Messages in this thread | | | Date | Fri, 06 Mar 2009 17:01:48 +0800 | From | Li Zefan <> | Subject | Re: [RFC][PATCH] kmemdup_from_user(): introduce |
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Andrew Morton wrote: > On Fri, 06 Mar 2009 16:27:53 +0800 Li Zefan <lizf@cn.fujitsu.com> wrote: > >>> Let's not add wrapper for every two lines that happen to be used >>> together. >>> >> Why not if we have good reasons? And I don't think we can call this >> "happen to" if there are 250+ of them? > > The change is a good one. If a reviewer (me) sees it then you know the > code's all right and the review effort becomes less - all you need to check > is that the call site is using IS_ERR/PTR_ERR and isn't testing for > NULL. Less code, less chance for bugs. > > Plus it makes kernel text smaller. > > Yes, the name is a bit cumbersome. >
How about memdup_user()? like kstrndup() vs strndup_user().
Here is the statistics when using 5 kmemdup_from_user() in btrfs:
$ diffstat ioctl.c | 49 ++++++++++++------------------------------------- super.c | 13 ++++--------- 2 files changed, 16 insertions(+), 46 deletions(-)
the kernel size on i386:
text data bss dec hex filename 288339 1924 508 290771 46fd3 fs/btrfs/btrfs.o.orig text data bss dec hex filename 288255 1924 508 290687 46f7f fs/btrfs/btrfs.o
so saves 84 bytes.
the kernel size on IA64:
text data bss dec hex filename 898752 3736 109 902597 dc5c5 fs/btrfs/btrfs.o.orig text data bss dec hex filename 898176 3712 109 901997 dc36d fs/btrfs/btrfs.o
so saves 576 bytes.
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