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iov_iter: Convert iter_xarray to use folios

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Take advantage of how kmap_local_folio() works to simplify the loop.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
This commit is contained in:
Matthew Wilcox (Oracle) 2021-11-28 19:18:27 -05:00
parent d9c19d32d8
commit 821979f509
1 changed files with 14 additions and 16 deletions
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30
lib/iov_iter.c
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@ -69,42 +69,40 @@
#define iterate_xarray(i, n, base, len, __off, STEP) { \
__label__ __out; \
size_t __off = 0; \
struct page *head = NULL; \
struct folio *folio; \
loff_t start = i->xarray_start + i->iov_offset; \
unsigned offset = start % PAGE_SIZE; \
pgoff_t index = start / PAGE_SIZE; \
int j; \
\
XA_STATE(xas, i->xarray, index); \
\
len = PAGE_SIZE - offset_in_page(start); \
rcu_read_lock(); \
xas_for_each(&xas, head, ULONG_MAX) { \
xas_for_each(&xas, folio, ULONG_MAX) { \
unsigned left; \
if (xas_retry(&xas, head)) \
size_t offset; \
if (xas_retry(&xas, folio)) \
continue; \
if (WARN_ON(xa_is_value(head))) \
if (WARN_ON(xa_is_value(folio))) \
break; \
if (WARN_ON(PageHuge(head))) \
if (WARN_ON(folio_test_hugetlb(folio))) \
break; \
for (j = (head->index < index) ? index - head->index : 0; \
j < thp_nr_pages(head); j++) { \
void *kaddr = kmap_local_page(head + j); \
base = kaddr + offset; \
len = PAGE_SIZE - offset; \
offset = offset_in_folio(folio, start + __off); \
while (offset < folio_size(folio)) { \
base = kmap_local_folio(folio, offset); \
len = min(n, len); \
left = (STEP); \
kunmap_local(kaddr); \
kunmap_local(base); \
len -= left; \
__off += len; \
n -= len; \
if (left || n == 0) \
goto __out; \
offset = 0; \
offset += len; \
len = PAGE_SIZE; \
} \
} \
__out: \
rcu_read_unlock(); \
i->iov_offset += __off; \
i->iov_offset += __off; \
n = __off; \
}