From: "Matthew Wilcox (Oracle)" <wi...@infradead.org> Implement the new readahead aop and convert all callers (block_dev, exfat, ext2, fat, gfs2, hpfs, isofs, jfs, nilfs2, ocfs2, omfs, qnx6, reiserfs & udf). The callers are all trivial except for GFS2 & OCFS2.
Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org> Reviewed-by: Junxiao Bi <junxiao...@oracle.com> # ocfs2 Reviewed-by: Joseph Qi <joseph...@linux.alibaba.com> # ocfs2 Reviewed-by: Dave Chinner <dchin...@redhat.com> Reviewed-by: John Hubbard <jhubb...@nvidia.com> Reviewed-by: Christoph Hellwig <h...@lst.de> Reviewed-by: William Kucharski <william.kuchar...@oracle.com> --- drivers/staging/exfat/exfat_super.c | 7 +++--- fs/block_dev.c | 7 +++--- fs/ext2/inode.c | 10 +++----- fs/fat/inode.c | 7 +++--- fs/gfs2/aops.c | 23 ++++++----------- fs/hpfs/file.c | 7 +++--- fs/iomap/buffered-io.c | 2 +- fs/isofs/inode.c | 7 +++--- fs/jfs/inode.c | 7 +++--- fs/mpage.c | 38 +++++++++-------------------- fs/nilfs2/inode.c | 15 +++--------- fs/ocfs2/aops.c | 34 ++++++++++---------------- fs/omfs/file.c | 7 +++--- fs/qnx6/inode.c | 7 +++--- fs/reiserfs/inode.c | 8 +++--- fs/udf/inode.c | 7 +++--- include/linux/mpage.h | 4 +-- mm/migrate.c | 2 +- 18 files changed, 73 insertions(+), 126 deletions(-) diff --git a/drivers/staging/exfat/exfat_super.c b/drivers/staging/exfat/exfat_super.c index b81d2a87b82e..96aad9b16d31 100644 --- a/drivers/staging/exfat/exfat_super.c +++ b/drivers/staging/exfat/exfat_super.c @@ -3002,10 +3002,9 @@ static int exfat_readpage(struct file *file, struct page *page) return mpage_readpage(page, exfat_get_block); } -static int exfat_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned int nr_pages) +static void exfat_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, exfat_get_block); + mpage_readahead(rac, exfat_get_block); } static int exfat_writepage(struct page *page, struct writeback_control *wbc) @@ -3104,7 +3103,7 @@ static sector_t _exfat_bmap(struct address_space *mapping, sector_t block) static const struct address_space_operations exfat_aops = { .readpage = exfat_readpage, - .readpages = exfat_readpages, + .readahead = exfat_readahead, .writepage = exfat_writepage, .writepages = exfat_writepages, .write_begin = exfat_write_begin, diff --git a/fs/block_dev.c b/fs/block_dev.c index 69bf2fb6f7cd..2fd9c7bd61f6 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -614,10 +614,9 @@ static int blkdev_readpage(struct file * file, struct page * page) return block_read_full_page(page, blkdev_get_block); } -static int blkdev_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void blkdev_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, blkdev_get_block); + mpage_readahead(rac, blkdev_get_block); } static int blkdev_write_begin(struct file *file, struct address_space *mapping, @@ -2062,7 +2061,7 @@ static int blkdev_writepages(struct address_space *mapping, static const struct address_space_operations def_blk_aops = { .readpage = blkdev_readpage, - .readpages = blkdev_readpages, + .readahead = blkdev_readahead, .writepage = blkdev_writepage, .write_begin = blkdev_write_begin, .write_end = blkdev_write_end, diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index c885cf7d724b..2875c0a705b5 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -877,11 +877,9 @@ static int ext2_readpage(struct file *file, struct page *page) return mpage_readpage(page, ext2_get_block); } -static int -ext2_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void ext2_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, ext2_get_block); + mpage_readahead(rac, ext2_get_block); } static int @@ -967,7 +965,7 @@ ext2_dax_writepages(struct address_space *mapping, struct writeback_control *wbc const struct address_space_operations ext2_aops = { .readpage = ext2_readpage, - .readpages = ext2_readpages, + .readahead = ext2_readahead, .writepage = ext2_writepage, .write_begin = ext2_write_begin, .write_end = ext2_write_end, @@ -981,7 +979,7 @@ const struct address_space_operations ext2_aops = { const struct address_space_operations ext2_nobh_aops = { .readpage = ext2_readpage, - .readpages = ext2_readpages, + .readahead = ext2_readahead, .writepage = ext2_nobh_writepage, .write_begin = ext2_nobh_write_begin, .write_end = nobh_write_end, diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 594b05ae16c9..3496f5fc3e6d 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -210,10 +210,9 @@ static int fat_readpage(struct file *file, struct page *page) return mpage_readpage(page, fat_get_block); } -static int fat_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void fat_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, fat_get_block); + mpage_readahead(rac, fat_get_block); } static void fat_write_failed(struct address_space *mapping, loff_t to) @@ -344,7 +343,7 @@ int fat_block_truncate_page(struct inode *inode, loff_t from) static const struct address_space_operations fat_aops = { .readpage = fat_readpage, - .readpages = fat_readpages, + .readahead = fat_readahead, .writepage = fat_writepage, .writepages = fat_writepages, .write_begin = fat_write_begin, diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c index ba83b49ce18c..5e63c13c12c1 100644 --- a/fs/gfs2/aops.c +++ b/fs/gfs2/aops.c @@ -577,7 +577,7 @@ int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos, } /** - * gfs2_readpages - Read a bunch of pages at once + * gfs2_readahead - Read a bunch of pages at once * @file: The file to read from * @mapping: Address space info * @pages: List of pages to read @@ -590,31 +590,24 @@ int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos, * obviously not something we'd want to do on too regular a basis. * Any I/O we ignore at this time will be done via readpage later. * 2. We don't handle stuffed files here we let readpage do the honours. - * 3. mpage_readpages() does most of the heavy lifting in the common case. + * 3. mpage_readahead() does most of the heavy lifting in the common case. * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places. */ -static int gfs2_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void gfs2_readahead(struct readahead_control *rac) { - struct inode *inode = mapping->host; + struct inode *inode = rac->mapping->host; struct gfs2_inode *ip = GFS2_I(inode); - struct gfs2_sbd *sdp = GFS2_SB(inode); struct gfs2_holder gh; - int ret; gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh); - ret = gfs2_glock_nq(&gh); - if (unlikely(ret)) + if (gfs2_glock_nq(&gh)) goto out_uninit; if (!gfs2_is_stuffed(ip)) - ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map); + mpage_readahead(rac, gfs2_block_map); gfs2_glock_dq(&gh); out_uninit: gfs2_holder_uninit(&gh); - if (unlikely(gfs2_withdrawn(sdp))) - ret = -EIO; - return ret; } /** @@ -828,7 +821,7 @@ static const struct address_space_operations gfs2_aops = { .writepage = gfs2_writepage, .writepages = gfs2_writepages, .readpage = gfs2_readpage, - .readpages = gfs2_readpages, + .readahead = gfs2_readahead, .bmap = gfs2_bmap, .invalidatepage = gfs2_invalidatepage, .releasepage = gfs2_releasepage, @@ -842,7 +835,7 @@ static const struct address_space_operations gfs2_jdata_aops = { .writepage = gfs2_jdata_writepage, .writepages = gfs2_jdata_writepages, .readpage = gfs2_readpage, - .readpages = gfs2_readpages, + .readahead = gfs2_readahead, .set_page_dirty = jdata_set_page_dirty, .bmap = gfs2_bmap, .invalidatepage = gfs2_invalidatepage, diff --git a/fs/hpfs/file.c b/fs/hpfs/file.c index b36abf9cb345..2de0d3492d15 100644 --- a/fs/hpfs/file.c +++ b/fs/hpfs/file.c @@ -125,10 +125,9 @@ static int hpfs_writepage(struct page *page, struct writeback_control *wbc) return block_write_full_page(page, hpfs_get_block, wbc); } -static int hpfs_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void hpfs_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, hpfs_get_block); + mpage_readahead(rac, hpfs_get_block); } static int hpfs_writepages(struct address_space *mapping, @@ -198,7 +197,7 @@ static int hpfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, const struct address_space_operations hpfs_aops = { .readpage = hpfs_readpage, .writepage = hpfs_writepage, - .readpages = hpfs_readpages, + .readahead = hpfs_readahead, .writepages = hpfs_writepages, .write_begin = hpfs_write_begin, .write_end = hpfs_write_end, diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 7c84c4c027c4..cb3511eb152a 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -359,7 +359,7 @@ iomap_readpage(struct page *page, const struct iomap_ops *ops) } /* - * Just like mpage_readpages and block_read_full_page we always + * Just like mpage_readahead and block_read_full_page we always * return 0 and just mark the page as PageError on errors. This * should be cleaned up all through the stack eventually. */ diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c index 62c0462dc89f..95b1f377ad09 100644 --- a/fs/isofs/inode.c +++ b/fs/isofs/inode.c @@ -1185,10 +1185,9 @@ static int isofs_readpage(struct file *file, struct page *page) return mpage_readpage(page, isofs_get_block); } -static int isofs_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void isofs_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, isofs_get_block); + mpage_readahead(rac, isofs_get_block); } static sector_t _isofs_bmap(struct address_space *mapping, sector_t block) @@ -1198,7 +1197,7 @@ static sector_t _isofs_bmap(struct address_space *mapping, sector_t block) static const struct address_space_operations isofs_aops = { .readpage = isofs_readpage, - .readpages = isofs_readpages, + .readahead = isofs_readahead, .bmap = _isofs_bmap }; diff --git a/fs/jfs/inode.c b/fs/jfs/inode.c index 9486afcdac76..6f65bfa9f18d 100644 --- a/fs/jfs/inode.c +++ b/fs/jfs/inode.c @@ -296,10 +296,9 @@ static int jfs_readpage(struct file *file, struct page *page) return mpage_readpage(page, jfs_get_block); } -static int jfs_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void jfs_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, jfs_get_block); + mpage_readahead(rac, jfs_get_block); } static void jfs_write_failed(struct address_space *mapping, loff_t to) @@ -358,7 +357,7 @@ static ssize_t jfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) const struct address_space_operations jfs_aops = { .readpage = jfs_readpage, - .readpages = jfs_readpages, + .readahead = jfs_readahead, .writepage = jfs_writepage, .writepages = jfs_writepages, .write_begin = jfs_write_begin, diff --git a/fs/mpage.c b/fs/mpage.c index ccba3c4c4479..830e6cc2a9e7 100644 --- a/fs/mpage.c +++ b/fs/mpage.c @@ -91,7 +91,7 @@ mpage_alloc(struct block_device *bdev, } /* - * support function for mpage_readpages. The fs supplied get_block might + * support function for mpage_readahead. The fs supplied get_block might * return an up to date buffer. This is used to map that buffer into * the page, which allows readpage to avoid triggering a duplicate call * to get_block. @@ -338,13 +338,8 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args) } /** - * mpage_readpages - populate an address space with some pages & start reads against them - * @mapping: the address_space - * @pages: The address of a list_head which contains the target pages. These - * pages have their ->index populated and are otherwise uninitialised. - * The page at @pages->prev has the lowest file offset, and reads should be - * issued in @pages->prev to @pages->next order. - * @nr_pages: The number of pages at *@pages + * mpage_readahead - start reads against pages + * @rac: Describes which pages to read. * @get_block: The filesystem's block mapper function. * * This function walks the pages and the blocks within each page, building and @@ -381,36 +376,25 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args) * * This all causes the disk requests to be issued in the correct order. */ -int -mpage_readpages(struct address_space *mapping, struct list_head *pages, - unsigned nr_pages, get_block_t get_block) +void mpage_readahead(struct readahead_control *rac, get_block_t get_block) { + struct page *page; struct mpage_readpage_args args = { .get_block = get_block, .is_readahead = true, }; - unsigned page_idx; - - for (page_idx = 0; page_idx < nr_pages; page_idx++) { - struct page *page = lru_to_page(pages); + while ((page = readahead_page(rac))) { prefetchw(&page->flags); - list_del(&page->lru); - if (!add_to_page_cache_lru(page, mapping, - page->index, - readahead_gfp_mask(mapping))) { - args.page = page; - args.nr_pages = nr_pages - page_idx; - args.bio = do_mpage_readpage(&args); - } + args.page = page; + args.nr_pages = readahead_count(rac); + args.bio = do_mpage_readpage(&args); put_page(page); } - BUG_ON(!list_empty(pages)); if (args.bio) mpage_bio_submit(REQ_OP_READ, REQ_RAHEAD, args.bio); - return 0; } -EXPORT_SYMBOL(mpage_readpages); +EXPORT_SYMBOL(mpage_readahead); /* * This isn't called much at all @@ -563,7 +547,7 @@ static int __mpage_writepage(struct page *page, struct writeback_control *wbc, * Page has buffers, but they are all unmapped. The page was * created by pagein or read over a hole which was handled by * block_read_full_page(). If this address_space is also - * using mpage_readpages then this can rarely happen. + * using mpage_readahead then this can rarely happen. */ goto confused; } diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c index 671085512e0f..ceeb3b441844 100644 --- a/fs/nilfs2/inode.c +++ b/fs/nilfs2/inode.c @@ -145,18 +145,9 @@ static int nilfs_readpage(struct file *file, struct page *page) return mpage_readpage(page, nilfs_get_block); } -/** - * nilfs_readpages() - implement readpages() method of nilfs_aops {} - * address_space_operations. - * @file - file struct of the file to be read - * @mapping - address_space struct used for reading multiple pages - * @pages - the pages to be read - * @nr_pages - number of pages to be read - */ -static int nilfs_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned int nr_pages) +static void nilfs_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, nilfs_get_block); + mpage_readahead(rac, nilfs_get_block); } static int nilfs_writepages(struct address_space *mapping, @@ -308,7 +299,7 @@ const struct address_space_operations nilfs_aops = { .readpage = nilfs_readpage, .writepages = nilfs_writepages, .set_page_dirty = nilfs_set_page_dirty, - .readpages = nilfs_readpages, + .readahead = nilfs_readahead, .write_begin = nilfs_write_begin, .write_end = nilfs_write_end, /* .releasepage = nilfs_releasepage, */ diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 3a67a6518ddf..3bfb4147895a 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -350,14 +350,11 @@ static int ocfs2_readpage(struct file *file, struct page *page) * grow out to a tree. If need be, detecting boundary extents could * trivially be added in a future version of ocfs2_get_block(). */ -static int ocfs2_readpages(struct file *filp, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void ocfs2_readahead(struct readahead_control *rac) { - int ret, err = -EIO; - struct inode *inode = mapping->host; + int ret; + struct inode *inode = rac->mapping->host; struct ocfs2_inode_info *oi = OCFS2_I(inode); - loff_t start; - struct page *last; /* * Use the nonblocking flag for the dlm code to avoid page @@ -365,36 +362,31 @@ static int ocfs2_readpages(struct file *filp, struct address_space *mapping, */ ret = ocfs2_inode_lock_full(inode, NULL, 0, OCFS2_LOCK_NONBLOCK); if (ret) - return err; + return; - if (down_read_trylock(&oi->ip_alloc_sem) == 0) { - ocfs2_inode_unlock(inode, 0); - return err; - } + if (down_read_trylock(&oi->ip_alloc_sem) == 0) + goto out_unlock; /* * Don't bother with inline-data. There isn't anything * to read-ahead in that case anyway... */ if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) - goto out_unlock; + goto out_up; /* * Check whether a remote node truncated this file - we just * drop out in that case as it's not worth handling here. */ - last = lru_to_page(pages); - start = (loff_t)last->index << PAGE_SHIFT; - if (start >= i_size_read(inode)) - goto out_unlock; + if (readahead_pos(rac) >= i_size_read(inode)) + goto out_up; - err = mpage_readpages(mapping, pages, nr_pages, ocfs2_get_block); + mpage_readahead(rac, ocfs2_get_block); -out_unlock: +out_up: up_read(&oi->ip_alloc_sem); +out_unlock: ocfs2_inode_unlock(inode, 0); - - return err; } /* Note: Because we don't support holes, our allocation has @@ -2474,7 +2466,7 @@ static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter) const struct address_space_operations ocfs2_aops = { .readpage = ocfs2_readpage, - .readpages = ocfs2_readpages, + .readahead = ocfs2_readahead, .writepage = ocfs2_writepage, .write_begin = ocfs2_write_begin, .write_end = ocfs2_write_end, diff --git a/fs/omfs/file.c b/fs/omfs/file.c index d640b9388238..d7b5f09d298c 100644 --- a/fs/omfs/file.c +++ b/fs/omfs/file.c @@ -289,10 +289,9 @@ static int omfs_readpage(struct file *file, struct page *page) return block_read_full_page(page, omfs_get_block); } -static int omfs_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void omfs_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, omfs_get_block); + mpage_readahead(rac, omfs_get_block); } static int omfs_writepage(struct page *page, struct writeback_control *wbc) @@ -373,7 +372,7 @@ const struct inode_operations omfs_file_inops = { const struct address_space_operations omfs_aops = { .readpage = omfs_readpage, - .readpages = omfs_readpages, + .readahead = omfs_readahead, .writepage = omfs_writepage, .writepages = omfs_writepages, .write_begin = omfs_write_begin, diff --git a/fs/qnx6/inode.c b/fs/qnx6/inode.c index 345db56c98fd..755293c8c71a 100644 --- a/fs/qnx6/inode.c +++ b/fs/qnx6/inode.c @@ -99,10 +99,9 @@ static int qnx6_readpage(struct file *file, struct page *page) return mpage_readpage(page, qnx6_get_block); } -static int qnx6_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void qnx6_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, qnx6_get_block); + mpage_readahead(rac, qnx6_get_block); } /* @@ -499,7 +498,7 @@ static sector_t qnx6_bmap(struct address_space *mapping, sector_t block) } static const struct address_space_operations qnx6_aops = { .readpage = qnx6_readpage, - .readpages = qnx6_readpages, + .readahead = qnx6_readahead, .bmap = qnx6_bmap }; diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c index 6419e6dacc39..0031070b3692 100644 --- a/fs/reiserfs/inode.c +++ b/fs/reiserfs/inode.c @@ -1160,11 +1160,9 @@ int reiserfs_get_block(struct inode *inode, sector_t block, return retval; } -static int -reiserfs_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void reiserfs_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, reiserfs_get_block); + mpage_readahead(rac, reiserfs_get_block); } /* @@ -3434,7 +3432,7 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr) const struct address_space_operations reiserfs_address_space_operations = { .writepage = reiserfs_writepage, .readpage = reiserfs_readpage, - .readpages = reiserfs_readpages, + .readahead = reiserfs_readahead, .releasepage = reiserfs_releasepage, .invalidatepage = reiserfs_invalidatepage, .write_begin = reiserfs_write_begin, diff --git a/fs/udf/inode.c b/fs/udf/inode.c index e875bc5668ee..adaba8e8b326 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -195,10 +195,9 @@ static int udf_readpage(struct file *file, struct page *page) return mpage_readpage(page, udf_get_block); } -static int udf_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) +static void udf_readahead(struct readahead_control *rac) { - return mpage_readpages(mapping, pages, nr_pages, udf_get_block); + mpage_readahead(rac, udf_get_block); } static int udf_write_begin(struct file *file, struct address_space *mapping, @@ -234,7 +233,7 @@ static sector_t udf_bmap(struct address_space *mapping, sector_t block) const struct address_space_operations udf_aops = { .readpage = udf_readpage, - .readpages = udf_readpages, + .readahead = udf_readahead, .writepage = udf_writepage, .writepages = udf_writepages, .write_begin = udf_write_begin, diff --git a/include/linux/mpage.h b/include/linux/mpage.h index 001f1fcf9836..f4f5e90a6844 100644 --- a/include/linux/mpage.h +++ b/include/linux/mpage.h @@ -13,9 +13,9 @@ #ifdef CONFIG_BLOCK struct writeback_control; +struct readahead_control; -int mpage_readpages(struct address_space *mapping, struct list_head *pages, - unsigned nr_pages, get_block_t get_block); +void mpage_readahead(struct readahead_control *, get_block_t get_block); int mpage_readpage(struct page *page, get_block_t get_block); int mpage_writepages(struct address_space *mapping, struct writeback_control *wbc, get_block_t get_block); diff --git a/mm/migrate.c b/mm/migrate.c index b1092876e537..a32122095702 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1020,7 +1020,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, * to the LRU. Later, when the IO completes the pages are * marked uptodate and unlocked. However, the queueing * could be merging multiple pages for one bio (e.g. - * mpage_readpages). If an allocation happens for the + * mpage_readahead). If an allocation happens for the * second or third page, the process can end up locking * the same page twice and deadlocking. Rather than * trying to be clever about what pages can be locked, -- 2.25.1