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Fri, 29 Aug 2025 16:58:26 -0700 (PDT) Received: from localhost ([2a03:2880:ff:51::]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2490373eb17sm35957745ad.54.2025.08.29.16.58.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Aug 2025 16:58:26 -0700 (PDT) From: Joanne Koong To: brauner@kernel.org, miklos@szeredi.hu Cc: hch@infradead.org, djwong@kernel.org, linux-fsdevel@vger.kernel.org, kernel-team@meta.com, linux-xfs@vger.kernel.org, linux-doc@vger.kernel.org Subject: [PATCH v1 07/16] iomap: iterate through entire folio in iomap_readpage_iter() Date: Fri, 29 Aug 2025 16:56:18 -0700 Message-ID: <20250829235627.4053234-8-joannelkoong@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20250829235627.4053234-1-joannelkoong@gmail.com> References: <20250829235627.4053234-1-joannelkoong@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Iterate through the entire folio in iomap_readpage_iter() in one go instead of in pieces. This will be needed for supporting user-provided async read folio callbacks (not yet added). This additionally makes the iomap_readahead_iter() logic simpler to follow. Signed-off-by: Joanne Koong --- fs/iomap/buffered-io.c | 76 ++++++++++++++++++------------------------ 1 file changed, 33 insertions(+), 43 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index f26544fbcb36..75bbef386b62 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -452,6 +452,7 @@ static int iomap_readpage_iter(struct iomap_iter *iter, loff_t length = iomap_length(iter); struct folio *folio = ctx->cur_folio; size_t poff, plen; + loff_t count; int ret; if (iomap->type == IOMAP_INLINE) { @@ -463,26 +464,30 @@ static int iomap_readpage_iter(struct iomap_iter *iter, /* zero post-eof blocks as the page may be mapped */ ifs_alloc(iter->inode, folio, iter->flags); - iomap_adjust_read_range(iter->inode, folio, &pos, length, &poff, &plen); - if (plen == 0) - goto done; - if (iomap_block_needs_zeroing(iter, pos)) { - folio_zero_range(folio, poff, plen); - iomap_set_range_uptodate(folio, poff, plen); - } else { - iomap_read_folio_range_async(iter, ctx, pos, plen); - } + length = min_t(loff_t, length, + folio_size(folio) - offset_in_folio(folio, pos)); + while (length) { + iomap_adjust_read_range(iter->inode, folio, &pos, + length, &poff, &plen); + count = pos - iter->pos + plen; + if (plen == 0) + return iomap_iter_advance(iter, &count); -done: - /* - * Move the caller beyond our range so that it keeps making progress. - * For that, we have to include any leading non-uptodate ranges, but - * we can skip trailing ones as they will be handled in the next - * iteration. - */ - length = pos - iter->pos + plen; - return iomap_iter_advance(iter, &length); + if (iomap_block_needs_zeroing(iter, pos)) { + folio_zero_range(folio, poff, plen); + iomap_set_range_uptodate(folio, poff, plen); + } else { + iomap_read_folio_range_async(iter, ctx, pos, plen); + } + + length -= count; + ret = iomap_iter_advance(iter, &count); + if (ret) + return ret; + pos = iter->pos; + } + return 0; } static void iomap_readfolio_complete(const struct iomap_iter *iter, @@ -494,20 +499,6 @@ static void iomap_readfolio_complete(const struct iomap_iter *iter, folio_unlock(ctx->cur_folio); } -static int iomap_read_folio_iter(struct iomap_iter *iter, - struct iomap_readpage_ctx *ctx) -{ - int ret; - - while (iomap_length(iter)) { - ret = iomap_readpage_iter(iter, ctx); - if (ret) - return ret; - } - - return 0; -} - int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops) { struct iomap_iter iter = { @@ -523,7 +514,7 @@ int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops) trace_iomap_readpage(iter.inode, 1); while ((ret = iomap_iter(&iter, ops)) > 0) - iter.status = iomap_read_folio_iter(&iter, &ctx); + iter.status = iomap_readpage_iter(&iter, &ctx); iomap_readfolio_complete(&iter, &ctx); @@ -537,16 +528,15 @@ static int iomap_readahead_iter(struct iomap_iter *iter, int ret; while (iomap_length(iter)) { - if (ctx->cur_folio && - offset_in_folio(ctx->cur_folio, iter->pos) == 0) { - if (!ctx->folio_unlocked) - folio_unlock(ctx->cur_folio); - ctx->cur_folio = NULL; - } - if (!ctx->cur_folio) { - ctx->cur_folio = readahead_folio(ctx->rac); - ctx->folio_unlocked = false; - } + if (ctx->cur_folio && !ctx->folio_unlocked) + folio_unlock(ctx->cur_folio); + ctx->cur_folio = readahead_folio(ctx->rac); + /* + * We should never in practice hit this case since + * the iter length matches the readahead length. + */ + WARN_ON(!ctx->cur_folio); + ctx->folio_unlocked = false; ret = iomap_readpage_iter(iter, ctx); if (ret) return ret; -- 2.47.3