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authorVishal Moola (Oracle) <vishal.moola@gmail.com>2022-10-17 09:17:59 -0700
committerAndrew Morton <akpm@linux-foundation.org>2022-11-08 17:37:12 -0800
commit3392ca121872dd8c33015c7703d4981c78819be3 (patch)
tree6d7b09f70f2271aae7c83311c8442e189fa5fff3
parentd8e454eb44473b2270e2675fb44a9d79dee36097 (diff)
filemap: find_lock_entries() now updates start offset
Patch series "Rework find_get_entries() and find_lock_entries()", v3. Originally the callers of find_get_entries() and find_lock_entries() were keeping track of the start index themselves as they traverse the search range. This resulted in hacky code such as in shmem_undo_range(): index = folio->index + folio_nr_pages(folio) - 1; where the - 1 is only present to stay in the right spot after incrementing index later. This sort of calculation was also being done on every folio despite not even using index later within that function. These patches change find_get_entries() and find_lock_entries() to calculate the new index instead of leaving it to the callers so we can avoid all these complications. This patch (of 2): Initially, find_lock_entries() was being passed in the start offset as a value. That left the calculation of the offset to the callers. This led to complexity in the callers trying to keep track of the index. Now find_lock_entries() takes in a pointer to the start offset and updates the value to be directly after the last entry found. If no entry is found, the offset is not changed. This gets rid of multiple hacky calculations that kept track of the start offset. Link: https://lkml.kernel.org/r/20221017161800.2003-1-vishal.moola@gmail.com Link: https://lkml.kernel.org/r/20221017161800.2003-2-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--mm/filemap.c15
-rw-r--r--mm/internal.h2
-rw-r--r--mm/shmem.c8
-rw-r--r--mm/truncate.c11
4 files changed, 18 insertions, 18 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 08341616ae7a..3a73b7b8c2a4 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2085,16 +2085,16 @@ unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
*
* Return: The number of entries which were found.
*/
-unsigned find_lock_entries(struct address_space *mapping, pgoff_t start,
+unsigned find_lock_entries(struct address_space *mapping, pgoff_t *start,
pgoff_t end, struct folio_batch *fbatch, pgoff_t *indices)
{
- XA_STATE(xas, &mapping->i_pages, start);
+ XA_STATE(xas, &mapping->i_pages, *start);
struct folio *folio;
rcu_read_lock();
while ((folio = find_get_entry(&xas, end, XA_PRESENT))) {
if (!xa_is_value(folio)) {
- if (folio->index < start)
+ if (folio->index < *start)
goto put;
if (folio->index + folio_nr_pages(folio) - 1 > end)
goto put;
@@ -2117,6 +2117,15 @@ put:
}
rcu_read_unlock();
+ if (folio_batch_count(fbatch)) {
+ unsigned long nr = 1;
+ int idx = folio_batch_count(fbatch) - 1;
+
+ folio = fbatch->folios[idx];
+ if (!xa_is_value(folio) && !folio_test_hugetlb(folio))
+ nr = folio_nr_pages(folio);
+ *start = indices[idx] + nr;
+ }
return folio_batch_count(fbatch);
}
diff --git a/mm/internal.h b/mm/internal.h
index 6b7ef495b56d..c504ac7267e0 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -106,7 +106,7 @@ static inline void force_page_cache_readahead(struct address_space *mapping,
force_page_cache_ra(&ractl, nr_to_read);
}
-unsigned find_lock_entries(struct address_space *mapping, pgoff_t start,
+unsigned find_lock_entries(struct address_space *mapping, pgoff_t *start,
pgoff_t end, struct folio_batch *fbatch, pgoff_t *indices);
unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
pgoff_t end, struct folio_batch *fbatch, pgoff_t *indices);
diff --git a/mm/shmem.c b/mm/shmem.c
index c1d8b8a1aa3b..6b560c3915af 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -922,21 +922,18 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
folio_batch_init(&fbatch);
index = start;
- while (index < end && find_lock_entries(mapping, index, end - 1,
+ while (index < end && find_lock_entries(mapping, &index, end - 1,
&fbatch, indices)) {
for (i = 0; i < folio_batch_count(&fbatch); i++) {
folio = fbatch.folios[i];
- index = indices[i];
-
if (xa_is_value(folio)) {
if (unfalloc)
continue;
nr_swaps_freed += !shmem_free_swap(mapping,
- index, folio);
+ indices[i], folio);
continue;
}
- index += folio_nr_pages(folio) - 1;
if (!unfalloc || !folio_test_uptodate(folio))
truncate_inode_folio(mapping, folio);
@@ -945,7 +942,6 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
folio_batch_remove_exceptionals(&fbatch);
folio_batch_release(&fbatch);
cond_resched();
- index++;
}
same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT);
diff --git a/mm/truncate.c b/mm/truncate.c
index c0be77e5c008..b6065a494c71 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -361,9 +361,8 @@ void truncate_inode_pages_range(struct address_space *mapping,
folio_batch_init(&fbatch);
index = start;
- while (index < end && find_lock_entries(mapping, index, end - 1,
+ while (index < end && find_lock_entries(mapping, &index, end - 1,
&fbatch, indices)) {
- index = indices[folio_batch_count(&fbatch) - 1] + 1;
truncate_folio_batch_exceptionals(mapping, &fbatch, indices);
for (i = 0; i < folio_batch_count(&fbatch); i++)
truncate_cleanup_folio(fbatch.folios[i]);
@@ -510,20 +509,17 @@ unsigned long invalidate_mapping_pagevec(struct address_space *mapping,
int i;
folio_batch_init(&fbatch);
- while (find_lock_entries(mapping, index, end, &fbatch, indices)) {
+ while (find_lock_entries(mapping, &index, end, &fbatch, indices)) {
for (i = 0; i < folio_batch_count(&fbatch); i++) {
struct folio *folio = fbatch.folios[i];
/* We rely upon deletion not changing folio->index */
- index = indices[i];
if (xa_is_value(folio)) {
count += invalidate_exceptional_entry(mapping,
- index,
- folio);
+ indices[i], folio);
continue;
}
- index += folio_nr_pages(folio) - 1;
ret = mapping_evict_folio(mapping, folio);
folio_unlock(folio);
@@ -542,7 +538,6 @@ unsigned long invalidate_mapping_pagevec(struct address_space *mapping,
folio_batch_remove_exceptionals(&fbatch);
folio_batch_release(&fbatch);
cond_resched();
- index++;
}
return count;
}