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author | Al Viro <viro@zeniv.linux.org.uk> | 2016-09-18 03:44:45 +0300 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2016-10-04 03:40:55 +0300 |
commit | 8924feff66f35fe22ce77aafe3f21eb8e5cff881 (patch) | |
tree | 77d74a5edba4d1a30f484e0cffdecfcfcc113d79 /include/linux/splice.h | |
parent | db85a9eb2e364e24e71f94798e85dbaa8111bb4d (diff) | |
download | linux-8924feff66f35fe22ce77aafe3f21eb8e5cff881.tar.xz |
splice: lift pipe_lock out of splice_to_pipe()
* splice_to_pipe() stops at pipe overflow and does *not* take pipe_lock
* ->splice_read() instances do the same
* vmsplice_to_pipe() and do_splice() (ultimate callers of splice_to_pipe())
arrange for waiting, looping, etc. themselves.
That should make pipe_lock the outermost one.
Unfortunately, existing rules for the amount passed by vmsplice_to_pipe()
and do_splice() are quite ugly _and_ userland code can be easily broken
by changing those. It's not even "no more than the maximal capacity of
this pipe" - it's "once we'd fed pipe->nr_buffers pages into the pipe,
leave instead of waiting".
Considering how poorly these rules are documented, let's try "wait for some
space to appear, unless given SPLICE_F_NONBLOCK, then push into pipe
and if we run into overflow, we are done".
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/splice.h')
0 files changed, 0 insertions, 0 deletions