From 18772641dbe2c89c6122c603f81f6a9574aee556 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Mon, 1 Aug 2011 21:38:07 -0700 Subject: direct-io: separate map_bh from dio Only a single b_private field in the map_bh buffer head is needed after the submission path. Move map_bh separately to avoid storing this information in the long term slab. This avoids the weird 104 byte hole in struct dio_submit which also needed to be memseted early. Signed-off-by: Andi Kleen Signed-off-by: Christoph Hellwig --- fs/direct-io.c | 66 ++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 37 insertions(+), 29 deletions(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index 6bb04409e725..edf3174afd6a 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -119,6 +119,7 @@ struct dio { loff_t i_size; /* i_size when submitted */ dio_iodone_t *end_io; /* IO completion function */ + void *private; /* copy from map_bh.b_private */ /* BIO completion state */ spinlock_t bio_lock; /* protects BIO fields below */ @@ -133,7 +134,6 @@ struct dio { struct kiocb *iocb; /* kiocb */ ssize_t result; /* IO result */ - struct buffer_head map_bh; /* last get_block() result */ /* * pages[] (and any fields placed after it) are not zeroed out at * allocation time. Don't add new fields after pages[] unless you @@ -301,7 +301,7 @@ static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret, bool is if (dio->end_io && dio->result) { dio->end_io(dio->iocb, offset, transferred, - dio->map_bh.b_private, ret, is_async); + dio->private, ret, is_async); } else { if (is_async) aio_complete(dio->iocb, ret, 0); @@ -574,10 +574,10 @@ static int dio_bio_reap(struct dio *dio, struct dio_submit *sdio) * buffer_mapped(). However the direct-io code will only process holes one * block at a time - it will repeatedly call get_block() as it walks the hole. */ -static int get_more_blocks(struct dio *dio, struct dio_submit *sdio) +static int get_more_blocks(struct dio *dio, struct dio_submit *sdio, + struct buffer_head *map_bh) { int ret; - struct buffer_head *map_bh = &dio->map_bh; sector_t fs_startblk; /* Into file, in filesystem-sized blocks */ unsigned long fs_count; /* Number of filesystem-sized blocks */ unsigned long dio_count;/* Number of dio_block-sized blocks */ @@ -621,6 +621,9 @@ static int get_more_blocks(struct dio *dio, struct dio_submit *sdio) ret = (*sdio->get_block)(dio->inode, fs_startblk, map_bh, create); + + /* Store for completion */ + dio->private = map_bh->b_private; } return ret; } @@ -629,7 +632,7 @@ static int get_more_blocks(struct dio *dio, struct dio_submit *sdio) * There is no bio. Make one now. */ static int dio_new_bio(struct dio *dio, struct dio_submit *sdio, - sector_t start_sector) + sector_t start_sector, struct buffer_head *map_bh) { sector_t sector; int ret, nr_pages; @@ -638,10 +641,10 @@ static int dio_new_bio(struct dio *dio, struct dio_submit *sdio, if (ret) goto out; sector = start_sector << (sdio->blkbits - 9); - nr_pages = min(sdio->pages_in_io, bio_get_nr_vecs(dio->map_bh.b_bdev)); + nr_pages = min(sdio->pages_in_io, bio_get_nr_vecs(map_bh->b_bdev)); nr_pages = min(nr_pages, BIO_MAX_PAGES); BUG_ON(nr_pages <= 0); - dio_bio_alloc(dio, sdio, dio->map_bh.b_bdev, sector, nr_pages); + dio_bio_alloc(dio, sdio, map_bh->b_bdev, sector, nr_pages); sdio->boundary = 0; out: return ret; @@ -686,7 +689,8 @@ static int dio_bio_add_page(struct dio_submit *sdio) * The caller of this function is responsible for removing cur_page from the * dio, and for dropping the refcount which came from that presence. */ -static int dio_send_cur_page(struct dio *dio, struct dio_submit *sdio) +static int dio_send_cur_page(struct dio *dio, struct dio_submit *sdio, + struct buffer_head *map_bh) { int ret = 0; @@ -721,14 +725,14 @@ static int dio_send_cur_page(struct dio *dio, struct dio_submit *sdio) } if (sdio->bio == NULL) { - ret = dio_new_bio(dio, sdio, sdio->cur_page_block); + ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh); if (ret) goto out; } if (dio_bio_add_page(sdio) != 0) { dio_bio_submit(dio, sdio); - ret = dio_new_bio(dio, sdio, sdio->cur_page_block); + ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh); if (ret == 0) { ret = dio_bio_add_page(sdio); BUG_ON(ret != 0); @@ -757,7 +761,8 @@ out: */ static int submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page, - unsigned offset, unsigned len, sector_t blocknr) + unsigned offset, unsigned len, sector_t blocknr, + struct buffer_head *map_bh) { int ret = 0; @@ -782,7 +787,7 @@ submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page, * avoid metadata seeks. */ if (sdio->boundary) { - ret = dio_send_cur_page(dio, sdio); + ret = dio_send_cur_page(dio, sdio, map_bh); page_cache_release(sdio->cur_page); sdio->cur_page = NULL; } @@ -793,7 +798,7 @@ submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page, * If there's a deferred page already there then send it. */ if (sdio->cur_page) { - ret = dio_send_cur_page(dio, sdio); + ret = dio_send_cur_page(dio, sdio, map_bh); page_cache_release(sdio->cur_page); sdio->cur_page = NULL; if (ret) @@ -815,16 +820,16 @@ out: * file blocks. Only called for S_ISREG files - blockdevs do not set * buffer_new */ -static void clean_blockdev_aliases(struct dio *dio) +static void clean_blockdev_aliases(struct dio *dio, struct buffer_head *map_bh) { unsigned i; unsigned nblocks; - nblocks = dio->map_bh.b_size >> dio->inode->i_blkbits; + nblocks = map_bh->b_size >> dio->inode->i_blkbits; for (i = 0; i < nblocks; i++) { - unmap_underlying_metadata(dio->map_bh.b_bdev, - dio->map_bh.b_blocknr + i); + unmap_underlying_metadata(map_bh->b_bdev, + map_bh->b_blocknr + i); } } @@ -837,7 +842,8 @@ static void clean_blockdev_aliases(struct dio *dio) * `end' is zero if we're doing the start of the IO, 1 at the end of the * IO. */ -static void dio_zero_block(struct dio *dio, struct dio_submit *sdio, int end) +static void dio_zero_block(struct dio *dio, struct dio_submit *sdio, int end, + struct buffer_head *map_bh) { unsigned dio_blocks_per_fs_block; unsigned this_chunk_blocks; /* In dio_blocks */ @@ -845,7 +851,7 @@ static void dio_zero_block(struct dio *dio, struct dio_submit *sdio, int end) struct page *page; sdio->start_zero_done = 1; - if (!sdio->blkfactor || !buffer_new(&dio->map_bh)) + if (!sdio->blkfactor || !buffer_new(map_bh)) return; dio_blocks_per_fs_block = 1 << sdio->blkfactor; @@ -865,7 +871,7 @@ static void dio_zero_block(struct dio *dio, struct dio_submit *sdio, int end) page = ZERO_PAGE(0); if (submit_page_section(dio, sdio, page, 0, this_chunk_bytes, - sdio->next_block_for_io)) + sdio->next_block_for_io, map_bh)) return; sdio->next_block_for_io += this_chunk_blocks; @@ -887,13 +893,13 @@ static void dio_zero_block(struct dio *dio, struct dio_submit *sdio, int end) * it should set b_size to PAGE_SIZE or more inside get_block(). This gives * fine alignment but still allows this function to work in PAGE_SIZE units. */ -static int do_direct_IO(struct dio *dio, struct dio_submit *sdio) +static int do_direct_IO(struct dio *dio, struct dio_submit *sdio, + struct buffer_head *map_bh) { const unsigned blkbits = sdio->blkbits; const unsigned blocks_per_page = PAGE_SIZE >> blkbits; struct page *page; unsigned block_in_page; - struct buffer_head *map_bh = &dio->map_bh; int ret = 0; /* The I/O can start at any block offset within the first page */ @@ -919,7 +925,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio) unsigned long blkmask; unsigned long dio_remainder; - ret = get_more_blocks(dio, sdio); + ret = get_more_blocks(dio, sdio, map_bh); if (ret) { page_cache_release(page); goto out; @@ -932,7 +938,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio) sdio->next_block_for_io = map_bh->b_blocknr << sdio->blkfactor; if (buffer_new(map_bh)) - clean_blockdev_aliases(dio); + clean_blockdev_aliases(dio, map_bh); if (!sdio->blkfactor) goto do_holes; @@ -991,7 +997,7 @@ do_holes: * we must zero out the start of this block. */ if (unlikely(sdio->blkfactor && !sdio->start_zero_done)) - dio_zero_block(dio, sdio, 0); + dio_zero_block(dio, sdio, 0, map_bh); /* * Work out, in this_chunk_blocks, how much disk we @@ -1011,7 +1017,8 @@ do_holes: ret = submit_page_section(dio, sdio, page, offset_in_page, this_chunk_bytes, - sdio->next_block_for_io); + sdio->next_block_for_io, + map_bh); if (ret) { page_cache_release(page); goto out; @@ -1047,6 +1054,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, ssize_t ret = 0; ssize_t ret2; size_t bytes; + struct buffer_head map_bh = { 0, }; dio->inode = inode; dio->rw = rw; @@ -1101,7 +1109,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, sdio->total_pages += (bytes + PAGE_SIZE - 1) / PAGE_SIZE; sdio->curr_user_address = user_addr; - ret = do_direct_IO(dio, sdio); + ret = do_direct_IO(dio, sdio, &map_bh); dio->result += iov[seg].iov_len - ((sdio->final_block_in_request - sdio->block_in_file) << @@ -1124,10 +1132,10 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, * There may be some unwritten disk at the end of a part-written * fs-block-sized block. Go zero that now. */ - dio_zero_block(dio, sdio, 1); + dio_zero_block(dio, sdio, 1, &map_bh); if (sdio->cur_page) { - ret2 = dio_send_cur_page(dio, sdio); + ret2 = dio_send_cur_page(dio, sdio, &map_bh); if (ret == 0) ret = ret2; page_cache_release(sdio->cur_page); -- cgit v1.2.3