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Tue, 17 Dec 2019 09:31:24 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xBH9SjuA050258; Tue, 17 Dec 2019 09:31:23 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3030.oracle.com with ESMTP id 2wxm4vcka5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 17 Dec 2019 09:31:23 +0000 Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id xBH9VNWb026277; Tue, 17 Dec 2019 09:31:23 GMT Received: from [10.190.130.61] (/192.188.170.109) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 17 Dec 2019 01:31:22 -0800 Subject: Re: [PATCH] btrfs: use helper to zero end of last page To: David Sterba , linux-btrfs@vger.kernel.org References: <20191216185038.14913-1-dsterba@suse.com> From: Anand Jain Message-ID: <4ca3c941-c3c0-2128-e206-01a9eb96953e@oracle.com> Date: Tue, 17 Dec 2019 17:31:14 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20191216185038.14913-1-dsterba@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9473 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1912170083 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9473 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1912170083 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 17/12/19 2:50 AM, David Sterba wrote: > The zero_user_segment is open coded in several places, we should use the > helper. btrfs_page_mkwrite uses kmap/kunmap but replacing them by > _atomic variants is not a problem as they're more restrictive than > required. > > Signed-off-by: David Sterba > --- > fs/btrfs/compression.c | 15 ++------------- > fs/btrfs/extent_io.c | 39 +++++++-------------------------------- > fs/btrfs/inode.c | 10 +++------- > 3 files changed, 12 insertions(+), 52 deletions(-) > > diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c > index ed05e5277399..299fcfdfb10f 100644 > --- a/fs/btrfs/compression.c > +++ b/fs/btrfs/compression.c > @@ -602,19 +602,8 @@ static noinline int add_ra_bio_pages(struct inode *inode, > } > free_extent_map(em); > > - if (page->index == end_index) { > - char *userpage; > - size_t zero_offset = offset_in_page(isize); > - > - if (zero_offset) { > - int zeros; > - zeros = PAGE_SIZE - zero_offset; > - userpage = kmap_atomic(page); > - memset(userpage + zero_offset, 0, zeros); > - flush_dcache_page(page); > - kunmap_atomic(userpage); > - } > - } > + if (page->index == end_index) > + zero_user_segment(page, offset_in_page(isize), PAGE_SIZE); > Before we zero-ed only when the page offset is not starting at 0. Can you confirm and update the change log if that is ok. > ret = bio_add_page(cb->orig_bio, page, > PAGE_SIZE, 0); > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > index 394beb474a69..d6b3af7f1675 100644 > --- a/fs/btrfs/extent_io.c > +++ b/fs/btrfs/extent_io.c > @@ -3093,31 +3093,18 @@ static int __do_readpage(struct extent_io_tree *tree, > } > } > > - if (page->index == last_byte >> PAGE_SHIFT) { > - char *userpage; > - size_t zero_offset = offset_in_page(last_byte); > - > - if (zero_offset) { > - iosize = PAGE_SIZE - zero_offset; > - userpage = kmap_atomic(page); > - memset(userpage + zero_offset, 0, iosize); > - flush_dcache_page(page); > - kunmap_atomic(userpage); > - } > - } > + if (page->index == last_byte >> PAGE_SHIFT) > + zero_user_segment(page, offset_in_page(last_byte), PAGE_SIZE); > + Here also. Thanks, Anand > while (cur <= end) { > bool force_bio_submit = false; > u64 offset; > > if (cur >= last_byte) { > - char *userpage; > struct extent_state *cached = NULL; > > + zero_user_segment(page, pg_offset, PAGE_SIZE); > iosize = PAGE_SIZE - pg_offset; > - userpage = kmap_atomic(page); > - memset(userpage + pg_offset, 0, iosize); > - flush_dcache_page(page); > - kunmap_atomic(userpage); > set_extent_uptodate(tree, cur, cur + iosize - 1, > &cached, GFP_NOFS); > unlock_extent_cached(tree, cur, > @@ -3202,14 +3189,9 @@ static int __do_readpage(struct extent_io_tree *tree, > > /* we've found a hole, just zero and go on */ > if (block_start == EXTENT_MAP_HOLE) { > - char *userpage; > struct extent_state *cached = NULL; > > - userpage = kmap_atomic(page); > - memset(userpage + pg_offset, 0, iosize); > - flush_dcache_page(page); > - kunmap_atomic(userpage); > - > + zero_user_segment(page, pg_offset, pg_offset + iosize); > set_extent_uptodate(tree, cur, cur + iosize - 1, > &cached, GFP_NOFS); > unlock_extent_cached(tree, cur, > @@ -3564,15 +3546,8 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc, > return 0; > } > > - if (page->index == end_index) { > - char *userpage; > - > - userpage = kmap_atomic(page); > - memset(userpage + pg_offset, 0, > - PAGE_SIZE - pg_offset); > - kunmap_atomic(userpage); > - flush_dcache_page(page); > - } > + if (page->index == end_index) > + zero_user_segment(page, pg_offset, PAGE_SIZE); > > set_page_extent_mapped(page); > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index f27377d8ec55..24337de25a8b 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -8308,7 +8308,6 @@ vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf) > struct btrfs_ordered_extent *ordered; > struct extent_state *cached_state = NULL; > struct extent_changeset *data_reserved = NULL; > - char *kaddr; > unsigned long zero_start; > loff_t size; > vm_fault_t ret; > @@ -8414,12 +8413,9 @@ vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf) > else > zero_start = PAGE_SIZE; > > - if (zero_start != PAGE_SIZE) { > - kaddr = kmap(page); > - memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start); > - flush_dcache_page(page); > - kunmap(page); > - } > + if (zero_start != PAGE_SIZE) > + zero_user_segment(page, zero_start, PAGE_SIZE); > + > ClearPageChecked(page); > set_page_dirty(page); > SetPageUptodate(page); >