pipe: simplify round_pipe_size()

round_pipe_size() calculates the number of pages the requested size
corresponds to, then rounds the page count up to the next power of 2.

However, it also rounds everything < PAGE_SIZE up to PAGE_SIZE.
Therefore, there's no need to actually translate the size into a page
count; we just need to round the size up to the next power of 2.

We do need to verify the size isn't greater than (1 << 31), since on
32-bit systems roundup_pow_of_two() would be undefined in that case.  But
that can just be combined with the UINT_MAX check which we need anyway
now.

Finally, update pipe_set_size() to not redundantly check the return value
of round_pipe_size() for the "invalid size" case twice.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Eric Biggers <[email protected]>
Acked-by: Kees Cook <[email protected]>
Acked-by: Joe Lawrence <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: "Luis R . Rodriguez" <[email protected]>
Cc: Michael Kerrisk <[email protected]>
Cc: Mikulas Patocka <[email protected]>
Cc: Willy Tarreau <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions