mm: stop passing a writeback_control structure to shmem_writeout

shmem_writeout only needs the swap_iocb cookie and the split folio
list.  Pass those explicitly and remove the now unused list member
from struct writeback_control.

Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
index 19a3eb82dc6a6aaa88a2a1846be47889dd4233ba..24d8daa4fdb35b7869b8c24b345c8d6cb7a1fd87 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
@@ -317,7 +317,7 @@ void __shmem_writeback(size_t size, struct address_space *mapping)
                if (folio_mapped(folio))
                        folio_redirty_for_writepage(&wbc, folio);
                else
-                       error = shmem_writeout(folio, &wbc);
+                       error = shmem_writeout(folio, NULL, NULL);
        }
 }
 

diff --git a/drivers/gpu/drm/ttm/ttm_backup.c b/drivers/gpu/drm/ttm/ttm_backup.c
index ffaab68bd5dd2ff337b1d99e9ce5cd69dcfe088b..6f2e58be4f3e340c2987c2b7539bed49d04c58a2 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_backup.c
+++ b/drivers/gpu/drm/ttm/ttm_backup.c
@@ -112,15 +112,8 @@ ttm_backup_backup_page(struct file *backup, struct page *page,
 
        if (writeback && !folio_mapped(to_folio) &&
            folio_clear_dirty_for_io(to_folio)) {
-               struct writeback_control wbc = {
-                       .sync_mode = WB_SYNC_NONE,
-                       .nr_to_write = SWAP_CLUSTER_MAX,
-                       .range_start = 0,
-                       .range_end = LLONG_MAX,
-                       .for_reclaim = 1,
-               };
                folio_set_reclaim(to_folio);
-               ret = shmem_writeout(to_folio, &wbc);
+               ret = shmem_writeout(to_folio, NULL, NULL);
                if (!folio_test_writeback(to_folio))
                        folio_clear_reclaim(to_folio);
                /*

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 5f03a39a26f716b81b17ac716c6d5e16be98bb94..6d0f9c599ff7ecdd3036279841255f49e6b86c82 100644 (file)
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -11,6 +11,8 @@
 #include <linux/fs_parser.h>
 #include <linux/userfaultfd_k.h>
 
+struct swap_iocb;
+
 /* inode in-kernel data */
 
 #ifdef CONFIG_TMPFS_QUOTA
@@ -107,7 +109,8 @@ static inline bool shmem_mapping(struct address_space *mapping)
 void shmem_unlock_mapping(struct address_space *mapping);
 struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
                                        pgoff_t index, gfp_t gfp_mask);
-int shmem_writeout(struct folio *folio, struct writeback_control *wbc);
+int shmem_writeout(struct folio *folio, struct swap_iocb **plug,
+               struct list_head *folio_list);
 void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
 int shmem_unuse(unsigned int type);
 

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index eda4b62511f70fc3c736a88c7456690d70cdd21b..82f217970092aa0a35c83e9d98546dd3fab3a9a6 100644 (file)
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -79,9 +79,6 @@ struct writeback_control {
         */
        struct swap_iocb **swap_plug;
 
-       /* Target list for splitting a large folio */
-       struct list_head *list;
-
        /* internal fields used by the ->writepages implementation: */
        struct folio_batch fbatch;
        pgoff_t index;

diff --git a/mm/shmem.c b/mm/shmem.c
index 858cee02ca49ab502ab4504def2c4f26e8b6fd96..941b9b29e78a3d610544859793d5365f0b52750b 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1540,10 +1540,13 @@ int shmem_unuse(unsigned int type)
  * shmem_writeout - Write the folio to swap
  * @folio: The folio to write
  * @wbc: How writeback is to be done
+ * @plug: swap plug
+ * @folio_list: list to put back folios on split
  *
  * Move the folio from the page cache to the swap cache.
  */
-int shmem_writeout(struct folio *folio, struct writeback_control *wbc)
+int shmem_writeout(struct folio *folio, struct swap_iocb **plug,
+               struct list_head *folio_list)
 {
        struct address_space *mapping = folio->mapping;
        struct inode *inode = mapping->host;
@@ -1553,9 +1556,6 @@ int shmem_writeout(struct folio *folio, struct writeback_control *wbc)
        int nr_pages;
        bool split = false;
 
-       if (WARN_ON_ONCE(!wbc->for_reclaim))
-               goto redirty;
-
        if ((info->flags & VM_LOCKED) || sbinfo->noswap)
                goto redirty;
 
@@ -1582,7 +1582,7 @@ int shmem_writeout(struct folio *folio, struct writeback_control *wbc)
 try_split:
                /* Ensure the subpages are still dirty */
                folio_test_set_dirty(folio);
-               if (split_folio_to_list(folio, wbc->list))
+               if (split_folio_to_list(folio, folio_list))
                        goto redirty;
                folio_clear_dirty(folio);
        }
@@ -1635,13 +1635,21 @@ try_split:
                list_add(&info->swaplist, &shmem_swaplist);
 
        if (!folio_alloc_swap(folio, __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN)) {
+               struct writeback_control wbc = {
+                       .sync_mode      = WB_SYNC_NONE,
+                       .nr_to_write    = SWAP_CLUSTER_MAX,
+                       .range_start    = 0,
+                       .range_end      = LLONG_MAX,
+                       .for_reclaim    = 1,
+                       .swap_plug      = plug,
+               };
                shmem_recalc_inode(inode, 0, nr_pages);
                swap_shmem_alloc(folio->swap, nr_pages);
                shmem_delete_from_page_cache(folio, swp_to_radix_entry(folio->swap));
 
                mutex_unlock(&shmem_swaplist_mutex);
                BUG_ON(folio_mapped(folio));
-               return swap_writeout(folio, wbc);
+               return swap_writeout(folio, &wbc);
        }
 
        list_del_init(&info->swaplist);
@@ -1650,10 +1658,7 @@ try_split:
                goto try_split;
 redirty:
        folio_mark_dirty(folio);
-       if (wbc->for_reclaim)
-               return AOP_WRITEPAGE_ACTIVATE;  /* Return with folio locked */
-       folio_unlock(folio);
-       return 0;
+       return AOP_WRITEPAGE_ACTIVATE;  /* Return with folio locked */
 }
 EXPORT_SYMBOL_GPL(shmem_writeout);
 

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 52e6eee4d8966cdf7844ed37fa0d2263977f59be..2cf954006d6db0e10312a8cf4cde1488b259267d 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -669,15 +669,13 @@ static pageout_t writeout(struct folio *folio, struct address_space *mapping,
 
        /*
         * The large shmem folio can be split if CONFIG_THP_SWAP is not enabled
-        * or we failed to allocate contiguous swap entries.
+        * or we failed to allocate contiguous swap entries, in which case
+        * the split out folios get added back to folio_list.
         */
-       if (shmem_mapping(mapping)) {
-               if (folio_test_large(folio))
-                       wbc.list = folio_list;
-               res = shmem_writeout(folio, &wbc);
-       } else {
+       if (shmem_mapping(mapping))
+               res = shmem_writeout(folio, plug, folio_list);
+       else
                res = swap_writeout(folio, &wbc);
-       }
 
        if (res < 0)
                handle_write_error(mapping, folio, res);