Re: [PATCH 46/48] truncate,shmem: Handle truncates that split large folios

[Matthew Wilcox <willy@xxxxxxxxxxxxx>]

On Wed, Dec 08, 2021 at 04:22:54AM +0000, Matthew Wilcox (Oracle) wrote:
> @@ -917,13 +904,13 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
>  	struct shmem_inode_info *info = SHMEM_I(inode);
>  	pgoff_t start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
>  	pgoff_t end = (lend + 1) >> PAGE_SHIFT;
> -	unsigned int partial_start = lstart & (PAGE_SIZE - 1);
> -	unsigned int partial_end = (lend + 1) & (PAGE_SIZE - 1);
>  	struct folio_batch fbatch;
>  	pgoff_t indices[PAGEVEC_SIZE];
> +	struct folio *folio;

This turns a couple of other definitions of struct folio in this
function into shadowed definitions.  We don't have -Wshadow turned
on, so I didn't notice until doing more patch review this morning.
I'm going to fold in this patch:

+++ b/mm/shmem.c
@@ -919,7 +919,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
        while (index < end && find_lock_entries(mapping, index, end - 1,
                        &fbatch, indices)) {
                for (i = 0; i < folio_batch_count(&fbatch); i++) {
-                       struct folio *folio = fbatch.folios[i];
+                       folio = fbatch.folios[i];

                        index = indices[i];

@@ -985,7 +985,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
                        continue;
                }
                for (i = 0; i < folio_batch_count(&fbatch); i++) {
-                       struct folio *folio = fbatch.folios[i];
+                       folio = fbatch.folios[i];

                        index = indices[i];
                        if (xa_is_value(folio)) {