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>
This commit is contained in:
Steffen Klassert 2010-07-07 15:34:03 +02:00 committed by Herbert Xu
parent 5f1a8c1bc7
commit 2197f9a16d

View file

@ -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