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shmem: convert shmem_write_end() to use a folio 

Use a folio internally to shmem_write_end() which saves a number of calls
to compound_head() and lets us get rid of the custom code to zero out the
rest of a THP and supports folios of arbitrary size.

Link: https://lkml.kernel.org/r/20230112131031.1209553-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2023-01-12 13:10:31 +00:00 committed by Andrew Morton
parent a6fddef49e
commit 69bbb87b3f
1 changed files with 10 additions and 20 deletions
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30
mm/shmem.c
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@ -2578,33 +2578,23 @@ shmem_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct folio *folio = page_folio(page);
struct inode *inode = mapping->host;
if (pos + copied > inode->i_size)
i_size_write(inode, pos + copied);
if (!PageUptodate(page)) {
struct page *head = compound_head(page);
if (PageTransCompound(page)) {
int i;
for (i = 0; i < HPAGE_PMD_NR; i++) {
if (head + i == page)
continue;
clear_highpage(head + i);
flush_dcache_page(head + i);
}
if (!folio_test_uptodate(folio)) {
if (copied < folio_size(folio)) {
size_t from = offset_in_folio(folio, pos);
folio_zero_segments(folio, 0, from,
from + copied, folio_size(folio));
}
if (copied < PAGE_SIZE) {
unsigned from = pos & (PAGE_SIZE - 1);
zero_user_segments(page, 0, from,
from + copied, PAGE_SIZE);
}
SetPageUptodate(head);
folio_mark_uptodate(folio);
}
set_page_dirty(page);
unlock_page(page);
put_page(page);
folio_mark_dirty(folio);
folio_unlock(folio);
folio_put(folio);
return copied;
}