klassert <steffen.klassert@secunet.com>2010-07-07 15:34:03 +0200
committerHerbert Xu <herbert@gondor.apana.org.au>2010-07-14 20:29:30 +0800
commit2197f9a16df9de94655992941d80953ba47042c2 (patch)
tree5b65b1495da03c395253a6661f3a834579aa28a3 /Documentation/padata.txt
parent5f1a8c1bc724498ff32acbd59ed5263275676b9d (diff)
downloadlinux-linaro-android-2197f9a16df9de94655992941d80953ba47042c2.tar.gz
padata: update documentation
This patch updates the padata documentation to the changed API of padata_start/padata_stop and padata_do parallel. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'Documentation/padata.txt')
-rw-r--r--Documentation/padata.txt21
1 files changed, 11 insertions, 10 deletions
diff --git a/Documentation/padata.txt b/Documentation/padata.txt
index 269d7d0d833..93dd4e6db97 100644
--- a/Documentation/padata.txt
+++ b/Documentation/padata.txt
@@ -22,12 +22,15 @@ actually be done; it should be a multithreaded queue, naturally.
There are functions for enabling and disabling the instance:
- void padata_start(struct padata_instance *pinst);
+ int padata_start(struct padata_instance *pinst);
void padata_stop(struct padata_instance *pinst);
-These functions literally do nothing beyond setting or clearing the
-"padata_start() was called" flag; if that flag is not set, other functions
-will refuse to work.
+These functions are setting or clearing the "PADATA_INIT" flag;
+if that flag is not set, other functions will refuse to work.
+padata_start returns zero on success (flag set) or -EINVAL if the
+padata cpumask contains no active cpu (flag not set).
+padata_stop clears the flag and blocks until the padata instance
+is unused.
The list of CPUs to be used can be adjusted with these functions:
@@ -63,12 +66,10 @@ The submission of work is done with:
The pinst and padata structures must be set up as described above; cb_cpu
specifies which CPU will be used for the final callback when the work is
done; it must be in the current instance's CPU mask. The return value from
-padata_do_parallel() is a little strange; zero is an error return
-indicating that the caller forgot the padata_start() formalities. -EBUSY
-means that somebody, somewhere else is messing with the instance's CPU
-mask, while -EINVAL is a complaint about cb_cpu not being in that CPU mask.
-If all goes well, this function will return -EINPROGRESS, indicating that
-the work is in progress.
+padata_do_parallel() is zero on success, indicating that the work is in
+progress. -EBUSY means that somebody, somewhere else is messing with the
+instance's CPU mask, while -EINVAL is a complaint about cb_cpu not being
+in that CPU mask or about a not running instance.
Each task submitted to padata_do_parallel() will, in turn, be passed to
exactly one call to the above-mentioned parallel() function, on one CPU, so