From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-362987-1516223125-2-9587381255310187147 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-usb-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1516223124; b=PxKabzUle6fH7Zkd06hpG7pZARSe6SD+pScr0pbwR053g1V mRxqwgOlQRUi+w/hRPftiOcfk46lxo81oJKK+4ojjhH4nHesj34fCySXcJHj3sZe lOR9vT8/7npghapaD23PP1aPNc5SwbonhHVFUPE2oHYx7F3zMCKtlIPI7MBZxIWi e2Vf9j8UGNmPBOuyjnmbnGk/0lM6AC3qtrNZNR8vC5vRJCEJDncefirHuk8w9n54 0sh8waExwgQX5e41gRYTOftUrZgTg8YNWV4aE0c1HliAVdHjyCA7wzgczP6tQbBL ZyYgd1LiRjKDry7uFCvRiBjzW+FYQ/ySGIxD8FA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:sender:list-id; s=arctest; t=1516223124; bh=/6MCQxrD4QMB+HAeMEYE/hjF3Hq+Wzq6rFGKjB2lT/Y=; b=VgoWBqmyW0D/ k46m7igp23K/EfVSveMU21kjm1WniBPGpe18Eqxki8fnQOT9QWqxgtDV3h1VQ90W u3LE9YZRLE7OC+lPWYL5mZ7zwqHtptTwAPcEyqB3U3AcUMn36BLcs9b1AfPYv4fe 7jSNMJCsP4KlRXD6QwmsNl9Pn6pN44V+vJlrn6hXu7qGzYccc2yqaltLMGUPIVE4 FC5018RctfCbvtfHYrcriP4bc6qntAkxnftDwq8ic+7EXZ+XRu26Jur3Yen82ka/ qwtHRVVenaBTH2ak4UrR/TnqEmZxSTv6am+0FTJb52dRyug2jMUnM0xAU2CkqNhv sen3lMW1hA== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=fail (message has been altered; 2048-bit rsa key sha256) header.d=infradead.org header.i=@infradead.org header.b=fBRusbgX x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=bombadil.20170209; dmarc=none (p=none,has-list-id=yes,d=none) header.from=infradead.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-usb-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=infradead.org header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=fail (message has been altered; 2048-bit rsa key sha256) header.d=infradead.org header.i=@infradead.org header.b=fBRusbgX x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=bombadil.20170209; dmarc=none (p=none,has-list-id=yes,d=none) header.from=infradead.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-usb-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=infradead.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754889AbeAQVEv (ORCPT ); Wed, 17 Jan 2018 16:04:51 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:39739 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753533AbeAQUWe (ORCPT ); Wed, 17 Jan 2018 15:22:34 -0500 From: Matthew Wilcox To: linux-kernel@vger.kernel.org Cc: Matthew Wilcox , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-nilfs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-usb@vger.kernel.org, Bjorn Andersson , Stefano Stabellini , iommu@lists.linux-foundation.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, intel-gfx@lists.freedesktop.org, cgroups@vger.kernel.org, linux-sh@vger.kernel.org, David Howells Subject: [PATCH v6 23/99] page cache: Add page_cache_range_empty function Date: Wed, 17 Jan 2018 12:20:47 -0800 Message-Id: <20180117202203.19756-24-willy@infradead.org> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180117202203.19756-1-willy@infradead.org> References: <20180117202203.19756-1-willy@infradead.org> Sender: linux-usb-owner@vger.kernel.org X-Mailing-List: linux-usb@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Matthew Wilcox btrfs has its own custom function for determining whether the page cache has any pages in a particular range. Move this functionality to the page cache, and call it from btrfs. Signed-off-by: Matthew Wilcox --- fs/btrfs/btrfs_inode.h | 7 ++++- fs/btrfs/inode.c | 70 ------------------------------------------------- include/linux/pagemap.h | 2 ++ mm/filemap.c | 26 ++++++++++++++++++ 4 files changed, 34 insertions(+), 71 deletions(-) diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h index 63f0ccc92a71..a48bd6e0a0bb 100644 --- a/fs/btrfs/btrfs_inode.h +++ b/fs/btrfs/btrfs_inode.h @@ -365,6 +365,11 @@ static inline void btrfs_print_data_csum_error(struct btrfs_inode *inode, logical_start, csum, csum_expected, mirror_num); } -bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end); +static inline bool btrfs_page_exists_in_range(struct inode *inode, + loff_t start, loff_t end) +{ + return page_cache_range_empty(inode->i_mapping, start >> PAGE_SHIFT, + end >> PAGE_SHIFT); +} #endif diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index dbdb5bf6bca1..d7d2c556d5a2 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7541,76 +7541,6 @@ noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len, return ret; } -bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end) -{ - struct radix_tree_root *root = &inode->i_mapping->pages; - bool found = false; - void **pagep = NULL; - struct page *page = NULL; - unsigned long start_idx; - unsigned long end_idx; - - start_idx = start >> PAGE_SHIFT; - - /* - * end is the last byte in the last page. end == start is legal - */ - end_idx = end >> PAGE_SHIFT; - - rcu_read_lock(); - - /* Most of the code in this while loop is lifted from - * find_get_page. It's been modified to begin searching from a - * page and return just the first page found in that range. If the - * found idx is less than or equal to the end idx then we know that - * a page exists. If no pages are found or if those pages are - * outside of the range then we're fine (yay!) */ - while (page == NULL && - radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) { - page = radix_tree_deref_slot(pagep); - if (unlikely(!page)) - break; - - if (radix_tree_exception(page)) { - if (radix_tree_deref_retry(page)) { - page = NULL; - continue; - } - /* - * Otherwise, shmem/tmpfs must be storing a swap entry - * here so return it without attempting to raise page - * count. - */ - page = NULL; - break; /* TODO: Is this relevant for this use case? */ - } - - if (!page_cache_get_speculative(page)) { - page = NULL; - continue; - } - - /* - * Has the page moved? - * This is part of the lockless pagecache protocol. See - * include/linux/pagemap.h for details. - */ - if (unlikely(page != *pagep)) { - put_page(page); - page = NULL; - } - } - - if (page) { - if (page->index <= end_idx) - found = true; - put_page(page); - } - - rcu_read_unlock(); - return found; -} - static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend, struct extent_state **cached_state, int writing) { diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 0db127c3ccac..34d4fa3ad1c5 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -245,6 +245,8 @@ pgoff_t page_cache_next_gap(struct address_space *mapping, pgoff_t index, unsigned long max_scan); pgoff_t page_cache_prev_gap(struct address_space *mapping, pgoff_t index, unsigned long max_scan); +bool page_cache_range_empty(struct address_space *mapping, + pgoff_t index, pgoff_t max); #define FGP_ACCESSED 0x00000001 #define FGP_LOCK 0x00000002 diff --git a/mm/filemap.c b/mm/filemap.c index 146e8ec16ec0..f1b4480723dd 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1398,6 +1398,32 @@ pgoff_t page_cache_prev_gap(struct address_space *mapping, } EXPORT_SYMBOL(page_cache_prev_gap); +bool page_cache_range_empty(struct address_space *mapping, pgoff_t index, + pgoff_t max) +{ + struct page *page; + XA_STATE(xas, &mapping->pages, index); + + rcu_read_lock(); + do { + page = xas_find(&xas, max); + if (xas_retry(&xas, page)) + continue; + /* Shadow entries don't count */ + if (xa_is_value(page)) + continue; + /* + * We don't need to try to pin this page; we're about to + * release the RCU lock anyway. It is enough to know that + * there was a page here recently. + */ + } while (0); + rcu_read_unlock(); + + return page != NULL; +} +EXPORT_SYMBOL_GPL(page_cache_range_empty); + /** * find_get_entry - find and get a page cache entry * @mapping: the address_space to search -- 2.15.1