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Merge branch 'for-3.7/core' of git://git.kernel.dk/linux-block

Pull block IO update from Jens Axboe:
 "Core block IO bits for 3.7.  Not a huge round this time, it contains:

   - First series from Kent cleaning up and generalizing bio allocation
     and freeing.

   - WRITE_SAME support from Martin.

   - Mikulas patches to prevent O_DIRECT crashes when someone changes
     the block size of a device.

   - Make bio_split() work on data-less bio's (like trim/discards).

   - A few other minor fixups."

Fixed up silent semantic mis-merge as per Mikulas Patocka and Andrew
Morton.  It is due to the VM no longer using a prio-tree (see commit
6b2dbba: "mm: replace vma prio_tree with an interval tree").

So make set_blocksize() use mapping_mapped() instead of open-coding the
internal VM knowledge that has changed.

* 'for-3.7/core' of git://git.kernel.dk/linux-block: (26 commits)
  block: makes bio_split support bio without data
  scatterlist: refactor the sg_nents
  scatterlist: add sg_nents
  fs: fix include/percpu-rwsem.h export error
  percpu-rw-semaphore: fix documentation typos
  fs/block_dev.c:1644:5: sparse: symbol 'blkdev_mmap' was not declared
  blockdev: turn a rw semaphore into a percpu rw semaphore
  Fix a crash when block device is read and block size is changed at the same time
  block: fix request_queue->flags initialization
  block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue()
  block: ioctl to zero block ranges
  block: Make blkdev_issue_zeroout use WRITE SAME
  block: Implement support for WRITE SAME
  block: Consolidate command flag and queue limit checks for merges
  block: Clean up special command handling logic
  block/blk-tag.c: Remove useless kfree
  block: remove the duplicated setting for congestion_threshold
  block: reject invalid queue attribute values
  block: Add bio_clone_bioset(), bio_clone_kmalloc()
  block: Consolidate bio_alloc_bioset(), bio_kmalloc()
  ...
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torvalds committed Oct 11, 2012
2 parents ba0a5a3 + 02f3939 commit ce40be7a820bb393ac4ac69865f018d2f4038cf0
@@ -206,3 +206,17 @@ Description:
when a discarded area is read the discard_zeroes_data
parameter will be set to one. Otherwise it will be 0 and
the result of reading a discarded area is undefined.
+
+What: /sys/block/<disk>/queue/write_same_max_bytes
+Date: January 2012
+Contact: Martin K. Petersen <martin.petersen@oracle.com>
+Description:
+ Some devices support a write same operation in which a
+ single data block can be written to a range of several
+ contiguous blocks on storage. This can be used to wipe
+ areas on disk or to initialize drives in a RAID
+ configuration. write_same_max_bytes indicates how many
+ bytes can be written in a single write same command. If
+ write_same_max_bytes is 0, write same is not supported
+ by the device.
+
@@ -465,7 +465,6 @@ struct bio {
bio_end_io_t *bi_end_io; /* bi_end_io (bio) */
atomic_t bi_cnt; /* pin count: free when it hits zero */
void *bi_private;
- bio_destructor_t *bi_destructor; /* bi_destructor (bio) */
};
With this multipage bio design:
@@ -647,10 +646,6 @@ for a non-clone bio. There are the 6 pools setup for different size biovecs,
so bio_alloc(gfp_mask, nr_iovecs) will allocate a vec_list of the
given size from these slabs.
-The bi_destructor() routine takes into account the possibility of the bio
-having originated from a different source (see later discussions on
-n/w to block transfers and kvec_cb)
-
The bio_get() routine may be used to hold an extra reference on a bio prior
to i/o submission, if the bio fields are likely to be accessed after the
i/o is issued (since the bio may otherwise get freed in case i/o completion
@@ -0,0 +1,27 @@
+Percpu rw semaphores
+--------------------
+
+Percpu rw semaphores is a new read-write semaphore design that is
+optimized for locking for reading.
+
+The problem with traditional read-write semaphores is that when multiple
+cores take the lock for reading, the cache line containing the semaphore
+is bouncing between L1 caches of the cores, causing performance
+degradation.
+
+Locking for reading is very fast, it uses RCU and it avoids any atomic
+instruction in the lock and unlock path. On the other hand, locking for
+writing is very expensive, it calls synchronize_rcu() that can take
+hundreds of milliseconds.
+
+The lock is declared with "struct percpu_rw_semaphore" type.
+The lock is initialized percpu_init_rwsem, it returns 0 on success and
+-ENOMEM on allocation failure.
+The lock must be freed with percpu_free_rwsem to avoid memory leak.
+
+The lock is locked for read with percpu_down_read, percpu_up_read and
+for write with percpu_down_write, percpu_up_write.
+
+The idea of using RCU for optimized rw-lock was introduced by
+Eric Dumazet <eric.dumazet@gmail.com>.
+The code was written by Mikulas Patocka <mpatocka@redhat.com>
View
@@ -606,8 +606,8 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
/*
* A queue starts its life with bypass turned on to avoid
* unnecessary bypass on/off overhead and nasty surprises during
- * init. The initial bypass will be finished at the end of
- * blk_init_allocated_queue().
+ * init. The initial bypass will be finished when the queue is
+ * registered by blk_register_queue().
*/
q->bypass_depth = 1;
__set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
@@ -694,7 +694,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
q->request_fn = rfn;
q->prep_rq_fn = NULL;
q->unprep_rq_fn = NULL;
- q->queue_flags = QUEUE_FLAG_DEFAULT;
+ q->queue_flags |= QUEUE_FLAG_DEFAULT;
/* Override internal queue lock with supplied lock pointer */
if (lock)
@@ -710,11 +710,6 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
/* init elevator */
if (elevator_init(q, NULL))
return NULL;
-
- blk_queue_congestion_threshold(q);
-
- /* all done, end the initial bypass */
- blk_queue_bypass_end(q);
return q;
}
EXPORT_SYMBOL(blk_init_allocated_queue);
@@ -1657,8 +1652,8 @@ generic_make_request_checks(struct bio *bio)
goto end_io;
}
- if (unlikely(!(bio->bi_rw & REQ_DISCARD) &&
- nr_sectors > queue_max_hw_sectors(q))) {
+ if (likely(bio_is_rw(bio) &&
+ nr_sectors > queue_max_hw_sectors(q))) {
printk(KERN_ERR "bio too big device %s (%u > %u)\n",
bdevname(bio->bi_bdev, b),
bio_sectors(bio),
@@ -1699,8 +1694,12 @@ generic_make_request_checks(struct bio *bio)
if ((bio->bi_rw & REQ_DISCARD) &&
(!blk_queue_discard(q) ||
- ((bio->bi_rw & REQ_SECURE) &&
- !blk_queue_secdiscard(q)))) {
+ ((bio->bi_rw & REQ_SECURE) && !blk_queue_secdiscard(q)))) {
+ err = -EOPNOTSUPP;
+ goto end_io;
+ }
+
+ if (bio->bi_rw & REQ_WRITE_SAME && !bdev_write_same(bio->bi_bdev)) {
err = -EOPNOTSUPP;
goto end_io;
}
@@ -1810,15 +1809,20 @@ EXPORT_SYMBOL(generic_make_request);
*/
void submit_bio(int rw, struct bio *bio)
{
- int count = bio_sectors(bio);
-
bio->bi_rw |= rw;
/*
* If it's a regular read/write or a barrier with data attached,
* go through the normal accounting stuff before submission.
*/
- if (bio_has_data(bio) && !(rw & REQ_DISCARD)) {
+ if (bio_has_data(bio)) {
+ unsigned int count;
+
+ if (unlikely(rw & REQ_WRITE_SAME))
+ count = bdev_logical_block_size(bio->bi_bdev) >> 9;
+ else
+ count = bio_sectors(bio);
+
if (rw & WRITE) {
count_vm_events(PGPGOUT, count);
} else {
@@ -1864,11 +1868,10 @@ EXPORT_SYMBOL(submit_bio);
*/
int blk_rq_check_limits(struct request_queue *q, struct request *rq)
{
- if (rq->cmd_flags & REQ_DISCARD)
+ if (!rq_mergeable(rq))
return 0;
- if (blk_rq_sectors(rq) > queue_max_sectors(q) ||
- blk_rq_bytes(rq) > queue_max_hw_sectors(q) << 9) {
+ if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) {
printk(KERN_ERR "%s: over max size limit.\n", __func__);
return -EIO;
}
@@ -2340,7 +2343,7 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
req->buffer = bio_data(req->bio);
/* update sector only for requests with clear definition of sector */
- if (req->cmd_type == REQ_TYPE_FS || (req->cmd_flags & REQ_DISCARD))
+ if (req->cmd_type == REQ_TYPE_FS)
req->__sector += total_bytes >> 9;
/* mixed attributes always follow the first bio */
@@ -2781,16 +2784,10 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
blk_rq_init(NULL, rq);
__rq_for_each_bio(bio_src, rq_src) {
- bio = bio_alloc_bioset(gfp_mask, bio_src->bi_max_vecs, bs);
+ bio = bio_clone_bioset(bio_src, gfp_mask, bs);
if (!bio)
goto free_and_out;
- __bio_clone(bio, bio_src);
-
- if (bio_integrity(bio_src) &&
- bio_integrity_clone(bio, bio_src, gfp_mask, bs))
- goto free_and_out;
-
if (bio_ctr && bio_ctr(bio, bio_src, data))
goto free_and_out;
@@ -2807,7 +2804,7 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
free_and_out:
if (bio)
- bio_free(bio, bs);
+ bio_put(bio);
blk_rq_unprep_clone(rq);
return -ENOMEM;
View
@@ -129,6 +129,80 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
}
EXPORT_SYMBOL(blkdev_issue_discard);
+/**
+ * blkdev_issue_write_same - queue a write same operation
+ * @bdev: target blockdev
+ * @sector: start sector
+ * @nr_sects: number of sectors to write
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ * @page: page containing data to write
+ *
+ * Description:
+ * Issue a write same request for the sectors in question.
+ */
+int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask,
+ struct page *page)
+{
+ DECLARE_COMPLETION_ONSTACK(wait);
+ struct request_queue *q = bdev_get_queue(bdev);
+ unsigned int max_write_same_sectors;
+ struct bio_batch bb;
+ struct bio *bio;
+ int ret = 0;
+
+ if (!q)
+ return -ENXIO;
+
+ max_write_same_sectors = q->limits.max_write_same_sectors;
+
+ if (max_write_same_sectors == 0)
+ return -EOPNOTSUPP;
+
+ atomic_set(&bb.done, 1);
+ bb.flags = 1 << BIO_UPTODATE;
+ bb.wait = &wait;
+
+ while (nr_sects) {
+ bio = bio_alloc(gfp_mask, 1);
+ if (!bio) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ bio->bi_sector = sector;
+ bio->bi_end_io = bio_batch_end_io;
+ bio->bi_bdev = bdev;
+ bio->bi_private = &bb;
+ bio->bi_vcnt = 1;
+ bio->bi_io_vec->bv_page = page;
+ bio->bi_io_vec->bv_offset = 0;
+ bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
+
+ if (nr_sects > max_write_same_sectors) {
+ bio->bi_size = max_write_same_sectors << 9;
+ nr_sects -= max_write_same_sectors;
+ sector += max_write_same_sectors;
+ } else {
+ bio->bi_size = nr_sects << 9;
+ nr_sects = 0;
+ }
+
+ atomic_inc(&bb.done);
+ submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
+ }
+
+ /* Wait for bios in-flight */
+ if (!atomic_dec_and_test(&bb.done))
+ wait_for_completion(&wait);
+
+ if (!test_bit(BIO_UPTODATE, &bb.flags))
+ ret = -ENOTSUPP;
+
+ return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_write_same);
+
/**
* blkdev_issue_zeroout - generate number of zero filed write bios
* @bdev: blockdev to issue
@@ -140,7 +214,7 @@ EXPORT_SYMBOL(blkdev_issue_discard);
* Generate and issue number of bios with zerofiled pages.
*/
-int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask)
{
int ret;
@@ -190,4 +264,32 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
return ret;
}
+
+/**
+ * blkdev_issue_zeroout - zero-fill a block range
+ * @bdev: blockdev to write
+ * @sector: start sector
+ * @nr_sects: number of sectors to write
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ *
+ * Description:
+ * Generate and issue number of bios with zerofiled pages.
+ */
+
+int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask)
+{
+ if (bdev_write_same(bdev)) {
+ unsigned char bdn[BDEVNAME_SIZE];
+
+ if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
+ ZERO_PAGE(0)))
+ return 0;
+
+ bdevname(bdev, bdn);
+ pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
+ }
+
+ return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
+}
EXPORT_SYMBOL(blkdev_issue_zeroout);
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