[Cluster-devel] [PATCH 11/30] iomap: add the new iomap_iter model

[Dave Chinner]

On Mon, Aug 09, 2021 at 08:12:25AM +0200, Christoph Hellwig wrote:
> The iomap_iter struct provides a convenient way to package up and
> maintain all the arguments to the various mapping and operation
> functions.  It is operated on using the iomap_iter() function that
> is called in loop until the whole range has been processed.  Compared
> to the existing iomap_apply() function this avoid an indirect call
> for each iteration.
> 
> For now iomap_iter() calls back into the existing ->iomap_begin and
> ->iomap_end methods, but in the future this could be further optimized
> to avoid indirect calls entirely.
> 
> Based on an earlier patch from Matthew Wilcox <willy at infradead.org>.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> ---
>  fs/iomap/Makefile     |  1 +
>  fs/iomap/core.c       | 79 +++++++++++++++++++++++++++++++++++++++++++
>  fs/iomap/trace.h      | 37 +++++++++++++++++++-
>  include/linux/iomap.h | 56 ++++++++++++++++++++++++++++++
>  4 files changed, 172 insertions(+), 1 deletion(-)
>  create mode 100644 fs/iomap/core.c
> 
> diff --git a/fs/iomap/Makefile b/fs/iomap/Makefile
> index eef2722d93a183..6b56b10ded347a 100644
> --- a/fs/iomap/Makefile
> +++ b/fs/iomap/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_FS_IOMAP)		+= iomap.o
>  
>  iomap-y				+= trace.o \
>  				   apply.o \
> +				   core.o \

This creates a discontinuity in the iomap git history. Can you add
these new functions to iomap/apply.c, then when the old apply code
is removed later in the series rename the file to core.c? At least
that way 'git log --follow fs/iomap/core.c' will walk back into the
current history of fs/iomap/apply.c and the older pre-disaggregation
fs/iomap.c without having to take the tree back in time to find
those files...

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com