filemap: Correct the conditions for marking a folio as accessed

mainline inclusion
from mainline-5.19-rc4
commit 5ccc944d
category: bugfix
bugzilla: 186896, https://gitee.com/src-openeuler/kernel/issues/I5GZC8
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5ccc944dce3df5fd2fd683a7df4fd49d1068eba2



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We had an off-by-one error which meant that we never marked the first page
in a read as accessed.  This was visible as a slowdown when re-reading
a file as pages were being evicted from cache too soon.  In reviewing
this code, we noticed a second bug where a multi-page folio would be
marked as accessed multiple times when doing reads that were less than
the size of the folio.

Abstract the comparison of whether two file positions are in the same
folio into a new function, fixing both of these bugs.

Reported-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Conflict: folios is not supported yet
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>