diff options
Diffstat (limited to 'block/ll_rw_blk.c')
-rw-r--r-- | block/ll_rw_blk.c | 456 |
1 files changed, 339 insertions, 117 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index 3d0422f4845..1932a56f5e4 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -347,7 +347,6 @@ unsigned blk_ordered_req_seq(struct request *rq) void blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error) { struct request *rq; - int uptodate; if (error && !q->orderr) q->orderr = error; @@ -361,15 +360,11 @@ void blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error) /* * Okay, sequence complete. */ - uptodate = 1; - if (q->orderr) - uptodate = q->orderr; - q->ordseq = 0; rq = q->orig_bar_rq; - end_that_request_first(rq, uptodate, rq->hard_nr_sectors); - end_that_request_last(rq, uptodate); + if (__blk_end_request(rq, q->orderr, blk_rq_bytes(rq))) + BUG(); } static void pre_flush_end_io(struct request *rq, int error) @@ -486,9 +481,9 @@ int blk_do_ordered(struct request_queue *q, struct request **rqp) * ORDERED_NONE while this request is on it. */ blkdev_dequeue_request(rq); - end_that_request_first(rq, -EOPNOTSUPP, - rq->hard_nr_sectors); - end_that_request_last(rq, -EOPNOTSUPP); + if (__blk_end_request(rq, -EOPNOTSUPP, + blk_rq_bytes(rq))) + BUG(); *rqp = NULL; return 0; } @@ -726,6 +721,45 @@ void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b) EXPORT_SYMBOL(blk_queue_stack_limits); /** + * blk_queue_dma_drain - Set up a drain buffer for excess dma. + * + * @q: the request queue for the device + * @buf: physically contiguous buffer + * @size: size of the buffer in bytes + * + * Some devices have excess DMA problems and can't simply discard (or + * zero fill) the unwanted piece of the transfer. They have to have a + * real area of memory to transfer it into. The use case for this is + * ATAPI devices in DMA mode. If the packet command causes a transfer + * bigger than the transfer size some HBAs will lock up if there + * aren't DMA elements to contain the excess transfer. What this API + * does is adjust the queue so that the buf is always appended + * silently to the scatterlist. + * + * Note: This routine adjusts max_hw_segments to make room for + * appending the drain buffer. If you call + * blk_queue_max_hw_segments() or blk_queue_max_phys_segments() after + * calling this routine, you must set the limit to one fewer than your + * device can support otherwise there won't be room for the drain + * buffer. + */ +int blk_queue_dma_drain(struct request_queue *q, void *buf, + unsigned int size) +{ + if (q->max_hw_segments < 2 || q->max_phys_segments < 2) + return -EINVAL; + /* make room for appending the drain */ + --q->max_hw_segments; + --q->max_phys_segments; + q->dma_drain_buffer = buf; + q->dma_drain_size = size; + + return 0; +} + +EXPORT_SYMBOL_GPL(blk_queue_dma_drain); + +/** * blk_queue_segment_boundary - set boundary rules for segment merging * @q: the request queue for the device * @mask: the memory boundary mask @@ -1379,6 +1413,16 @@ new_segment: bvprv = bvec; } /* segments in rq */ + if (q->dma_drain_size) { + sg->page_link &= ~0x02; + sg = sg_next(sg); + sg_set_page(sg, virt_to_page(q->dma_drain_buffer), + q->dma_drain_size, + ((unsigned long)q->dma_drain_buffer) & + (PAGE_SIZE - 1)); + nsegs++; + } + if (sg) sg_mark_end(sg); @@ -3437,29 +3481,36 @@ static void blk_recalc_rq_sectors(struct request *rq, int nsect) } } -static int __end_that_request_first(struct request *req, int uptodate, +/** + * __end_that_request_first - end I/O on a request + * @req: the request being processed + * @error: 0 for success, < 0 for error + * @nr_bytes: number of bytes to complete + * + * Description: + * Ends I/O on a number of bytes attached to @req, and sets it up + * for the next range of segments (if any) in the cluster. + * + * Return: + * 0 - we are done with this request, call end_that_request_last() + * 1 - still buffers pending for this request + **/ +static int __end_that_request_first(struct request *req, int error, int nr_bytes) { - int total_bytes, bio_nbytes, error, next_idx = 0; + int total_bytes, bio_nbytes, next_idx = 0; struct bio *bio; blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE); /* - * extend uptodate bool to allow < 0 value to be direct io error - */ - error = 0; - if (end_io_error(uptodate)) - error = !uptodate ? -EIO : uptodate; - - /* * for a REQ_BLOCK_PC request, we want to carry any eventual * sense key with us all the way through */ if (!blk_pc_request(req)) req->errors = 0; - if (!uptodate) { + if (error) { if (blk_fs_request(req) && !(req->cmd_flags & REQ_QUIET)) printk("end_request: I/O error, dev %s, sector %llu\n", req->rq_disk ? req->rq_disk->disk_name : "?", @@ -3553,49 +3604,6 @@ static int __end_that_request_first(struct request *req, int uptodate, return 1; } -/** - * end_that_request_first - end I/O on a request - * @req: the request being processed - * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error - * @nr_sectors: number of sectors to end I/O on - * - * Description: - * Ends I/O on a number of sectors attached to @req, and sets it up - * for the next range of segments (if any) in the cluster. - * - * Return: - * 0 - we are done with this request, call end_that_request_last() - * 1 - still buffers pending for this request - **/ -int end_that_request_first(struct request *req, int uptodate, int nr_sectors) -{ - return __end_that_request_first(req, uptodate, nr_sectors << 9); -} - -EXPORT_SYMBOL(end_that_request_first); - -/** - * end_that_request_chunk - end I/O on a request - * @req: the request being processed - * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error - * @nr_bytes: number of bytes to complete - * - * Description: - * Ends I/O on a number of bytes attached to @req, and sets it up - * for the next range of segments (if any). Like end_that_request_first(), - * but deals with bytes instead of sectors. - * - * Return: - * 0 - we are done with this request, call end_that_request_last() - * 1 - still buffers pending for this request - **/ -int end_that_request_chunk(struct request *req, int uptodate, int nr_bytes) -{ - return __end_that_request_first(req, uptodate, nr_bytes); -} - -EXPORT_SYMBOL(end_that_request_chunk); - /* * splice the completion data to a local structure and hand off to * process_completion_queue() to complete the requests @@ -3675,17 +3683,15 @@ EXPORT_SYMBOL(blk_complete_request); /* * queue lock must be held */ -void end_that_request_last(struct request *req, int uptodate) +static void end_that_request_last(struct request *req, int error) { struct gendisk *disk = req->rq_disk; - int error; - /* - * extend uptodate bool to allow < 0 value to be direct io error - */ - error = 0; - if (end_io_error(uptodate)) - error = !uptodate ? -EIO : uptodate; + if (blk_rq_tagged(req)) + blk_queue_end_tag(req->q, req); + + if (blk_queued_rq(req)) + blkdev_dequeue_request(req); if (unlikely(laptop_mode) && blk_fs_request(req)) laptop_io_completion(); @@ -3704,32 +3710,54 @@ void end_that_request_last(struct request *req, int uptodate) disk_round_stats(disk); disk->in_flight--; } + if (req->end_io) req->end_io(req, error); - else + else { + if (blk_bidi_rq(req)) + __blk_put_request(req->next_rq->q, req->next_rq); + __blk_put_request(req->q, req); + } } -EXPORT_SYMBOL(end_that_request_last); - static inline void __end_request(struct request *rq, int uptodate, - unsigned int nr_bytes, int dequeue) + unsigned int nr_bytes) { - if (!end_that_request_chunk(rq, uptodate, nr_bytes)) { - if (dequeue) - blkdev_dequeue_request(rq); - add_disk_randomness(rq->rq_disk); - end_that_request_last(rq, uptodate); - } + int error = 0; + + if (uptodate <= 0) + error = uptodate ? uptodate : -EIO; + + __blk_end_request(rq, error, nr_bytes); } -static unsigned int rq_byte_size(struct request *rq) +/** + * blk_rq_bytes - Returns bytes left to complete in the entire request + **/ +unsigned int blk_rq_bytes(struct request *rq) { if (blk_fs_request(rq)) return rq->hard_nr_sectors << 9; return rq->data_len; } +EXPORT_SYMBOL_GPL(blk_rq_bytes); + +/** + * blk_rq_cur_bytes - Returns bytes left to complete in the current segment + **/ +unsigned int blk_rq_cur_bytes(struct request *rq) +{ + if (blk_fs_request(rq)) + return rq->current_nr_sectors << 9; + + if (rq->bio) + return rq->bio->bi_size; + + return rq->data_len; +} +EXPORT_SYMBOL_GPL(blk_rq_cur_bytes); /** * end_queued_request - end all I/O on a queued request @@ -3744,7 +3772,7 @@ static unsigned int rq_byte_size(struct request *rq) **/ void end_queued_request(struct request *rq, int uptodate) { - __end_request(rq, uptodate, rq_byte_size(rq), 1); + __end_request(rq, uptodate, blk_rq_bytes(rq)); } EXPORT_SYMBOL(end_queued_request); @@ -3761,7 +3789,7 @@ EXPORT_SYMBOL(end_queued_request); **/ void end_dequeued_request(struct request *rq, int uptodate) { - __end_request(rq, uptodate, rq_byte_size(rq), 0); + __end_request(rq, uptodate, blk_rq_bytes(rq)); } EXPORT_SYMBOL(end_dequeued_request); @@ -3787,10 +3815,159 @@ EXPORT_SYMBOL(end_dequeued_request); **/ void end_request(struct request *req, int uptodate) { - __end_request(req, uptodate, req->hard_cur_sectors << 9, 1); + __end_request(req, uptodate, req->hard_cur_sectors << 9); } EXPORT_SYMBOL(end_request); +/** + * blk_end_io - Generic end_io function to complete a request. + * @rq: the request being processed + * @error: 0 for success, < 0 for error + * @nr_bytes: number of bytes to complete @rq + * @bidi_bytes: number of bytes to complete @rq->next_rq + * @drv_callback: function called between completion of bios in the request + * and completion of the request. + * If the callback returns non 0, this helper returns without + * completion of the request. + * + * Description: + * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. + * If @rq has leftover, sets it up for the next range of segments. + * + * Return: + * 0 - we are done with this request + * 1 - this request is not freed yet, it still has pending buffers. + **/ +static int blk_end_io(struct request *rq, int error, int nr_bytes, + int bidi_bytes, int (drv_callback)(struct request *)) +{ + struct request_queue *q = rq->q; + unsigned long flags = 0UL; + + if (blk_fs_request(rq) || blk_pc_request(rq)) { + if (__end_that_request_first(rq, error, nr_bytes)) + return 1; + + /* Bidi request must be completed as a whole */ + if (blk_bidi_rq(rq) && + __end_that_request_first(rq->next_rq, error, bidi_bytes)) + return 1; + } + + /* Special feature for tricky drivers */ + if (drv_callback && drv_callback(rq)) + return 1; + + add_disk_randomness(rq->rq_disk); + + spin_lock_irqsave(q->queue_lock, flags); + end_that_request_last(rq, error); + spin_unlock_irqrestore(q->queue_lock, flags); + + return 0; +} + +/** + * blk_end_request - Helper function for drivers to complete the request. + * @rq: the request being processed + * @error: 0 for success, < 0 for error + * @nr_bytes: number of bytes to complete + * + * Description: + * Ends I/O on a number of bytes attached to @rq. + * If @rq has leftover, sets it up for the next range of segments. + * + * Return: + * 0 - we are done with this request + * 1 - still buffers pending for this request + **/ +int blk_end_request(struct request *rq, int error, int nr_bytes) +{ + return blk_end_io(rq, error, nr_bytes, 0, NULL); +} +EXPORT_SYMBOL_GPL(blk_end_request); + +/** + * __blk_end_request - Helper function for drivers to complete the request. + * @rq: the request being processed + * @error: 0 for success, < 0 for error + * @nr_bytes: number of bytes to complete + * + * Description: + * Must be called with queue lock held unlike blk_end_request(). + * + * Return: + * 0 - we are done with this request + * 1 - still buffers pending for this request + **/ +int __blk_end_request(struct request *rq, int error, int nr_bytes) +{ + if (blk_fs_request(rq) || blk_pc_request(rq)) { + if (__end_that_request_first(rq, error, nr_bytes)) + return 1; + } + + add_disk_randomness(rq->rq_disk); + + end_that_request_last(rq, error); + + return 0; +} +EXPORT_SYMBOL_GPL(__blk_end_request); + +/** + * blk_end_bidi_request - Helper function for drivers to complete bidi request. + * @rq: the bidi request being processed + * @error: 0 for success, < 0 for error + * @nr_bytes: number of bytes to complete @rq + * @bidi_bytes: number of bytes to complete @rq->next_rq + * + * Description: + * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. + * + * Return: + * 0 - we are done with this request + * 1 - still buffers pending for this request + **/ +int blk_end_bidi_request(struct request *rq, int error, int nr_bytes, + int bidi_bytes) +{ + return blk_end_io(rq, error, nr_bytes, bidi_bytes, NULL); +} +EXPORT_SYMBOL_GPL(blk_end_bidi_request); + +/** + * blk_end_request_callback - Special helper function for tricky drivers + * @rq: the request being processed + * @error: 0 for success, < 0 for error + * @nr_bytes: number of bytes to complete + * @drv_callback: function called between completion of bios in the request + * and completion of the request. + * If the callback returns non 0, this helper returns without + * completion of the request. + * + * Description: + * Ends I/O on a number of bytes attached to @rq. + * If @rq has leftover, sets it up for the next range of segments. + * + * This special helper function is used only for existing tricky drivers. + * (e.g. cdrom_newpc_intr() of ide-cd) + * This interface will be removed when such drivers are rewritten. + * Don't use this interface in other places anymore. + * + * Return: + * 0 - we are done with this request + * 1 - this request is not freed yet. + * this request still has pending buffers or + * the driver doesn't want to finish this request yet. + **/ +int blk_end_request_callback(struct request *rq, int error, int nr_bytes, + int (drv_callback)(struct request *)) +{ + return blk_end_io(rq, error, nr_bytes, 0, drv_callback); +} +EXPORT_SYMBOL_GPL(blk_end_request_callback); + static void blk_rq_bio_prep(struct request_queue *q, struct request *rq, struct bio *bio) { @@ -3853,55 +4030,100 @@ int __init blk_dev_init(void) return 0; } +static void cfq_dtor(struct io_context *ioc) +{ + struct cfq_io_context *cic[1]; + int r; + + /* + * We don't have a specific key to lookup with, so use the gang + * lookup to just retrieve the first item stored. The cfq exit + * function will iterate the full tree, so any member will do. + */ + r = radix_tree_gang_lookup(&ioc->radix_root, (void **) cic, 0, 1); + if (r > 0) + cic[0]->dtor(ioc); +} + /* - * IO Context helper functions + * IO Context helper functions. put_io_context() returns 1 if there are no + * more users of this io context, 0 otherwise. */ -void put_io_context(struct io_context *ioc) +int put_io_context(struct io_context *ioc) { if (ioc == NULL) - return; + return 1; BUG_ON(atomic_read(&ioc->refcount) == 0); if (atomic_dec_and_test(&ioc->refcount)) { - struct cfq_io_context *cic; - rcu_read_lock(); if (ioc->aic && ioc->aic->dtor) ioc->aic->dtor(ioc->aic); - if (ioc->cic_root.rb_node != NULL) { - struct rb_node *n = rb_first(&ioc->cic_root); - - cic = rb_entry(n, struct cfq_io_context, rb_node); - cic->dtor(ioc); - } rcu_read_unlock(); + cfq_dtor(ioc); kmem_cache_free(iocontext_cachep, ioc); + return 1; } + return 0; } EXPORT_SYMBOL(put_io_context); +static void cfq_exit(struct io_context *ioc) +{ + struct cfq_io_context *cic[1]; + int r; + + rcu_read_lock(); + /* + * See comment for cfq_dtor() + */ + r = radix_tree_gang_lookup(&ioc->radix_root, (void **) cic, 0, 1); + rcu_read_unlock(); + + if (r > 0) + cic[0]->exit(ioc); +} + /* Called by the exitting task */ void exit_io_context(void) { struct io_context *ioc; - struct cfq_io_context *cic; task_lock(current); ioc = current->io_context; current->io_context = NULL; task_unlock(current); - ioc->task = NULL; - if (ioc->aic && ioc->aic->exit) - ioc->aic->exit(ioc->aic); - if (ioc->cic_root.rb_node != NULL) { - cic = rb_entry(rb_first(&ioc->cic_root), struct cfq_io_context, rb_node); - cic->exit(ioc); + if (atomic_dec_and_test(&ioc->nr_tasks)) { + if (ioc->aic && ioc->aic->exit) + ioc->aic->exit(ioc->aic); + cfq_exit(ioc); + + put_io_context(ioc); } +} + +struct io_context *alloc_io_context(gfp_t gfp_flags, int node) +{ + struct io_context *ret; - put_io_context(ioc); + ret = kmem_cache_alloc_node(iocontext_cachep, gfp_flags, node); + if (ret) { + atomic_set(&ret->refcount, 1); + atomic_set(&ret->nr_tasks, 1); + spin_lock_init(&ret->lock); + ret->ioprio_changed = 0; + ret->ioprio = 0; + ret->last_waited = jiffies; /* doesn't matter... */ + ret->nr_batch_requests = 0; /* because this is 0 */ + ret->aic = NULL; + INIT_RADIX_TREE(&ret->radix_root, GFP_ATOMIC | __GFP_HIGH); + ret->ioc_data = NULL; + } + + return ret; } /* @@ -3921,16 +4143,8 @@ static struct io_context *current_io_context(gfp_t gfp_flags, int node) if (likely(ret)) return ret; - ret = kmem_cache_alloc_node(iocontext_cachep, gfp_flags, node); + ret = alloc_io_context(gfp_flags, node); if (ret) { - atomic_set(&ret->refcount, 1); - ret->task = current; - ret->ioprio_changed = 0; - ret->last_waited = jiffies; /* doesn't matter... */ - ret->nr_batch_requests = 0; /* because this is 0 */ - ret->aic = NULL; - ret->cic_root.rb_node = NULL; - ret->ioc_data = NULL; /* make sure set_task_ioprio() sees the settings above */ smp_wmb(); tsk->io_context = ret; @@ -3947,10 +4161,18 @@ static struct io_context *current_io_context(gfp_t gfp_flags, int node) */ struct io_context *get_io_context(gfp_t gfp_flags, int node) { - struct io_context *ret; - ret = current_io_context(gfp_flags, node); - if (likely(ret)) - atomic_inc(&ret->refcount); + struct io_context *ret = NULL; + + /* + * Check for unlikely race with exiting task. ioc ref count is + * zero when ioc is being detached. + */ + do { + ret = current_io_context(gfp_flags, node); + if (unlikely(!ret)) + break; + } while (!atomic_inc_not_zero(&ret->refcount)); + return ret; } EXPORT_SYMBOL(get_io_context); |