um: series of __get_user() is costly in sigframe handling
authorAl Viro <viro@ftp.linux.org.uk>
Thu, 18 Aug 2011 19:00:49 +0000 (20:00 +0100)
committerRichard Weinberger <richard@nod.at>
Wed, 2 Nov 2011 13:14:42 +0000 (14:14 +0100)
commita955bd611d6426bf7b61cab01f8ddee9cc169736
treef2f42f996bbb757e6f8ebd805fe1e975893dcc32
parent3d72210bdc1ef67b72ffbd3e74873cae7287f2c6
um: series of __get_user() is costly in sigframe handling

It's not x86, where __get_user() is a single dereference; here it's
a single ptrace(2) call in host, which obviously costs a lot more.
IOW, it's cheaper to do copy_{to,from}_user() once than bother with
fields one by one...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
arch/um/sys-i386/signal.c
arch/um/sys-x86_64/signal.c