From patchwork Mon Dec 18 15:35:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13497143 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB53A5A87E; Mon, 18 Dec 2023 15:36:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="C5A4jUNK" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=vvqaN8/KIqeuNXG6MsZVXoxWgrAefdh1jtznLiH0jnU=; b=C5A4jUNKNWWGNM0AFYi1+TbZqg OyJLFLMAYeRWAkGFHpJj2/i2TpKNAExClZQ0eq/kfZp9NcqLA2do4BbRXo2Q4W+iK4j5Vs5EGWTtw cidcKA8PuBHBAzMjolCFFwvjF1I65aziLi6OSncFKhd+PQGJunCSWzOvrXiVNjvRdL+5XxP+vGK8s 5lB8Xhy8YqBjIl7CVAQyC5btI+HQsTN1MM7VZBSIoR4vpfh7l2M+kWRPnHGFvl25PWqUT6OFS6ICi R5oHvPfCAlXyzNuVQr2cvIxcGzsS5vrPEMkOuUUNuuUzCVzHfnUMHd5Uzh71D7Wv6+5fte9QYjw/K yYSn0SnQ==; Received: from 2a02-8389-2341-5b80-39d3-4735-9a3c-88d8.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:39d3:4735:9a3c:88d8] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rFFf9-00BEMU-2Y; Mon, 18 Dec 2023 15:36:12 +0000 From: Christoph Hellwig To: linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , Jan Kara , David Howells , Brian Foster , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 06/17] writeback: Factor out writeback_finish() Date: Mon, 18 Dec 2023 16:35:42 +0100 Message-Id: <20231218153553.807799-7-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231218153553.807799-1-hch@lst.de> References: <20231218153553.807799-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html From: "Matthew Wilcox (Oracle)" Instead of having a 'done' variable that controls the nested loops, have a writeback_finish() that can be returned directly. This involves keeping more things in writeback_control, but it's just moving stuff allocated on the stack to being allocated slightly earlier on the stack. Signed-off-by: Matthew Wilcox (Oracle) [hch: heavily rebased, reordered and commented struct writeback_control] Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara --- include/linux/writeback.h | 6 +++ mm/page-writeback.c | 79 ++++++++++++++++++++------------------- 2 files changed, 47 insertions(+), 38 deletions(-) diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 833ec38fc3e0c9..390f2dd03cf27e 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -11,6 +11,7 @@ #include #include #include +#include struct bio; @@ -40,6 +41,7 @@ enum writeback_sync_modes { * in a manner such that unspecified fields are set to zero. */ struct writeback_control { + /* public fields that can be set and/or consumed by the caller: */ long nr_to_write; /* Write this many pages, and decrement this for each page written */ long pages_skipped; /* Pages which were not written */ @@ -77,6 +79,10 @@ struct writeback_control { */ struct swap_iocb **swap_plug; + /* internal fields used by the ->writepages implementation: */ + struct folio_batch fbatch; + int err; + #ifdef CONFIG_CGROUP_WRITEBACK struct bdi_writeback *wb; /* wb this writeback is issued under */ struct inode *inode; /* inode being written out */ diff --git a/mm/page-writeback.c b/mm/page-writeback.c index c798c0d6d0abb4..564d5faf562ba7 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2360,6 +2360,29 @@ void tag_pages_for_writeback(struct address_space *mapping, } EXPORT_SYMBOL(tag_pages_for_writeback); +static void writeback_finish(struct address_space *mapping, + struct writeback_control *wbc, pgoff_t done_index) +{ + folio_batch_release(&wbc->fbatch); + + /* + * For range cyclic writeback we need to remember where we stopped so + * that we can continue there next time we are called. If we hit the + * last page and there is more work to be done, wrap back to the start + * of the file. + * + * For non-cyclic writeback we always start looking up at the beginning + * of the file if we are called again, which can only happen due to + * -ENOMEM from the file system. + */ + if (wbc->range_cyclic) { + if (wbc->err || wbc->nr_to_write <= 0) + mapping->writeback_index = done_index; + else + mapping->writeback_index = 0; + } +} + /** * write_cache_pages - walk the list of dirty pages of the given address space and write all of them. * @mapping: address space structure to write @@ -2395,17 +2418,12 @@ int write_cache_pages(struct address_space *mapping, struct writeback_control *wbc, writepage_t writepage, void *data) { - int ret = 0; - int done = 0; int error; - struct folio_batch fbatch; int nr_folios; pgoff_t index; pgoff_t end; /* Inclusive */ - pgoff_t done_index; xa_mark_t tag; - folio_batch_init(&fbatch); if (wbc->range_cyclic) { index = mapping->writeback_index; /* prev offset */ end = -1; @@ -2419,22 +2437,23 @@ int write_cache_pages(struct address_space *mapping, } else { tag = PAGECACHE_TAG_DIRTY; } - done_index = index; - while (!done && (index <= end)) { + + folio_batch_init(&wbc->fbatch); + wbc->err = 0; + + while (index <= end) { int i; nr_folios = filemap_get_folios_tag(mapping, &index, end, - tag, &fbatch); + tag, &wbc->fbatch); if (nr_folios == 0) break; for (i = 0; i < nr_folios; i++) { - struct folio *folio = fbatch.folios[i]; + struct folio *folio = wbc->fbatch.folios[i]; unsigned long nr; - done_index = folio->index; - folio_lock(folio); /* @@ -2481,6 +2500,9 @@ int write_cache_pages(struct address_space *mapping, folio_unlock(folio); error = 0; } + + if (error && !wbc->err) + wbc->err = error; /* * For integrity sync we have to keep going until we @@ -2496,38 +2518,19 @@ int write_cache_pages(struct address_space *mapping, * off and media errors won't choke writeout for the * entire file. */ - if (error && !ret) - ret = error; - if (wbc->sync_mode == WB_SYNC_NONE) { - if (ret || wbc->nr_to_write <= 0) { - done_index = folio->index + nr; - done = 1; - break; - } + if (wbc->sync_mode == WB_SYNC_NONE && + (wbc->err || wbc->nr_to_write <= 0)) { + writeback_finish(mapping, wbc, + folio->index + nr); + return error; } } - folio_batch_release(&fbatch); + folio_batch_release(&wbc->fbatch); cond_resched(); } - /* - * For range cyclic writeback we need to remember where we stopped so - * that we can continue there next time we are called. If we hit the - * last page and there is more work to be done, wrap back to the start - * of the file. - * - * For non-cyclic writeback we always start looking up at the beginning - * of the file if we are called again, which can only happen due to - * -ENOMEM from the file system. - */ - if (wbc->range_cyclic) { - if (done) - mapping->writeback_index = done_index; - else - mapping->writeback_index = 0; - } - - return ret; + writeback_finish(mapping, wbc, 0); + return 0; } EXPORT_SYMBOL(write_cache_pages);