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Wong via Linux-f2fs-devel" Reply-To: "Darrick J. Wong" Cc: fsverity@lists.linux.dev, ebiggers@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, hch@lst.de, linux-btrfs@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Mon, Aug 03, 2026 at 10:07:55PM +0200, Andrey Albershteyn wrote: > The current version calls flush_dcache_folio(), in memcpy_to_folio(), to > flush whole folio on every digest (which is 128 for 4k) on the HIGHMEM > systems. Open code folio mapping and flushing to copy all digests at > once. Do we really have to care about HIGHMEM performance? I thought that was going soon anyway[1]. The code change *looks* reasonable but ugh it adds more complexity and how many 32-bit phones and servers are there? (For Andrey: Why is this bolted onto an XFS patchset? Nobody should run XFS on 32-bit at all these days.) --D [1] https://lwn.net/Articles/1051010/ > Reported-by: Eric Biggers > Link: https://lore.kernel.org/linux-fsdevel/20260401222717.GH2466@quark/ > Signed-off-by: Andrey Albershteyn > --- > fs/verity/pagecache.c | 28 ++++++++++++++++++++++++++-- > 1 file changed, 26 insertions(+), 2 deletions(-) > > diff --git a/fs/verity/pagecache.c b/fs/verity/pagecache.c > index 9d82e6b74ba1..911207dc0ef7 100644 > --- a/fs/verity/pagecache.c > +++ b/fs/verity/pagecache.c > @@ -68,14 +68,38 @@ EXPORT_SYMBOL_GPL(generic_readahead_merkle_tree); > void fsverity_fill_zerohash(struct folio *folio, size_t offset, size_t len, > struct fsverity_info *vi) > { > - size_t off = offset; > + size_t off; > > WARN_ON_ONCE(!IS_ALIGNED(offset, vi->tree_params.digest_size)); > WARN_ON_ONCE(!IS_ALIGNED(len, vi->tree_params.digest_size)); > +#ifdef CONFIG_HIGHMEM > + WARN_ON_ONCE(offset + len > folio_size(folio)); > > - for (; off < (offset + len); off += vi->tree_params.digest_size) > + do { > + void *vaddr = kmap_local_folio(folio, offset); > + void *to = vaddr; > + > + off = len; > + > + if (folio_test_partial_kmap(folio) && > + off > PAGE_SIZE - offset_in_page(offset)) > + off = PAGE_SIZE - offset_in_page(offset); > + for (; to < (vaddr + off); to += vi->tree_params.digest_size) > + memcpy(to, vi->tree_params.zero_digest, > + vi->tree_params.digest_size); > + kunmap_local(vaddr); > + > + offset += off; > + len -= off; > + } while (len > 0); > + > + flush_dcache_folio(folio); > +#else > + for (off = offset; off < (offset + len); > + off += vi->tree_params.digest_size) > memcpy_to_folio(folio, off, vi->tree_params.zero_digest, > vi->tree_params.digest_size); > +#endif > } > EXPORT_SYMBOL_GPL(fsverity_fill_zerohash); > > -- > 2.54.0 > > _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel