From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: mm: use readahead_control to pass arguments In this patch, only between __do_page_cache_readahead() and read_pages(), but it will be extended in upcoming patches. The read_pages() function becomes aops centric, as this makes the most sense by the end of the patchset. Link: http://lkml.kernel.org/r/20200414150233.24495-7-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx> Cc: Chao Yu <yuchao0@xxxxxxxxxx> Cc: Cong Wang <xiyou.wangcong@xxxxxxxxx> Cc: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Cc: Dave Chinner <dchinner@xxxxxxxxxx> Cc: Eric Biggers <ebiggers@xxxxxxxxxx> Cc: Gao Xiang <gaoxiang25@xxxxxxxxxx> Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Cc: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx> Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Zi Yan <ziy@xxxxxxxxxx> Cc: Miklos Szeredi <mszeredi@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/readahead.c | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-) --- a/mm/readahead.c~mm-use-readahead_control-to-pass-arguments +++ a/mm/readahead.c @@ -113,29 +113,32 @@ int read_cache_pages(struct address_spac EXPORT_SYMBOL(read_cache_pages); -static void read_pages(struct address_space *mapping, struct file *filp, - struct list_head *pages, unsigned int nr_pages, gfp_t gfp) +static void read_pages(struct readahead_control *rac, struct list_head *pages, + gfp_t gfp) { + const struct address_space_operations *aops = rac->mapping->a_ops; struct blk_plug plug; unsigned page_idx; - if (!nr_pages) + if (!readahead_count(rac)) return; blk_start_plug(&plug); - if (mapping->a_ops->readpages) { - mapping->a_ops->readpages(filp, mapping, pages, nr_pages); + if (aops->readpages) { + aops->readpages(rac->file, rac->mapping, pages, + readahead_count(rac)); /* Clean up the remaining pages */ put_pages_list(pages); goto out; } - for (page_idx = 0; page_idx < nr_pages; page_idx++) { + for (page_idx = 0; page_idx < readahead_count(rac); page_idx++) { struct page *page = lru_to_page(pages); list_del(&page->lru); - if (!add_to_page_cache_lru(page, mapping, page->index, gfp)) - mapping->a_ops->readpage(filp, page); + if (!add_to_page_cache_lru(page, rac->mapping, page->index, + gfp)) + aops->readpage(rac->file, page); put_page(page); } @@ -143,6 +146,7 @@ out: blk_finish_plug(&plug); BUG_ON(!list_empty(pages)); + rac->_nr_pages = 0; } /* @@ -160,9 +164,12 @@ void __do_page_cache_readahead(struct ad unsigned long end_index; /* The last page we want to read */ LIST_HEAD(page_pool); int page_idx; - unsigned int nr_pages = 0; loff_t isize = i_size_read(inode); gfp_t gfp_mask = readahead_gfp_mask(mapping); + struct readahead_control rac = { + .mapping = mapping, + .file = filp, + }; if (isize == 0) return; @@ -185,9 +192,7 @@ void __do_page_cache_readahead(struct ad * contiguous pages before continuing with the next * batch. */ - read_pages(mapping, filp, &page_pool, nr_pages, - gfp_mask); - nr_pages = 0; + read_pages(&rac, &page_pool, gfp_mask); continue; } @@ -198,7 +203,7 @@ void __do_page_cache_readahead(struct ad list_add(&page->lru, &page_pool); if (page_idx == nr_to_read - lookahead_size) SetPageReadahead(page); - nr_pages++; + rac._nr_pages++; } /* @@ -206,7 +211,7 @@ void __do_page_cache_readahead(struct ad * uptodate then the caller will launch readpage again, and * will then handle the error. */ - read_pages(mapping, filp, &page_pool, nr_pages, gfp_mask); + read_pages(&rac, &page_pool, gfp_mask); } /* _
