diff options
Diffstat (limited to 'fs/direct-io.c')
| -rw-r--r-- | fs/direct-io.c | 646 |
1 files changed, 337 insertions, 309 deletions
diff --git a/fs/direct-io.c b/fs/direct-io.c index 44a360ca8046..d740ab67ff6e 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -39,7 +39,7 @@ /* * How many user pages to map in one call to get_user_pages(). This determines - * the size of a structure on the stack. + * the size of a structure in the slab cache */ #define DIO_PAGES 64 @@ -55,13 +55,10 @@ * blocksize. */ -struct dio { - /* BIO submission state */ +/* dio_state only used in the submission path */ + +struct dio_submit { struct bio *bio; /* bio under assembly */ - struct inode *inode; - int rw; - loff_t i_size; /* i_size when submitted */ - int flags; /* doesn't change */ unsigned blkbits; /* doesn't change */ unsigned blkfactor; /* When we're using an alignment which is finer than the filesystem's soft @@ -76,18 +73,17 @@ struct dio { sector_t block_in_file; /* Current offset into the underlying file in dio_block units. */ unsigned blocks_available; /* At block_in_file. changes */ + int reap_counter; /* rate limit reaping */ sector_t final_block_in_request;/* doesn't change */ unsigned first_block_in_page; /* doesn't change, Used only once */ int boundary; /* prev block is at a boundary */ - int reap_counter; /* rate limit reaping */ get_block_t *get_block; /* block mapping function */ - dio_iodone_t *end_io; /* IO completion function */ dio_submit_t *submit_io; /* IO submition function */ + loff_t logical_offset_in_bio; /* current first logical block in bio */ sector_t final_block_in_bio; /* current final block in bio + 1 */ sector_t next_block_for_io; /* next block to be put under IO, in dio_blocks units */ - struct buffer_head map_bh; /* last get_block() result */ /* * Deferred addition of a page to the dio. These variables are @@ -100,18 +96,6 @@ struct dio { sector_t cur_page_block; /* Where it starts */ loff_t cur_page_fs_offset; /* Offset in file */ - /* BIO completion state */ - spinlock_t bio_lock; /* protects BIO fields below */ - unsigned long refcount; /* direct_io_worker() and bios */ - struct bio *bio_list; /* singly linked via bi_private */ - struct task_struct *waiter; /* waiting task (NULL if none) */ - - /* AIO related stuff */ - struct kiocb *iocb; /* kiocb */ - int is_async; /* is IO async ? */ - int io_error; /* IO error in completion path */ - ssize_t result; /* IO result */ - /* * Page fetching state. These variables belong to dio_refill_pages(). */ @@ -125,7 +109,30 @@ struct dio { */ unsigned head; /* next page to process */ unsigned tail; /* last valid page + 1 */ +}; + +/* dio_state communicated between submission path and end_io */ +struct dio { + int flags; /* doesn't change */ + int rw; + struct inode *inode; + 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 */ int page_errors; /* errno from get_user_pages() */ + int is_async; /* is IO async ? */ + int io_error; /* IO error in completion path */ + unsigned long refcount; /* direct_io_worker() and bios */ + struct bio *bio_list; /* singly linked via bi_private */ + struct task_struct *waiter; /* waiting task (NULL if none) */ + + /* AIO related stuff */ + struct kiocb *iocb; /* kiocb */ + ssize_t result; /* IO result */ /* * pages[] (and any fields placed after it) are not zeroed out at @@ -133,7 +140,9 @@ struct dio { * wish that they not be zeroed. */ struct page *pages[DIO_PAGES]; /* page buffer */ -}; +} ____cacheline_aligned_in_smp; + +static struct kmem_cache *dio_cache __read_mostly; static void __inode_dio_wait(struct inode *inode) { @@ -182,27 +191,27 @@ EXPORT_SYMBOL_GPL(inode_dio_done); /* * How many pages are in the queue? */ -static inline unsigned dio_pages_present(struct dio *dio) +static inline unsigned dio_pages_present(struct dio_submit *sdio) { - return dio->tail - dio->head; + return sdio->tail - sdio->head; } /* * Go grab and pin some userspace pages. Typically we'll get 64 at a time. */ -static int dio_refill_pages(struct dio *dio) +static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio) { int ret; int nr_pages; - nr_pages = min(dio->total_pages - dio->curr_page, DIO_PAGES); + nr_pages = min(sdio->total_pages - sdio->curr_page, DIO_PAGES); ret = get_user_pages_fast( - dio->curr_user_address, /* Where from? */ + sdio->curr_user_address, /* Where from? */ nr_pages, /* How many pages? */ dio->rw == READ, /* Write to memory? */ &dio->pages[0]); /* Put results here */ - if (ret < 0 && dio->blocks_available && (dio->rw & WRITE)) { + if (ret < 0 && sdio->blocks_available && (dio->rw & WRITE)) { struct page *page = ZERO_PAGE(0); /* * A memory fault, but the filesystem has some outstanding @@ -213,17 +222,17 @@ static int dio_refill_pages(struct dio *dio) dio->page_errors = ret; page_cache_get(page); dio->pages[0] = page; - dio->head = 0; - dio->tail = 1; + sdio->head = 0; + sdio->tail = 1; ret = 0; goto out; } if (ret >= 0) { - dio->curr_user_address += ret * PAGE_SIZE; - dio->curr_page += ret; - dio->head = 0; - dio->tail = ret; + sdio->curr_user_address += ret * PAGE_SIZE; + sdio->curr_page += ret; + sdio->head = 0; + sdio->tail = ret; ret = 0; } out: @@ -236,17 +245,18 @@ out: * decent number of pages, less frequently. To provide nicer use of the * L1 cache. */ -static struct page *dio_get_page(struct dio *dio) +static inline struct page *dio_get_page(struct dio *dio, + struct dio_submit *sdio) { - if (dio_pages_present(dio) == 0) { + if (dio_pages_present(sdio) == 0) { int ret; - ret = dio_refill_pages(dio); + ret = dio_refill_pages(dio, sdio); if (ret) return ERR_PTR(ret); - BUG_ON(dio_pages_present(dio) == 0); + BUG_ON(dio_pages_present(sdio) == 0); } - return dio->pages[dio->head++]; + return dio->pages[sdio->head++]; } /** @@ -292,7 +302,7 @@ 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); @@ -323,7 +333,7 @@ static void dio_bio_end_aio(struct bio *bio, int error) if (remaining == 0) { dio_complete(dio, dio->iocb->ki_pos, 0, true); - kfree(dio); + kmem_cache_free(dio_cache, dio); } } @@ -367,9 +377,10 @@ void dio_end_io(struct bio *bio, int error) } EXPORT_SYMBOL_GPL(dio_end_io); -static void -dio_bio_alloc(struct dio *dio, struct block_device *bdev, - sector_t first_sector, int nr_vecs) +static inline void +dio_bio_alloc(struct dio *dio, struct dio_submit *sdio, + struct block_device *bdev, + sector_t first_sector, int nr_vecs) { struct bio *bio; @@ -386,8 +397,8 @@ dio_bio_alloc(struct dio *dio, struct block_device *bdev, else bio->bi_end_io = dio_bio_end_io; - dio->bio = bio; - dio->logical_offset_in_bio = dio->cur_page_fs_offset; + sdio->bio = bio; + sdio->logical_offset_in_bio = sdio->cur_page_fs_offset; } /* @@ -397,9 +408,9 @@ dio_bio_alloc(struct dio *dio, struct block_device *bdev, * * bios hold a dio reference between submit_bio and ->end_io. */ -static void dio_bio_submit(struct dio *dio) +static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio) { - struct bio *bio = dio->bio; + struct bio *bio = sdio->bio; unsigned long flags; bio->bi_private = dio; @@ -411,24 +422,24 @@ static void dio_bio_submit(struct dio *dio) if (dio->is_async && dio->rw == READ) bio_set_pages_dirty(bio); - if (dio->submit_io) - dio->submit_io(dio->rw, bio, dio->inode, - dio->logical_offset_in_bio); + if (sdio->submit_io) + sdio->submit_io(dio->rw, bio, dio->inode, + sdio->logical_offset_in_bio); else submit_bio(dio->rw, bio); - dio->bio = NULL; - dio->boundary = 0; - dio->logical_offset_in_bio = 0; + sdio->bio = NULL; + sdio->boundary = 0; + sdio->logical_offset_in_bio = 0; } /* * Release any resources in case of a failure */ -static void dio_cleanup(struct dio *dio) +static inline void dio_cleanup(struct dio *dio, struct dio_submit *sdio) { - while (dio_pages_present(dio)) - page_cache_release(dio_get_page(dio)); + while (dio_pages_present(sdio)) + page_cache_release(dio_get_page(dio, sdio)); } /* @@ -518,11 +529,11 @@ static void dio_await_completion(struct dio *dio) * * This also helps to limit the peak amount of pinned userspace memory. */ -static int dio_bio_reap(struct dio *dio) +static inline int dio_bio_reap(struct dio *dio, struct dio_submit *sdio) { int ret = 0; - if (dio->reap_counter++ >= 64) { + if (sdio->reap_counter++ >= 64) { while (dio->bio_list) { unsigned long flags; struct bio *bio; @@ -536,14 +547,14 @@ static int dio_bio_reap(struct dio *dio) if (ret == 0) ret = ret2; } - dio->reap_counter = 0; + sdio->reap_counter = 0; } return ret; } /* * Call into the fs to map some more disk blocks. We record the current number - * of available blocks at dio->blocks_available. These are in units of the + * of available blocks at sdio->blocks_available. These are in units of the * fs blocksize, (1 << inode->i_blkbits). * * The fs is allowed to map lots of blocks at once. If it wants to do that, @@ -564,10 +575,10 @@ static int dio_bio_reap(struct dio *dio) * 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) +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 */ @@ -580,11 +591,11 @@ static int get_more_blocks(struct dio *dio) */ ret = dio->page_errors; if (ret == 0) { - BUG_ON(dio->block_in_file >= dio->final_block_in_request); - fs_startblk = dio->block_in_file >> dio->blkfactor; - dio_count = dio->final_block_in_request - dio->block_in_file; - fs_count = dio_count >> dio->blkfactor; - blkmask = (1 << dio->blkfactor) - 1; + BUG_ON(sdio->block_in_file >= sdio->final_block_in_request); + fs_startblk = sdio->block_in_file >> sdio->blkfactor; + dio_count = sdio->final_block_in_request - sdio->block_in_file; + fs_count = dio_count >> sdio->blkfactor; + blkmask = (1 << sdio->blkfactor) - 1; if (dio_count & blkmask) fs_count++; @@ -604,13 +615,16 @@ static int get_more_blocks(struct dio *dio) */ create = dio->rw & WRITE; if (dio->flags & DIO_SKIP_HOLES) { - if (dio->block_in_file < (i_size_read(dio->inode) >> - dio->blkbits)) + if (sdio->block_in_file < (i_size_read(dio->inode) >> + sdio->blkbits)) create = 0; } - ret = (*dio->get_block)(dio->inode, fs_startblk, + ret = (*sdio->get_block)(dio->inode, fs_startblk, map_bh, create); + + /* Store for completion */ + dio->private = map_bh->b_private; } return ret; } @@ -618,20 +632,21 @@ static int get_more_blocks(struct dio *dio) /* * There is no bio. Make one now. */ -static int dio_new_bio(struct dio *dio, sector_t start_sector) +static inline int dio_new_bio(struct dio *dio, struct dio_submit *sdio, + sector_t start_sector, struct buffer_head *map_bh) { sector_t sector; int ret, nr_pages; - ret = dio_bio_reap(dio); + ret = dio_bio_reap(dio, sdio); if (ret) goto out; - sector = start_sector << (dio->blkbits - 9); - nr_pages = min(dio->pages_in_io, bio_get_nr_vecs(dio->map_bh.b_bdev)); + sector = start_sector << (sdio->blkbits - 9); + 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, dio->map_bh.b_bdev, sector, nr_pages); - dio->boundary = 0; + dio_bio_alloc(dio, sdio, map_bh->b_bdev, sector, nr_pages); + sdio->boundary = 0; out: return ret; } @@ -643,21 +658,21 @@ out: * * Return zero on success. Non-zero means the caller needs to start a new BIO. */ -static int dio_bio_add_page(struct dio *dio) +static inline int dio_bio_add_page(struct dio_submit *sdio) { int ret; - ret = bio_add_page(dio->bio, dio->cur_page, - dio->cur_page_len, dio->cur_page_offset); - if (ret == dio->cur_page_len) { + ret = bio_add_page(sdio->bio, sdio->cur_page, + sdio->cur_page_len, sdio->cur_page_offset); + if (ret == sdio->cur_page_len) { /* * Decrement count only, if we are done with this page */ - if ((dio->cur_page_len + dio->cur_page_offset) == PAGE_SIZE) - dio->pages_in_io--; - page_cache_get(dio->cur_page); - dio->final_block_in_bio = dio->cur_page_block + - (dio->cur_page_len >> dio->blkbits); + if ((sdio->cur_page_len + sdio->cur_page_offset) == PAGE_SIZE) + sdio->pages_in_io--; + page_cache_get(sdio->cur_page); + sdio->final_block_in_bio = sdio->cur_page_block + + (sdio->cur_page_len >> sdio->blkbits); ret = 0; } else { ret = 1; @@ -675,14 +690,15 @@ static int dio_bio_add_page(struct dio *dio) * 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) +static inline int dio_send_cur_page(struct dio *dio, struct dio_submit *sdio, + struct buffer_head *map_bh) { int ret = 0; - if (dio->bio) { - loff_t cur_offset = dio->cur_page_fs_offset; - loff_t bio_next_offset = dio->logical_offset_in_bio + - dio->bio->bi_size; + if (sdio->bio) { + loff_t cur_offset = sdio->cur_page_fs_offset; + loff_t bio_next_offset = sdio->logical_offset_in_bio + + sdio->bio->bi_size; /* * See whether this new request is contiguous with the old. @@ -698,28 +714,28 @@ static int dio_send_cur_page(struct dio *dio) * be the next logical offset in the bio, submit the bio we * have. */ - if (dio->final_block_in_bio != dio->cur_page_block || + if (sdio->final_block_in_bio != sdio->cur_page_block || cur_offset != bio_next_offset) - dio_bio_submit(dio); + dio_bio_submit(dio, sdio); /* * Submit now if the underlying fs is about to perform a * metadata read */ - else if (dio->boundary) - dio_bio_submit(dio); + else if (sdio->boundary) + dio_bio_submit(dio, sdio); } - if (dio->bio == NULL) { - ret = dio_new_bio(dio, dio->cur_page_block); + if (sdio->bio == NULL) { + ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh); if (ret) goto out; } - if (dio_bio_add_page(dio) != 0) { - dio_bio_submit(dio); - ret = dio_new_bio(dio, dio->cur_page_block); + if (dio_bio_add_page(sdio) != 0) { + dio_bio_submit(dio, sdio); + ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh); if (ret == 0) { - ret = dio_bio_add_page(dio); + ret = dio_bio_add_page(sdio); BUG_ON(ret != 0); } } @@ -744,9 +760,10 @@ out: * If that doesn't work out then we put the old page into the bio and add this * page to the dio instead. */ -static int -submit_page_section(struct dio *dio, struct page *page, - unsigned offset, unsigned len, sector_t blocknr) +static inline int +submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page, + unsigned offset, unsigned len, sector_t blocknr, + struct buffer_head *map_bh) { int ret = 0; @@ -760,20 +777,20 @@ submit_page_section(struct dio *dio, struct page *page, /* * Can we just grow the current page's presence in the dio? */ - if ( (dio->cur_page == page) && - (dio->cur_page_offset + dio->cur_page_len == offset) && - (dio->cur_page_block + - (dio->cur_page_len >> dio->blkbits) == blocknr)) { - dio->cur_page_len += len; + if (sdio->cur_page == page && + sdio->cur_page_offset + sdio->cur_page_len == offset && + sdio->cur_page_block + + (sdio->cur_page_len >> sdio->blkbits) == blocknr) { + sdio->cur_page_len += len; /* - * If dio->boundary then we want to schedule the IO now to + * If sdio->boundary then we want to schedule the IO now to * avoid metadata seeks. */ - if (dio->boundary) { - ret = dio_send_cur_page(dio); - page_cache_release(dio->cur_page); - dio->cur_page = NULL; + if (sdio->boundary) { + ret = dio_send_cur_page(dio, sdio, map_bh); + page_cache_release(sdio->cur_page); + sdio->cur_page = NULL; } goto out; } @@ -781,20 +798,20 @@ submit_page_section(struct dio *dio, struct page *page, /* * If there's a deferred page already there then send it. */ - if (dio->cur_page) { - ret = dio_send_cur_page(dio); - page_cache_release(dio->cur_page); - dio->cur_page = NULL; + if (sdio->cur_page) { + ret = dio_send_cur_page(dio, sdio, map_bh); + page_cache_release(sdio->cur_page); + sdio->cur_page = NULL; if (ret) goto out; } page_cache_get(page); /* It is in dio */ - dio->cur_page = page; - dio->cur_page_offset = offset; - dio->cur_page_len = len; - dio->cur_page_block = blocknr; - dio->cur_page_fs_offset = dio->block_in_file << dio->blkbits; + sdio->cur_page = page; + sdio->cur_page_offset = offset; + sdio->cur_page_len = len; + sdio->cur_page_block = blocknr; + sdio->cur_page_fs_offset = sdio->block_in_file << sdio->blkbits; out: return ret; } @@ -804,16 +821,16 @@ 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); } } @@ -826,19 +843,20 @@ 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, int end) +static inline 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 */ unsigned this_chunk_bytes; struct page *page; - dio->start_zero_done = 1; - if (!dio->blkfactor || !buffer_new(&dio->map_bh)) + sdio->start_zero_done = 1; + if (!sdio->blkfactor || !buffer_new(map_bh)) return; - dio_blocks_per_fs_block = 1 << dio->blkfactor; - this_chunk_blocks = dio->block_in_file & (dio_blocks_per_fs_block - 1); + dio_blocks_per_fs_block = 1 << sdio->blkfactor; + this_chunk_blocks = sdio->block_in_file & (dio_blocks_per_fs_block - 1); if (!this_chunk_blocks) return; @@ -850,14 +868,14 @@ static void dio_zero_block(struct dio *dio, int end) if (end) this_chunk_blocks = dio_blocks_per_fs_block - this_chunk_blocks; - this_chunk_bytes = this_chunk_blocks << dio->blkbits; + this_chunk_bytes = this_chunk_blocks << sdio->blkbits; page = ZERO_PAGE(0); - if (submit_page_section(dio, page, 0, this_chunk_bytes, - dio->next_block_for_io)) + if (submit_page_section(dio, sdio, page, 0, this_chunk_bytes, + sdio->next_block_for_io, map_bh)) return; - dio->next_block_for_io += this_chunk_blocks; + sdio->next_block_for_io += this_chunk_blocks; } /* @@ -876,20 +894,20 @@ static void dio_zero_block(struct dio *dio, 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) +static int do_direct_IO(struct dio *dio, struct dio_submit *sdio, + struct buffer_head *map_bh) { - const unsigned blkbits = dio->blkbits; + 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 */ - block_in_page = dio->first_block_in_page; + block_in_page = sdio->first_block_in_page; - while (dio->block_in_file < dio->final_block_in_request) { - page = dio_get_page(dio); + while (sdio->block_in_file < sdio->final_block_in_request) { + page = dio_get_page(dio, sdio); if (IS_ERR(page)) { ret = PTR_ERR(page); goto out; @@ -901,14 +919,14 @@ static int do_direct_IO(struct dio *dio) unsigned this_chunk_blocks; /* # of blocks */ unsigned u; - if (dio->blocks_available == 0) { + if (sdio->blocks_available == 0) { /* * Need to go and map some more disk */ unsigned long blkmask; unsigned long dio_remainder; - ret = get_more_blocks(dio); + ret = get_more_blocks(dio, sdio, map_bh); if (ret) { page_cache_release(page); goto out; @@ -916,18 +934,18 @@ static int do_direct_IO(struct dio *dio) if (!buffer_mapped(map_bh)) goto do_holes; - dio->blocks_available = - map_bh->b_size >> dio->blkbits; - dio->next_block_for_io = - map_bh->b_blocknr << dio->blkfactor; + sdio->blocks_available = + map_bh->b_size >> sdio->blkbits; + 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 (!dio->blkfactor) + if (!sdio->blkfactor) goto do_holes; - blkmask = (1 << dio->blkfactor) - 1; - dio_remainder = (dio->block_in_file & blkmask); + blkmask = (1 << sdio->blkfactor) - 1; + dio_remainder = (sdio->block_in_file & blkmask); /* * If we are at the start of IO and that IO @@ -941,8 +959,8 @@ static int do_direct_IO(struct dio *dio) * on-disk */ if (!buffer_new(map_bh)) - dio->next_block_for_io += dio_remainder; - dio->blocks_available -= dio_remainder; + sdio->next_block_for_io += dio_remainder; + sdio->blocks_available -= dio_remainder; } do_holes: /* Handle holes */ @@ -961,7 +979,7 @@ do_holes: */ i_size_aligned = ALIGN(i_size_read(dio->inode), 1 << blkbits); - if (dio->block_in_file >= + if (sdio->block_in_file >= i_size_aligned >> blkbits) { /* We hit eof */ page_cache_release(page); @@ -969,7 +987,7 @@ do_holes: } zero_user(page, block_in_page << blkbits, 1 << blkbits); - dio->block_in_file++; + sdio->block_in_file++; block_in_page++; goto next_block; } @@ -979,38 +997,41 @@ do_holes: * is finer than the underlying fs, go check to see if * we must zero out the start of this block. */ - if (unlikely(dio->blkfactor && !dio->start_zero_done)) - dio_zero_block(dio, 0); + if (unlikely(sdio->blkfactor && !sdio->start_zero_done)) + dio_zero_block(dio, sdio, 0, map_bh); /* * Work out, in this_chunk_blocks, how much disk we * can add to this page */ - this_chunk_blocks = dio->blocks_available; + this_chunk_blocks = sdio->blocks_available; u = (PAGE_SIZE - offset_in_page) >> blkbits; if (this_chunk_blocks > u) this_chunk_blocks = u; - u = dio->final_block_in_request - dio->block_in_file; + u = sdio->final_block_in_request - sdio->block_in_file; if (this_chunk_blocks > u) this_chunk_blocks = u; this_chunk_bytes = this_chunk_blocks << blkbits; BUG_ON(this_chunk_bytes == 0); - dio->boundary = buffer_boundary(map_bh); - ret = submit_page_section(dio, page, offset_in_page, - this_chunk_bytes, dio->next_block_for_io); + sdio->boundary = buffer_boundary(map_bh); + ret = submit_page_section(dio, sdio, page, + offset_in_page, + this_chunk_bytes, + sdio->next_block_for_io, + map_bh); if (ret) { page_cache_release(page); goto out; } - dio->next_block_for_io += this_chunk_blocks; + sdio->next_block_for_io += this_chunk_blocks; - dio->block_in_file += this_chunk_blocks; + sdio->block_in_file += this_chunk_blocks; block_in_page += this_chunk_blocks; - dio->blocks_available -= this_chunk_blocks; + sdio->blocks_available -= this_chunk_blocks; next_block: - BUG_ON(dio->block_in_file > dio->final_block_in_request); - if (dio->block_in_file == dio->final_block_in_request) + BUG_ON(sdio->block_in_file > sdio->final_block_in_request); + if (sdio->block_in_file == sdio->final_block_in_request) break; } @@ -1022,135 +1043,10 @@ out: return ret; } -static ssize_t -direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, - const struct iovec *iov, loff_t offset, unsigned long nr_segs, - unsigned blkbits, get_block_t get_block, dio_iodone_t end_io, - dio_submit_t submit_io, struct dio *dio) +static inline int drop_refcount(struct dio *dio) { - unsigned long user_addr; + int ret2; unsigned long flags; - int seg; - ssize_t ret = 0; - ssize_t ret2; - size_t bytes; - - dio->inode = inode; - dio->rw = rw; - dio->blkbits = blkbits; - dio->blkfactor = inode->i_blkbits - blkbits; - dio->block_in_file = offset >> blkbits; - - dio->get_block = get_block; - dio->end_io = end_io; - dio->submit_io = submit_io; - dio->final_block_in_bio = -1; - dio->next_block_for_io = -1; - - dio->iocb = iocb; - dio->i_size = i_size_read(inode); - - spin_lock_init(&dio->bio_lock); - dio->refcount = 1; - - /* - * In case of non-aligned buffers, we may need 2 more - * pages since we need to zero out first and last block. - */ - if (unlikely(dio->blkfactor)) - dio->pages_in_io = 2; - - for (seg = 0; seg < nr_segs; seg++) { - user_addr = (unsigned long)iov[seg].iov_base; - dio->pages_in_io += - ((user_addr+iov[seg].iov_len +PAGE_SIZE-1)/PAGE_SIZE - - user_addr/PAGE_SIZE); - } - - for (seg = 0; seg < nr_segs; seg++) { - user_addr = (unsigned long)iov[seg].iov_base; - dio->size += bytes = iov[seg].iov_len; - - /* Index into the first page of the first block */ - dio->first_block_in_page = (user_addr & ~PAGE_MASK) >> blkbits; - dio->final_block_in_request = dio->block_in_file + - (bytes >> blkbits); - /* Page fetching state */ - dio->head = 0; - dio->tail = 0; - dio->curr_page = 0; - - dio->total_pages = 0; - if (user_addr & (PAGE_SIZE-1)) { - dio->total_pages++; - bytes -= PAGE_SIZE - (user_addr & (PAGE_SIZE - 1)); - } - dio->total_pages += (bytes + PAGE_SIZE - 1) / PAGE_SIZE; - dio->curr_user_address = user_addr; - - ret = do_direct_IO(dio); - - dio->result += iov[seg].iov_len - - ((dio->final_block_in_request - dio->block_in_file) << - blkbits); - - if (ret) { - dio_cleanup(dio); - break; - } - } /* end iovec loop */ - - if (ret == -ENOTBLK) { - /* - * The remaining part of the request will be - * be handled by buffered I/O when we return - */ - ret = 0; - } - /* - * 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, 1); - - if (dio->cur_page) { - ret2 = dio_send_cur_page(dio); - if (ret == 0) - ret = ret2; - page_cache_release(dio->cur_page); - dio->cur_page = NULL; - } - if (dio->bio) - dio_bio_submit(dio); - - /* - * It is possible that, we return short IO due to end of file. - * In that case, we need to release all the pages we got hold on. - */ - dio_cleanup(dio); - - /* - * All block lookups have been performed. For READ requests - * we can let i_mutex go now that its achieved its purpose - * of protecting us from looking up uninitialized blocks. - */ - if (rw == READ && (dio->flags & DIO_LOCKING)) - mutex_unlock(&dio->inode->i_mutex); - - /* - * The only time we want to leave bios in flight is when a successful - * partial aio read or full aio write have been setup. In that case - * bio completion will call aio_complete. The only time it's safe to - * call aio_complete is when we return -EIOCBQUEUED, so we key on that. - * This had *better* be the only place that raises -EIOCBQUEUED. - */ - BUG_ON(ret == -EIOCBQUEUED); - if (dio->is_async && ret == 0 && dio->result && - ((rw & READ) || (dio->result == dio->size))) - ret = -EIOCBQUEUED; - - if (ret != -EIOCBQUEUED) - dio_await_completion(dio); /* * Sync will always be dropping the final ref and completing the @@ -1166,14 +1062,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, spin_lock_irqsave(&dio->bio_lock, flags); ret2 = --dio->refcount; spin_unlock_irqrestore(&dio->bio_lock, flags); - - if (ret2 == 0) { - ret = dio_complete(dio, offset, ret, false); - kfree(dio); - } else - BUG_ON(ret != -EIOCBQUEUED); - - return ret; + return ret2; } /* @@ -1195,6 +1084,11 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, * expected that filesystem provide exclusion between new direct I/O * and truncates. For DIO_LOCKING filesystems this is done by i_mutex, * but other filesystems need to take care of this on their own. + * + * NOTE: if you pass "sdio" to anything by pointer make sure that function + * is always inlined. Otherwise gcc is unable to split the structure into + * individual fields and will generate much worse code. This is important + * for the whole file. */ ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, @@ -1211,6 +1105,10 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, ssize_t retval = -EINVAL; loff_t end = offset; struct dio *dio; + struct dio_submit sdio = { 0, }; + unsigned long user_addr; + size_t bytes; + struct buffer_head map_bh = { 0, }; if (rw & WRITE) rw = WRITE_ODIRECT; @@ -1244,7 +1142,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, if (rw == READ && end == offset) return 0; - dio = kmalloc(sizeof(*dio), GFP_KERNEL); + dio = kmem_cache_alloc(dio_cache, GFP_KERNEL); retval = -ENOMEM; if (!dio) goto out; @@ -1268,7 +1166,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, end - 1); if (retval) { mutex_unlock(&inode->i_mutex); - kfree(dio); + kmem_cache_free(dio_cache, dio); goto out; } } @@ -1288,11 +1186,141 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) && (end > i_size_read(inode))); - retval = direct_io_worker(rw, iocb, inode, iov, offset, - nr_segs, blkbits, get_block, end_io, - submit_io, dio); + retval = 0; + + dio->inode = inode; + dio->rw = rw; + sdio.blkbits = blkbits; + sdio.blkfactor = inode->i_blkbits - blkbits; + sdio.block_in_file = offset >> blkbits; + + sdio.get_block = get_block; + dio->end_io = end_io; + sdio.submit_io = submit_io; + sdio.final_block_in_bio = -1; + sdio.next_block_for_io = -1; + + dio->iocb = iocb; + dio->i_size = i_size_read(inode); + + spin_lock_init(&dio->bio_lock); + dio->refcount = 1; + + /* + * In case of non-aligned buffers, we may need 2 more + * pages since we need to zero out first and last block. + */ + if (unlikely(sdio.blkfactor)) + sdio.pages_in_io = 2; + + for (seg = 0; seg < nr_segs; seg++) { + user_addr = (unsigned long)iov[seg].iov_base; + sdio.pages_in_io += + ((user_addr + iov[seg].iov_len + PAGE_SIZE-1) / + PAGE_SIZE - user_addr / PAGE_SIZE); + } + + for (seg = 0; seg < nr_segs; seg++) { + user_addr = (unsigned long)iov[seg].iov_base; + sdio.size += bytes = iov[seg].iov_len; + + /* Index into the first page of the first block */ + sdio.first_block_in_page = (user_addr & ~PAGE_MASK) >> blkbits; + sdio.final_block_in_request = sdio.block_in_file + + (bytes >> blkbits); + /* Page fetching state */ + sdio.head = 0; + sdio.tail = 0; + sdio.curr_page = 0; + + sdio.total_pages = 0; + if (user_addr & (PAGE_SIZE-1)) { + sdio.total_pages++; + bytes -= PAGE_SIZE - (user_addr & (PAGE_SIZE - 1)); + } + sdio.total_pages += (bytes + PAGE_SIZE - 1) / PAGE_SIZE; + sdio.curr_user_address = user_addr; + + retval = do_direct_IO(dio, &sdio, &map_bh); + + dio->result += iov[seg].iov_len - + ((sdio.final_block_in_request - sdio.block_in_file) << + blkbits); + + if (retval) { + dio_cleanup(dio, &sdio); + break; + } + } /* end iovec loop */ + + if (retval == -ENOTBLK) { + /* + * The remaining part of the request will be + * be handled by buffered I/O when we return + */ + retval = 0; + } + /* + * 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, &map_bh); + + if (sdio.cur_page) { + ssize_t ret2; + + ret2 = dio_send_cur_page(dio, &sdio, &map_bh); + if (retval == 0) + retval = ret2; + page_cache_release(sdio.cur_page); + sdio.cur_page = NULL; + } + if (sdio.bio) + dio_bio_submit(dio, &sdio); + + /* + * It is possible that, we return short IO due to end of file. + * In that case, we need to release all the pages we got hold on. + */ + dio_cleanup(dio, &sdio); + + /* + * All block lookups have been performed. For READ requests + * we can let i_mutex go now that its achieved its purpose + * of protecting us from looking up uninitialized blocks. + */ + if (rw == READ && (dio->flags & DIO_LOCKING)) + mutex_unlock(&dio->inode->i_mutex); + + /* + * The only time we want to leave bios in flight is when a successful + * partial aio read or full aio write have been setup. In that case + * bio completion will call aio_complete. The only time it's safe to + * call aio_complete is when we return -EIOCBQUEUED, so we key on that. + * This had *better* be the only place that raises -EIOCBQUEUED. + */ + BUG_ON(retval == -EIOCBQUEUED); + if (dio->is_async && retval == 0 && dio->result && + ((rw & READ) || (dio->result == sdio.size))) + retval = -EIOCBQUEUED; + + if (retval != -EIOCBQUEUED) + dio_await_completion(dio); + + if (drop_refcount(dio) == 0) { + retval = dio_complete(dio, offset, retval, false); + kmem_cache_free(dio_cache, dio); + } else + BUG_ON(retval != -EIOCBQUEUED); out: return retval; } EXPORT_SYMBOL(__blockdev_direct_IO); + +static __init int dio_init(void) +{ + dio_cache = KMEM_CACHE(dio, SLAB_PANIC); + return 0; +} +module_init(dio_init) |