Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753507Ab3FICUv (ORCPT ); Sat, 8 Jun 2013 22:20:51 -0400 Received: from mail-pb0-f48.google.com ([209.85.160.48]:49942 "EHLO mail-pb0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751246Ab3FICUN (ORCPT ); Sat, 8 Jun 2013 22:20:13 -0400 From: Kent Overstreet To: axboe@kernel.dk, tytso@mit.edu, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: Kent Overstreet Subject: [PATCH 26/26] Apply fire to dio code Date: Sat, 8 Jun 2013 19:19:08 -0700 Message-Id: <1370744348-15407-27-git-send-email-koverstreet@google.com> X-Mailer: git-send-email 1.8.3.rc1 In-Reply-To: <1370744348-15407-1-git-send-email-koverstreet@google.com> References: <1370744348-15407-1-git-send-email-koverstreet@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 46960 Lines: 1559 Near total rewrite of fs/direct-io.c. This makes use of our new bio splitting functionality, and the fact that generic_make_request() will take arbitrary size bios - we allocate a bio, pin pages to it directly, then call the getblocks() function to map it wherever the filesystem tells us - splitting as needed. This version will break btrfs - we need to add a new kind of hook so btrfs can do what it wants to more sanely that previously. Signed-off-by: Kent Overstreet --- fs/direct-io.c | 1318 ++++++++++++++------------------------------------------ 1 file changed, 331 insertions(+), 987 deletions(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index 6a5de20..3c32bf3 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -8,7 +8,7 @@ * 04Jul2002 Andrew Morton * Initial version * 11Sep2002 janetinc@us.ibm.com - * added readv/writev support. + * added readv/writev support. * 29Oct2002 Andrew Morton * rewrote bio_add_page() support. * 30Oct2002 pbadari@us.ibm.com @@ -39,183 +39,37 @@ #include #include -/* - * How many user pages to map in one call to get_user_pages(). This determines - * the size of a structure in the slab cache - */ -#define DIO_PAGES 64 - -/* - * This code generally works in units of "dio_blocks". A dio_block is - * somewhere between the hard sector size and the filesystem block size. it - * is determined on a per-invocation basis. When talking to the filesystem - * we need to convert dio_blocks to fs_blocks by scaling the dio_block quantity - * down by dio->blkfactor. Similarly, fs-blocksize quantities are converted - * to bio_block quantities by shifting left by blkfactor. - * - * If blkfactor is zero then the user's request was aligned to the filesystem's - * blocksize. - */ - /* dio_state only used in the submission path */ - struct dio_submit { - struct bio *bio; /* bio under assembly */ - unsigned blkbits; /* doesn't change */ - unsigned blkfactor; /* When we're using an alignment which - is finer than the filesystem's soft - blocksize, this specifies how much - finer. blkfactor=2 means 1/4-block - alignment. Does not change */ - unsigned start_zero_done; /* flag: sub-blocksize zeroing has - been performed at the start of a - write */ - int pages_in_io; /* approximate total IO pages */ - size_t size; /* total request size (doesn't change)*/ - 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 */ - get_block_t *get_block; /* block mapping 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 */ - - /* - * Deferred addition of a page to the dio. These variables are - * private to dio_send_cur_page(), submit_page_section() and - * dio_bio_add_page(). - */ - struct page *cur_page; /* The page */ - unsigned cur_page_offset; /* Offset into it, in bytes */ - unsigned cur_page_len; /* Nr of bytes at cur_page_offset */ - sector_t cur_page_block; /* Where it starts */ - loff_t cur_page_fs_offset; /* Offset in file */ - - /* - * Page fetching state. These variables belong to dio_refill_pages(). - */ - int curr_page; /* changes */ - int total_pages; /* doesn't change */ - unsigned long curr_user_address;/* changes */ - - /* - * Page queue. These variables belong to dio_refill_pages() and - * dio_get_page(). - */ - unsigned head; /* next page to process */ - unsigned tail; /* last valid page + 1 */ + get_block_t *get_block; /* block mapping function */ + dio_submit_t *submit_io; /* IO submition function */ + unsigned i_blkbits; }; /* 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 */ + int flags; /* doesn't change */ + int rw; + struct inode *inode; + loff_t i_size; /* i_size when submitted */ - void *private; /* copy from map_bh.b_private */ + 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 */ + int page_error; /* errno from get_user_pages() */ + int io_error; /* IO error in completion path */ + atomic_long_t refcount; /* direct_io_worker() and bios */ 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 - * allocation time. Don't add new fields after pages[] unless you - * wish that they not be zeroed. - */ - struct page *pages[DIO_PAGES]; /* page buffer */ -} ____cacheline_aligned_in_smp; + struct kiocb *iocb; /* kiocb */ + ssize_t result; /* IO result */ -static struct kmem_cache *dio_cache __read_mostly; - -/* - * How many pages are in the queue? - */ -static inline unsigned dio_pages_present(struct dio_submit *sdio) -{ - return sdio->tail - sdio->head; -} - -/* - * Go grab and pin some userspace pages. Typically we'll get 64 at a time. - */ -static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio) -{ - int ret; - int nr_pages; - - nr_pages = min(sdio->total_pages - sdio->curr_page, DIO_PAGES); - ret = get_user_pages_fast( - 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 && sdio->blocks_available && (dio->rw & WRITE)) { - struct page *page = ZERO_PAGE(0); - /* - * A memory fault, but the filesystem has some outstanding - * mapped blocks. We need to use those blocks up to avoid - * leaking stale data in the file. - */ - if (dio->page_errors == 0) - dio->page_errors = ret; - page_cache_get(page); - dio->pages[0] = page; - sdio->head = 0; - sdio->tail = 1; - ret = 0; - goto out; - } - - if (ret >= 0) { - sdio->curr_user_address += ret * PAGE_SIZE; - sdio->curr_page += ret; - sdio->head = 0; - sdio->tail = ret; - ret = 0; - } -out: - return ret; -} - -/* - * Get another userspace page. Returns an ERR_PTR on error. Pages are - * buffered inside the dio so that we can call get_user_pages() against a - * decent number of pages, less frequently. To provide nicer use of the - * L1 cache. - */ -static inline struct page *dio_get_page(struct dio *dio, - struct dio_submit *sdio) -{ - if (dio_pages_present(sdio) == 0) { - int ret; + struct bio bio; +}; - ret = dio_refill_pages(dio, sdio); - if (ret) - return ERR_PTR(ret); - BUG_ON(dio_pages_present(sdio) == 0); - } - return dio->pages[sdio->head++]; -} +static struct bio_set *dio_pool __read_mostly; /** * dio_complete() - called when all DIO BIO I/O has been completed @@ -234,25 +88,18 @@ static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret, bool is { ssize_t transferred = 0; - /* - * AIO submission can race with bio completion to get here while - * expecting to have the last io completed by bio completion. - * In that case -EIOCBQUEUED is in fact not an error we want - * to preserve through this call. - */ - if (ret == -EIOCBQUEUED) - ret = 0; - if (dio->result) { transferred = dio->result; + /* XXX: dio_send_bio() could do this */ + /* Check for short read case */ if ((dio->rw == READ) && ((offset + transferred) > dio->i_size)) transferred = dio->i_size - offset; } if (ret == 0) - ret = dio->page_errors; + ret = dio->page_error; if (ret == 0) ret = dio->io_error; if (ret == 0) @@ -267,53 +114,11 @@ static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret, bool is aio_complete(dio->iocb, ret, 0); } + bio_put(&dio->bio); return ret; } -static int dio_bio_complete(struct dio *dio, struct bio *bio); -/* - * Asynchronous IO callback. - */ -static void dio_bio_end_aio(struct bio *bio, int error) -{ - struct dio *dio = bio->bi_private; - unsigned long remaining; - unsigned long flags; - - /* cleanup the bio */ - dio_bio_complete(dio, bio); - - spin_lock_irqsave(&dio->bio_lock, flags); - remaining = --dio->refcount; - if (remaining == 1 && dio->waiter) - wake_up_process(dio->waiter); - spin_unlock_irqrestore(&dio->bio_lock, flags); - - if (remaining == 0) { - dio_complete(dio, dio->iocb->ki_pos, 0, true); - kmem_cache_free(dio_cache, dio); - } -} - -/* - * The BIO completion handler simply queues the BIO up for the process-context - * handler. - * - * During I/O bi_private points at the dio. After I/O, bi_private is used to - * implement a singly-linked list of completed BIOs, at dio->bio_list. - */ -static void dio_bio_end_io(struct bio *bio, int error) -{ - struct dio *dio = bio->bi_private; - unsigned long flags; - - spin_lock_irqsave(&dio->bio_lock, flags); - bio->bi_private = dio->bio_list; - dio->bio_list = bio; - if (--dio->refcount == 1 && dio->waiter) - wake_up_process(dio->waiter); - spin_unlock_irqrestore(&dio->bio_lock, flags); -} +#define DIO_WAKEUP (1U << 31) /** * dio_end_io - handle the end io action for the given bio @@ -327,693 +132,321 @@ static void dio_bio_end_io(struct bio *bio, int error) void dio_end_io(struct bio *bio, int error) { struct dio *dio = bio->bi_private; + unsigned long remaining; - if (dio->is_async) - dio_bio_end_aio(bio, error); - else - dio_bio_end_io(bio, error); + if (error) + dio->io_error = -EIO; + + if (dio->rw == READ) { + bio_check_pages_dirty(bio); /* transfers ownership */ + } else { + struct bio_vec *bv; + int i; + + bio_for_each_segment_all(bv, bio, i) + page_cache_release(bv->bv_page); + bio_put(bio); + } + + remaining = atomic_long_dec_return(&dio->refcount); + + if (remaining == DIO_WAKEUP) + wake_up_process(dio->waiter); + else if (!remaining) + dio_complete(dio, dio->iocb->ki_pos, 0, true); } EXPORT_SYMBOL_GPL(dio_end_io); -static inline void -dio_bio_alloc(struct dio *dio, struct dio_submit *sdio, - struct block_device *bdev, - sector_t first_sector, int nr_vecs) +static void dio_wait_completion(struct dio *dio) { - struct bio *bio; - - /* - * bio_alloc() is guaranteed to return a bio when called with - * __GFP_WAIT and we request a valid number of vectors. - */ - bio = bio_alloc(GFP_KERNEL, nr_vecs); + if (atomic_long_add_return(DIO_WAKEUP - 1, + &dio->refcount) == DIO_WAKEUP) + return; - bio->bi_bdev = bdev; - bio->bi_iter.bi_sector = first_sector; - if (dio->is_async) - bio->bi_end_io = dio_bio_end_aio; - else - bio->bi_end_io = dio_bio_end_io; + while (1) { + set_current_state(TASK_UNINTERRUPTIBLE); + if (atomic_long_read(&dio->refcount) == DIO_WAKEUP) + break; - sdio->bio = bio; - sdio->logical_offset_in_bio = sdio->cur_page_fs_offset; + io_schedule(); + } + __set_current_state(TASK_RUNNING); } /* - * In the AIO read case we speculatively dirty the pages before starting IO. - * During IO completion, any of these pages which happen to have been written - * back will be redirtied by bio_check_pages_dirty(). + * For reads we speculatively dirty the pages before starting IO. During IO + * completion, any of these pages which happen to have been written back will be + * redirtied by bio_check_pages_dirty(). * * bios hold a dio reference between submit_bio and ->end_io. */ -static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio) +static void dio_bio_submit(struct dio *dio, struct dio_submit *sdio, + struct bio *bio, loff_t offset) { - struct bio *bio = sdio->bio; - unsigned long flags; - - bio->bi_private = dio; - - spin_lock_irqsave(&dio->bio_lock, flags); - dio->refcount++; - spin_unlock_irqrestore(&dio->bio_lock, flags); - - if (dio->is_async && dio->rw == READ) - bio_set_pages_dirty(bio); + /* + * Read accounting is performed in submit_bio() + */ + if (dio->rw & WRITE) + task_io_account_write(bio->bi_iter.bi_size); if (sdio->submit_io) sdio->submit_io(dio->rw, bio, dio->inode, - sdio->logical_offset_in_bio); + offset >> sdio->i_blkbits); else submit_bio(dio->rw, bio); - - sdio->bio = NULL; - sdio->boundary = 0; - sdio->logical_offset_in_bio = 0; -} - -/* - * Release any resources in case of a failure - */ -static inline void dio_cleanup(struct dio *dio, struct dio_submit *sdio) -{ - while (dio_pages_present(sdio)) - page_cache_release(dio_get_page(dio, sdio)); -} - -/* - * Wait for the next BIO to complete. Remove it and return it. NULL is - * returned once all BIOs have been completed. This must only be called once - * all bios have been issued so that dio->refcount can only decrease. This - * requires that that the caller hold a reference on the dio. - */ -static struct bio *dio_await_one(struct dio *dio) -{ - unsigned long flags; - struct bio *bio = NULL; - - spin_lock_irqsave(&dio->bio_lock, flags); - - /* - * Wait as long as the list is empty and there are bios in flight. bio - * completion drops the count, maybe adds to the list, and wakes while - * holding the bio_lock so we don't need set_current_state()'s barrier - * and can call it after testing our condition. - */ - while (dio->refcount > 1 && dio->bio_list == NULL) { - __set_current_state(TASK_UNINTERRUPTIBLE); - dio->waiter = current; - spin_unlock_irqrestore(&dio->bio_lock, flags); - io_schedule(); - /* wake up sets us TASK_RUNNING */ - spin_lock_irqsave(&dio->bio_lock, flags); - dio->waiter = NULL; - } - if (dio->bio_list) { - bio = dio->bio_list; - dio->bio_list = bio->bi_private; - } - spin_unlock_irqrestore(&dio->bio_lock, flags); - return bio; } /* - * Process one completed BIO. No locks are held. + * Clean any dirty buffers in the blockdev mapping which alias newly-created + * file blocks. Only called for S_ISREG files - blockdevs do not set buffer_new */ -static int dio_bio_complete(struct dio *dio, struct bio *bio) +static void clean_blockdev_aliases(struct dio *dio, struct dio_submit *sdio, + struct buffer_head *map_bh) { - const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); - struct bio_vec *bvec; unsigned i; + unsigned nblocks; - if (!uptodate) - dio->io_error = -EIO; + nblocks = map_bh->b_size >> sdio->i_blkbits; - if (dio->is_async && dio->rw == READ) { - bio_check_pages_dirty(bio); /* transfers ownership */ - } else { - bio_for_each_segment_all(bvec, bio, i) { - struct page *page = bvec->bv_page; - - if (dio->rw == READ && !PageCompound(page)) - set_page_dirty_lock(page); - page_cache_release(page); - } - bio_put(bio); - } - return uptodate ? 0 : -EIO; + for (i = 0; i < nblocks; i++) + unmap_underlying_metadata(map_bh->b_bdev, + map_bh->b_blocknr + i); } -/* - * Wait on and process all in-flight BIOs. This must only be called once - * all bios have been issued so that the refcount can only decrease. - * This just waits for all bios to make it through dio_bio_complete. IO - * errors are propagated through dio->io_error and should be propagated via - * dio_complete(). - */ -static void dio_await_completion(struct dio *dio) -{ - struct bio *bio; - do { - bio = dio_await_one(dio); - if (bio) - dio_bio_complete(dio, bio); - } while (bio); -} +struct dio_mapping { + enum { + MAP_MAPPED, + MAP_NEW, + MAP_UNMAPPED, + } state; -/* - * A really large O_DIRECT read or write can generate a lot of BIOs. So - * to keep the memory consumption sane we periodically reap any completed BIOs - * during the BIO generation phase. - * - * This also helps to limit the peak amount of pinned userspace memory. - */ -static inline int dio_bio_reap(struct dio *dio, struct dio_submit *sdio) -{ - int ret = 0; - - if (sdio->reap_counter++ >= 64) { - while (dio->bio_list) { - unsigned long flags; - struct bio *bio; - int ret2; - - spin_lock_irqsave(&dio->bio_lock, flags); - bio = dio->bio_list; - dio->bio_list = bio->bi_private; - spin_unlock_irqrestore(&dio->bio_lock, flags); - ret2 = dio_bio_complete(dio, bio); - if (ret == 0) - ret = ret2; - } - sdio->reap_counter = 0; - } - return ret; -} + struct block_device *bdev; + sector_t sector; + size_t size; +}; -/* - * Call into the fs to map some more disk blocks. We record the current number - * 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, - * it uses the passed inode-relative block number as the file offset, as usual. - * - * get_block() is passed the number of i_blkbits-sized blocks which direct_io - * has remaining to do. The fs should not map more than this number of blocks. - * - * If the fs has mapped a lot of blocks, it should populate bh->b_size to - * indicate how much contiguous disk space has been made available at - * bh->b_blocknr. - * - * If *any* of the mapped blocks are new, then the fs must set buffer_new(). - * This isn't very efficient... - * - * In the case of filesystem holes: the fs may return an arbitrarily-large - * hole by returning an appropriate value in b_size and by clearing - * 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, - struct buffer_head *map_bh) +static int get_blocks(struct dio *dio, struct dio_submit *sdio, + loff_t offset, size_t size, + struct dio_mapping *map) { - int ret; - sector_t fs_startblk; /* Into file, in filesystem-sized blocks */ - sector_t fs_endblk; /* Into file, in filesystem-sized blocks */ - unsigned long fs_count; /* Number of filesystem-sized blocks */ - int create; - unsigned int i_blkbits = sdio->blkbits + sdio->blkfactor; + struct buffer_head map_bh = { 0, }; + int ret, create; + unsigned i_mask = (1 << sdio->i_blkbits) - 1; + unsigned fs_offset = offset & i_mask; + sector_t fs_block = offset >> sdio->i_blkbits; /* - * If there was a memory error and we've overwritten all the - * mapped blocks then we can now return that memory error + * For writes inside i_size on a DIO_SKIP_HOLES filesystem we + * forbid block creations: only overwrites are permitted. + * We will return early to the caller once we see an + * unmapped buffer head returned, and the caller will fall + * back to buffered I/O. + * + * Otherwise the decision is left to the get_blocks method, + * which may decide to handle it or also return an unmapped + * buffer head. */ - ret = dio->page_errors; - if (ret == 0) { - BUG_ON(sdio->block_in_file >= sdio->final_block_in_request); - fs_startblk = sdio->block_in_file >> sdio->blkfactor; - fs_endblk = (sdio->final_block_in_request - 1) >> - sdio->blkfactor; - fs_count = fs_endblk - fs_startblk + 1; - - map_bh->b_state = 0; - map_bh->b_size = fs_count << i_blkbits; - - /* - * For writes inside i_size on a DIO_SKIP_HOLES filesystem we - * forbid block creations: only overwrites are permitted. - * We will return early to the caller once we see an - * unmapped buffer head returned, and the caller will fall - * back to buffered I/O. - * - * Otherwise the decision is left to the get_blocks method, - * which may decide to handle it or also return an unmapped - * buffer head. - */ - create = dio->rw & WRITE; - if (dio->flags & DIO_SKIP_HOLES) { - if (sdio->block_in_file < (i_size_read(dio->inode) >> - sdio->blkbits)) - create = 0; - } - - ret = (*sdio->get_block)(dio->inode, fs_startblk, - map_bh, create); - - /* Store for completion */ - dio->private = map_bh->b_private; + create = dio->rw & WRITE; + if (dio->flags & DIO_SKIP_HOLES) { + if (fs_block < dio->i_size >> sdio->i_blkbits) + create = 0; } - return ret; -} -/* - * There is no bio. Make one now. - */ -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; + map_bh.b_state = 0; + map_bh.b_size = size + fs_offset; - ret = dio_bio_reap(dio, sdio); + ret = sdio->get_block(dio->inode, fs_block, + &map_bh, create); if (ret) - goto out; - 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, sdio, map_bh->b_bdev, sector, nr_pages); - sdio->boundary = 0; -out: - return ret; -} + return ret; -/* - * Attempt to put the current chunk of 'cur_page' into the current BIO. If - * that was successful then update final_block_in_bio and take a ref against - * the just-added page. - * - * Return zero on success. Non-zero means the caller needs to start a new BIO. - */ -static inline int dio_bio_add_page(struct dio_submit *sdio) -{ - int ret; + /* Store for completion */ + dio->private = map_bh.b_private; - 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 ((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; - } - return ret; -} - -/* - * Put cur_page under IO. The section of cur_page which is described by - * cur_page_offset,cur_page_len is put into a BIO. The section of cur_page - * starts on-disk at cur_page_block. - * - * We take a ref against the page here (on behalf of its presence in the bio). - * - * 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 inline int dio_send_cur_page(struct dio *dio, struct dio_submit *sdio, - struct buffer_head *map_bh) -{ - int ret = 0; + if (!buffer_mapped(&map_bh)) + map->state = MAP_UNMAPPED; + else if (buffer_new(&map_bh)) + map->state = MAP_NEW; + else + map->state = MAP_MAPPED; - 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_iter.bi_size; + /* Holes always 1 block? */ + if (map->state == MAP_UNMAPPED) + map_bh.b_size = 1 << sdio->i_blkbits; - /* - * See whether this new request is contiguous with the old. - * - * Btrfs cannot handle having logically non-contiguous requests - * submitted. For example if you have - * - * Logical: [0-4095][HOLE][8192-12287] - * Physical: [0-4095] [4096-8191] - * - * We cannot submit those pages together as one BIO. So if our - * current logical offset in the file does not equal what would - * be the next logical offset in the bio, submit the bio we - * have. - */ - if (sdio->final_block_in_bio != sdio->cur_page_block || - cur_offset != bio_next_offset) - dio_bio_submit(dio, sdio); - } + if (map->state == MAP_NEW) + clean_blockdev_aliases(dio, sdio, &map_bh); - if (sdio->bio == NULL) { - ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh); - if (ret) - goto out; - } + BUG_ON(map_bh.b_size <= fs_offset); + + map->bdev = map_bh.b_bdev; + map->sector = (map_bh.b_blocknr << (sdio->i_blkbits - 9)) + + (fs_offset >> 9); + map->size = min(map_bh.b_size - fs_offset, size); - 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(sdio); - BUG_ON(ret != 0); - } - } -out: return ret; } -/* - * An autonomous function to put a chunk of a page under deferred IO. - * - * The caller doesn't actually know (or care) whether this piece of page is in - * a BIO, or is under IO or whatever. We just take care of all possible - * situations here. The separation between the logic of do_direct_IO() and - * that of submit_page_section() is important for clarity. Please don't break. - * - * The chunk of page starts on-disk at blocknr. - * - * We perform deferred IO, by recording the last-submitted page inside our - * private part of the dio structure. If possible, we just expand the IO - * across that page here. - * - * If that doesn't work out then we put the old page into the bio and add this - * page to the dio instead. - */ -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) +static void dio_write_zeroes(struct dio *dio, struct bio *parent, + sector_t sector, size_t size) { - int ret = 0; + unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE); + struct bio *bio = bio_alloc(GFP_KERNEL, pages); - if (dio->rw & WRITE) { - /* - * Read accounting is performed in submit_bio() - */ - task_io_account_write(len); + while (pages--) { + bio->bi_io_vec[pages].bv_page = ZERO_PAGE(0); + bio->bi_io_vec[pages].bv_len = PAGE_SIZE; + bio->bi_io_vec[pages].bv_offset = 0; } - /* - * Can we just grow the current page's presence in the dio? - */ - 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; - goto out; - } - - /* - * If there's a deferred page already there then send it. - */ - 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) - return ret; - } + bio->bi_bdev = parent->bi_bdev; + bio->bi_iter.bi_sector = sector; + bio->bi_iter.bi_size = size; - page_cache_get(page); /* It is in dio */ - 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: - /* - * If sdio->boundary then we want to schedule the IO now to - * avoid metadata seeks. - */ - if (sdio->boundary) { - ret = dio_send_cur_page(dio, sdio, map_bh); - dio_bio_submit(dio, sdio); - page_cache_release(sdio->cur_page); - sdio->cur_page = NULL; - } - return ret; + bio_chain(bio, parent); + submit_bio(WRITE, bio); } -/* - * Clean any dirty buffers in the blockdev mapping which alias newly-created - * file blocks. Only called for S_ISREG files - blockdevs do not set - * buffer_new - */ -static void clean_blockdev_aliases(struct dio *dio, struct buffer_head *map_bh) +static void dio_zero_partial_block(struct dio *dio, struct dio_submit *sdio, + struct bio *bio, loff_t offset, + struct dio_mapping *map) { - unsigned i; - unsigned nblocks; - - nblocks = map_bh->b_size >> dio->inode->i_blkbits; - - for (i = 0; i < nblocks; i++) { - unmap_underlying_metadata(map_bh->b_bdev, - map_bh->b_blocknr + i); + if ((dio->rw & WRITE) && map->state == MAP_NEW) { + unsigned blksize = 1 << sdio->i_blkbits; + unsigned blkmask = blksize - 1; + unsigned front = offset & blkmask; + unsigned back = (offset + bio->bi_iter.bi_size) & blkmask; + + if (front) + dio_write_zeroes(dio, bio, + bio->bi_iter.bi_sector - (front >> 9), + front); + + if (back) + dio_write_zeroes(dio, bio, bio_end_sector(bio), + blksize - back); } } -/* - * If we are not writing the entire block and get_block() allocated - * the block for us, we need to fill-in the unused portion of the - * block with zeros. This happens only if user-buffer, fileoffset or - * io length is not filesystem block-size multiple. - * - * `end' is zero if we're doing the start of the IO, 1 at the end of the - * IO. - */ -static inline void dio_zero_block(struct dio *dio, struct dio_submit *sdio, - int end, struct buffer_head *map_bh) +static int dio_send_bio(struct dio *dio, struct dio_submit *sdio, + struct bio *bio, loff_t offset) { - unsigned dio_blocks_per_fs_block; - unsigned this_chunk_blocks; /* In dio_blocks */ - unsigned this_chunk_bytes; - struct page *page; + struct dio_mapping map; + struct bio *split; + int ret; - sdio->start_zero_done = 1; - if (!sdio->blkfactor || !buffer_new(map_bh)) - return; + while (1) { + if (dio->rw == READ && offset >= dio->i_size) + break; - dio_blocks_per_fs_block = 1 << sdio->blkfactor; - this_chunk_blocks = sdio->block_in_file & (dio_blocks_per_fs_block - 1); + ret = get_blocks(dio, sdio, offset, bio->bi_iter.bi_size, &map); + if (ret) + break; - if (!this_chunk_blocks) - return; + if (map.state != MAP_UNMAPPED) { + split = bio_next_split(bio, map.size >> 9, + GFP_KERNEL, fs_bio_set); - /* - * We need to zero out part of an fs block. It is either at the - * beginning or the end of the fs block. - */ - if (end) - this_chunk_blocks = dio_blocks_per_fs_block - this_chunk_blocks; + if (split != bio) + bio_chain(split, bio); - this_chunk_bytes = this_chunk_blocks << sdio->blkbits; + split->bi_bdev = map.bdev; + split->bi_iter.bi_sector = map.sector; - page = ZERO_PAGE(0); - if (submit_page_section(dio, sdio, page, 0, this_chunk_bytes, - sdio->next_block_for_io, map_bh)) - return; + dio_zero_partial_block(dio, sdio, split, offset, &map); - sdio->next_block_for_io += this_chunk_blocks; -} + dio->result += map.size; + dio_bio_submit(dio, sdio, split, offset); -/* - * Walk the user pages, and the file, mapping blocks to disk and generating - * a sequence of (page,offset,len,block) mappings. These mappings are injected - * into submit_page_section(), which takes care of the next stage of submission - * - * Direct IO against a blockdev is different from a file. Because we can - * happily perform page-sized but 512-byte aligned IOs. It is important that - * blockdev IO be able to have fine alignment and large sizes. - * - * So what we do is to permit the ->get_block function to populate bh.b_size - * with the size of IO which is permitted at this offset and this i_blkbits. - * - * For best results, the blockdev should be set up with 512-byte i_blkbits and - * 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, - 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; - int ret = 0; - - /* The I/O can start at any block offset within the first page */ - block_in_page = sdio->first_block_in_page; - - 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; - } + if (split == bio) + return 0; + } else { + /* Hole */ - while (block_in_page < blocks_per_page) { - unsigned offset_in_page = block_in_page << blkbits; - unsigned this_chunk_bytes; /* # of bytes mapped */ - unsigned this_chunk_blocks; /* # of blocks */ - unsigned u; - - 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, sdio, map_bh); - if (ret) { - page_cache_release(page); - goto out; - } - if (!buffer_mapped(map_bh)) - goto do_holes; - - 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, map_bh); - - if (!sdio->blkfactor) - goto do_holes; - - blkmask = (1 << sdio->blkfactor) - 1; - dio_remainder = (sdio->block_in_file & blkmask); - - /* - * If we are at the start of IO and that IO - * starts partway into a fs-block, - * dio_remainder will be non-zero. If the IO - * is a read then we can simply advance the IO - * cursor to the first block which is to be - * read. But if the IO is a write and the - * block was newly allocated we cannot do that; - * the start of the fs block must be zeroed out - * on-disk - */ - if (!buffer_new(map_bh)) - sdio->next_block_for_io += dio_remainder; - sdio->blocks_available -= dio_remainder; - } -do_holes: - /* Handle holes */ - if (!buffer_mapped(map_bh)) { - loff_t i_size_aligned; - - /* AKPM: eargh, -ENOTBLK is a hack */ - if (dio->rw & WRITE) { - page_cache_release(page); - return -ENOTBLK; - } - - /* - * Be sure to account for a partial block as the - * last block in the file - */ - i_size_aligned = ALIGN(i_size_read(dio->inode), - 1 << blkbits); - if (sdio->block_in_file >= - i_size_aligned >> blkbits) { - /* We hit eof */ - page_cache_release(page); - goto out; - } - zero_user(page, block_in_page << blkbits, - 1 << blkbits); - sdio->block_in_file++; - block_in_page++; - goto next_block; + /* AKPM: eargh, -ENOTBLK is a hack */ + if (dio->rw & WRITE) { + ret = -ENOTBLK; + break; } - /* - * If we're performing IO which has an alignment which - * is finer than the underlying fs, go check to see if - * we must zero out the start of this block. - */ - 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 = sdio->blocks_available; - u = (PAGE_SIZE - offset_in_page) >> blkbits; - if (this_chunk_blocks > u) - this_chunk_blocks = u; - 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); - - if (this_chunk_blocks == sdio->blocks_available) - 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; - } - sdio->next_block_for_io += this_chunk_blocks; - - sdio->block_in_file += this_chunk_blocks; - block_in_page += this_chunk_blocks; - sdio->blocks_available -= this_chunk_blocks; -next_block: - BUG_ON(sdio->block_in_file > sdio->final_block_in_request); - if (sdio->block_in_file == sdio->final_block_in_request) + swap(bio->bi_iter.bi_size, map.size); + zero_fill_bio(bio); + swap(bio->bi_iter.bi_size, map.size); + + dio->result += map.size; + bio_advance(bio, map.size); + + if (!bio->bi_iter.bi_size) break; } - /* Drop the ref which was taken in get_user_pages() */ - page_cache_release(page); - block_in_page = 0; + offset += map.size; } -out: + + bio_endio(bio, 0); return ret; } -static inline int drop_refcount(struct dio *dio) +static int dio_alloc_bios(struct dio *dio, struct dio_submit *sdio, + const struct iovec *iov, loff_t offset, + unsigned long nr_segs, unsigned nr_pages) { - int ret2; - unsigned long flags; + ssize_t ret; + size_t seg_done = 0; + unsigned seg = 0; + struct bio *bio; - /* - * Sync will always be dropping the final ref and completing the - * operation. AIO can if it was a broken operation described above or - * in fact if all the bios race to complete before we get here. In - * that case dio_complete() translates the EIOCBQUEUED into the proper - * return code that the caller will hand to aio_complete(). - * - * This is managed by the bio_lock instead of being an atomic_t so that - * completion paths can drop their ref and use the remaining count to - * decide to wake the submission path atomically. - */ - spin_lock_irqsave(&dio->bio_lock, flags); - ret2 = --dio->refcount; - spin_unlock_irqrestore(&dio->bio_lock, flags); - return ret2; + bio = &dio->bio; + bio_get(bio); + goto start; + + while (seg < nr_segs) { + BUG_ON(!nr_pages); + + bio = bio_alloc(GFP_KERNEL, + min_t(unsigned, BIO_MAX_PAGES, nr_pages)); +start: + bio->bi_private = dio; + bio->bi_end_io = dio_end_io; + + while (bio->bi_vcnt < bio->bi_max_vecs && + seg < nr_segs) { + ret = bio_get_user_pages(bio, + (size_t) iov[seg].iov_base + seg_done, + iov[seg].iov_len - seg_done, + dio->rw == READ); + if (ret < 0) { + struct bio_vec *bv; + int i; + + bio_for_each_segment_all(bv, bio, i) + page_cache_release(bv->bv_page); + bio_put(bio); + + dio->page_error = ret; + return 0; + } + + seg_done += ret; + + if (seg_done == iov[seg].iov_len) { + seg++; + seg_done = 0; + } + } + + nr_pages -= bio->bi_vcnt; + + if (dio->rw == READ) + bio_set_pages_dirty(bio); + + atomic_long_inc(&dio->refcount); + ret = dio_send_bio(dio, sdio, bio, offset + dio->result); + if (ret) + return ret; + } + + return 0; } /* @@ -1041,76 +474,57 @@ static inline int drop_refcount(struct dio *dio) * individual fields and will generate much worse code. This is important * for the whole file. */ -static inline ssize_t +static ssize_t do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, - struct block_device *bdev, const struct iovec *iov, loff_t offset, + struct block_device *bdev, const struct iovec *iov, loff_t offset, unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io, dio_submit_t submit_io, int flags) { - int seg; - size_t size; - unsigned long addr; - unsigned i_blkbits = ACCESS_ONCE(inode->i_blkbits); - unsigned blkbits = i_blkbits; - unsigned blocksize_mask = (1 << blkbits) - 1; - ssize_t retval = -EINVAL; - loff_t end = offset; + unsigned nr_pages = 0, blocksize_mask; + size_t size = 0; + ssize_t retval = 0; + const struct iovec *v; struct dio *dio; - struct dio_submit sdio = { 0, }; - unsigned long user_addr; - size_t bytes; - struct buffer_head map_bh = { 0, }; + struct dio_submit sdio; struct blk_plug plug; if (rw & WRITE) rw = WRITE_ODIRECT; - /* - * Avoid references to bdev if not absolutely needed to give - * the early prefetch in the caller enough time. - */ + sdio.get_block = get_block; + sdio.submit_io = submit_io; + sdio.i_blkbits = ACCESS_ONCE(inode->i_blkbits); - if (offset & blocksize_mask) { - if (bdev) - blkbits = blksize_bits(bdev_logical_block_size(bdev)); - blocksize_mask = (1 << blkbits) - 1; - if (offset & blocksize_mask) - goto out; - } + for (v = iov; v < iov + nr_segs; v++) { + unsigned offset = (size_t) v->iov_base & (PAGE_SIZE - 1); - /* Check the memory alignment. Blocks cannot straddle pages */ - for (seg = 0; seg < nr_segs; seg++) { - addr = (unsigned long)iov[seg].iov_base; - size = iov[seg].iov_len; - end += size; - if (unlikely((addr & blocksize_mask) || - (size & blocksize_mask))) { - if (bdev) - blkbits = blksize_bits( - bdev_logical_block_size(bdev)); - blocksize_mask = (1 << blkbits) - 1; - if ((addr & blocksize_mask) || (size & blocksize_mask)) - goto out; - } + nr_pages += DIV_ROUND_UP(offset + v->iov_len, PAGE_SIZE); + size += v->iov_len; } /* watch out for a 0 len io from a tricksy fs */ - if (rw == READ && end == offset) + if (rw == READ && !size) return 0; - dio = kmem_cache_alloc(dio_cache, GFP_KERNEL); - retval = -ENOMEM; - if (!dio) - goto out; + blocksize_mask = (1 << sdio.i_blkbits) - 1; + /* - * Believe it or not, zeroing out the page array caused a .5% - * performance regression in a database benchmark. So, we take - * care to only zero out what's needed. + * Avoid references to bdev if not absolutely needed to give + * the early prefetch in the caller enough time. */ - memset(dio, 0, offsetof(struct dio, pages)); - dio->flags = flags; - if (dio->flags & DIO_LOCKING) { + if (unlikely((offset & blocksize_mask) || + (size & blocksize_mask))) { + if (bdev) + blocksize_mask = roundup_pow_of_two( + bdev_logical_block_size(bdev)) - 1; + + if ((offset & blocksize_mask) || + (size & blocksize_mask)) + return -EINVAL; + } + + if (flags & DIO_LOCKING) { if (rw == READ) { struct address_space *mapping = iocb->ki_filp->f_mapping; @@ -1119,11 +533,10 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, mutex_lock(&inode->i_mutex); retval = filemap_write_and_wait_range(mapping, offset, - end - 1); + offset + size - 1); if (retval) { mutex_unlock(&inode->i_mutex); - kmem_cache_free(dio_cache, dio); - goto out; + return retval; } } } @@ -1133,83 +546,27 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, */ atomic_inc(&inode->i_dio_count); - /* - * For file extending writes updating i_size before data - * writeouts complete can expose uninitialized blocks. So - * even for AIO, we need to wait for i/o to complete before - * returning in this case. - */ - dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) && - (end > i_size_read(inode))); - - retval = 0; - - dio->inode = inode; - dio->rw = rw; - sdio.blkbits = blkbits; - sdio.blkfactor = 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); - } + dio = container_of(bio_alloc_bioset(GFP_KERNEL, + min_t(unsigned, BIO_MAX_PAGES, nr_pages), + dio_pool), + struct dio, bio); + + dio->flags = flags; + dio->rw = rw; + dio->inode = inode; + dio->i_size = i_size_read(inode); + dio->end_io = end_io; + dio->private = NULL; + dio->page_error = 0; + dio->io_error = 0; + atomic_long_set(&dio->refcount, 1); + dio->waiter = current; + dio->iocb = iocb; + dio->result = 0; blk_start_plug(&plug); - 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 */ + retval = dio_alloc_bios(dio, &sdio, iov, offset, nr_segs, nr_pages); if (retval == -ENOTBLK) { /* @@ -1218,33 +575,10 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, */ 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); blk_finish_plug(&plug); /* - * 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. @@ -1260,20 +594,28 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, * 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) { + /* + * For file extending writes updating i_size before data + * writeouts complete can expose uninitialized blocks. So + * even for AIO, we need to wait for i/o to complete before + * returning in this case. + */ + if (!is_sync_kiocb(iocb) && + retval == 0 && dio->result && + ((rw == READ) || + (offset + size <= dio->i_size && + dio->result == size))) { + if (atomic_long_dec_and_test(&dio->refcount)) + retval = dio_complete(dio, offset, retval, false); + else + retval = -EIOCBQUEUED; + } else { + dio_wait_completion(dio); retval = dio_complete(dio, offset, retval, false); - kmem_cache_free(dio_cache, dio); - } else - BUG_ON(retval != -EIOCBQUEUED); + BUG_ON(retval == -EIOCBQUEUED); + } -out: return retval; } @@ -1304,7 +646,9 @@ EXPORT_SYMBOL(__blockdev_direct_IO); static __init int dio_init(void) { - dio_cache = KMEM_CACHE(dio, SLAB_PANIC); + dio_pool = bioset_create(4, offsetof(struct dio, bio)); + if (!dio_pool) + return -ENOMEM; return 0; } module_init(dio_init) -- 1.8.3.rc1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/