Messages in this thread Patch in this message | | | From | Al Viro <> | Subject | [RFC PATCH 19/37] [xarray] iov_iter_npages(): just use DIV_ROUND_UP() | Date | Sun, 6 Jun 2021 19:10:33 +0000 |
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Compiler is capable of recognizing division by power of 2 and turning it into shifts.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> --- lib/iov_iter.c | 16 ++-------------- 1 file changed, 2 insertions(+), 14 deletions(-)
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 04c81481d309..6a968d2ff081 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1938,20 +1938,8 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages) return min(npages, maxpages); } if (iov_iter_is_xarray(i)) { - size_t size = i->count; - unsigned offset; - int npages; - - offset = (i->xarray_start + i->iov_offset) & ~PAGE_MASK; - - npages = 1; - if (size > PAGE_SIZE - offset) { - size -= PAGE_SIZE - offset; - npages += size >> PAGE_SHIFT; - size &= ~PAGE_MASK; - if (size) - npages++; - } + unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; + int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); return min(npages, maxpages); } return 0; -- 2.11.0
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