From c4f9a1ba747dbf3b090948b528e0b408d4117137 Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Tue, 6 May 2025 09:41:16 -0400 Subject: [PATCH] iomap: helper to trim pos/bytes to within folio Several buffered write based iteration callbacks duplicate logic to trim the current pos and length to within the current folio. Factor this into a helper to make it easier to relocate closer to folio lookup. Signed-off-by: Brian Foster Link: https://lore.kernel.org/20250506134118.911396-5-bfoster@redhat.com Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/iomap/buffered-io.c | 35 ++++++++++++++++++++--------------- 1 file changed, 20 insertions(+), 15 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 4a1cc59033d52..01b9e0cbabf20 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -766,6 +766,22 @@ static void __iomap_put_folio(struct iomap_iter *iter, size_t ret, } } +/* trim pos and bytes to within a given folio */ +static loff_t iomap_trim_folio_range(struct iomap_iter *iter, + struct folio *folio, size_t *offset, u64 *bytes) +{ + loff_t pos = iter->pos; + size_t fsize = folio_size(folio); + + WARN_ON_ONCE(pos < folio_pos(folio)); + WARN_ON_ONCE(pos >= folio_pos(folio) + fsize); + + *offset = offset_in_folio(folio, pos); + *bytes = min(*bytes, fsize - *offset); + + return pos; +} + static int iomap_write_begin_inline(const struct iomap_iter *iter, struct folio *folio) { @@ -920,7 +936,7 @@ static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i) struct folio *folio; loff_t old_size; size_t offset; /* Offset into folio */ - size_t bytes; /* Bytes to write to folio */ + u64 bytes; /* Bytes to write to folio */ size_t copied; /* Bytes copied from user */ u64 written; /* Bytes have been written */ loff_t pos; @@ -959,11 +975,8 @@ retry: } if (iter->iomap.flags & IOMAP_F_STALE) break; - pos = iter->pos; - offset = offset_in_folio(folio, pos); - if (bytes > folio_size(folio) - offset) - bytes = folio_size(folio) - offset; + pos = iomap_trim_folio_range(iter, folio, &offset, &bytes); if (mapping_writably_mapped(mapping)) flush_dcache_folio(folio); @@ -1280,7 +1293,6 @@ static int iomap_unshare_iter(struct iomap_iter *iter) do { struct folio *folio; size_t offset; - loff_t pos; bool ret; bytes = min_t(u64, SIZE_MAX, bytes); @@ -1289,11 +1301,8 @@ static int iomap_unshare_iter(struct iomap_iter *iter) return status; if (iomap->flags & IOMAP_F_STALE) break; - pos = iter->pos; - offset = offset_in_folio(folio, pos); - if (bytes > folio_size(folio) - offset) - bytes = folio_size(folio) - offset; + iomap_trim_folio_range(iter, folio, &offset, &bytes); ret = iomap_write_end(iter, bytes, bytes, folio); __iomap_put_folio(iter, bytes, folio); @@ -1356,7 +1365,6 @@ static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) do { struct folio *folio; size_t offset; - loff_t pos; bool ret; bytes = min_t(u64, SIZE_MAX, bytes); @@ -1365,14 +1373,11 @@ static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) return status; if (iter->iomap.flags & IOMAP_F_STALE) break; - pos = iter->pos; /* warn about zeroing folios beyond eof that won't write back */ WARN_ON_ONCE(folio_pos(folio) > iter->inode->i_size); - offset = offset_in_folio(folio, pos); - if (bytes > folio_size(folio) - offset) - bytes = folio_size(folio) - offset; + iomap_trim_folio_range(iter, folio, &offset, &bytes); folio_zero_range(folio, offset, bytes); folio_mark_accessed(folio); -- 2.47.2