writeback_iter() returns a locked folio. The mapped-folio path redirties
the folio without unlocking it, so shrinking can leave the folio locked
indefinitely.
shmem_write_folio() can also return AOP_WRITEPAGE_ACTIVATE with the folio
locked. Passing that positive control value back to writeback_iter()
triggers its warning, stops asynchronous writeback, and leaves the folio
locked. This can occur when zswap rejects a folio while memcg zswap
writeback is disabled.
Unlock folios on both paths and consume AOP_WRITEPAGE_ACTIVATE so the
best-effort writeback scan can continue.
Fixes: 776a853a43c9 ("i915: Use writeback_iter()")
Cc: [email protected]
Signed-off-by: Matthias Goergens <[email protected]>
---
drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
index ef9440166295..e7b18f7f9644 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
@@ -322,10 +322,16 @@ void __shmem_writeback(size_t size, struct address_space
*mapping)
* as normal.
*/
while ((folio = writeback_iter(mapping, &wbc, folio, &error))) {
- if (folio_mapped(folio))
+ if (folio_mapped(folio)) {
folio_redirty_for_writepage(&wbc, folio);
- else
+ folio_unlock(folio);
+ } else {
error = shmem_write_folio(folio);
+ if (error == AOP_WRITEPAGE_ACTIVATE) {
+ folio_unlock(folio);
+ error = 0;
+ }
+ }
}
}
base-commit: cbd3dafc2003db679ccd2f6c6a2551db79657049
--
2.55.0
