[PATCH 06/12] block: move request based cloning helpers to blk-mq.c

Christoph Hellwig
2021-10-25T07:05:43Z

Keep all the request based code together.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-core.c | 184 +----------------------------------------------
block/blk-mq.c | 175 +++++++++++++++++++++++++++++++++++++++++++-
block/blk-mq.h | 3 -
block/blk.h | 10 +++
4 files changed, 185 insertions(+), 187 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 08c6077365ac9..8ae6ba9ec1050 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -618,7 +618,7 @@ static int __init setup_fail_make_request(char *str)
}
__setup("fail_make_request=", setup_fail_make_request);

-static bool should_fail_request(struct block_device *part, unsigned int bytes)
+bool should_fail_request(struct block_device *part, unsigned int bytes)
{
return part->bd_make_it_fail && should_fail(&fail_make_request, bytes);
}
@@ -632,15 +632,6 @@ static int __init fail_make_request_debugfs(void)
}

late_initcall(fail_make_request_debugfs);
-
-#else /* CONFIG_FAIL_MAKE_REQUEST */
-
-static inline bool should_fail_request(struct block_device *part,
- unsigned int bytes)
-{
- return false;
-}
-
#endif /* CONFIG_FAIL_MAKE_REQUEST */

static inline bool bio_check_ro(struct bio *bio)
@@ -1114,92 +1105,6 @@ int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob,
}
EXPORT_SYMBOL_GPL(iocb_bio_iopoll);

-/**
- * blk_cloned_rq_check_limits - Helper function to check a cloned request
- * for the new queue limits
- * @q: the queue
- * @rq: the request being checked
- *
- * Description:
- * @rq may have been made based on weaker limitations of upper-level queues
- * in request stacking drivers, and it may violate the limitation of @q.
- * Since the block layer and the underlying device driver trust @rq
- * after it is inserted to @q, it should be checked against @q before
- * the insertion using this generic function.
- *
- * Request stacking drivers like request-based dm may change the queue
- * limits when retrying requests on other queues. Those requests need
- * to be checked against the new queue limits again during dispatch.
- */
-static blk_status_t blk_cloned_rq_check_limits(struct request_queue *q,
- struct request *rq)
-{
- unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
-
- if (blk_rq_sectors(rq) > max_sectors) {
- /*
- * SCSI device does not have a good way to return if
- * Write Same/Zero is actually supported. If a device rejects
- * a non-read/write command (discard, write same,etc.) the
- * low-level device driver will set the relevant queue limit to
- * 0 to prevent blk-lib from issuing more of the offending
- * operations. Commands queued prior to the queue limit being
- * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
- * errors being propagated to upper layers.
- */
- if (max_sectors == 0)
- return BLK_STS_NOTSUPP;
-
- printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
- __func__, blk_rq_sectors(rq), max_sectors);
- return BLK_STS_IOERR;
- }
-
- /*
- * The queue settings related to segment counting may differ from the
- * original queue.
- */
- rq->nr_phys_segments = blk_recalc_rq_segments(rq);
- if (rq->nr_phys_segments > queue_max_segments(q)) {
- printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n",
- __func__, rq->nr_phys_segments, queue_max_segments(q));
- return BLK_STS_IOERR;
- }
-
- return BLK_STS_OK;
-}
-
-/**
- * blk_insert_cloned_request - Helper for stacking drivers to submit a request
- * @q: the queue to submit the request
- * @rq: the request being queued
- */
-blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq)
-{
- blk_status_t ret;
-
- ret = blk_cloned_rq_check_limits(q, rq);
- if (ret != BLK_STS_OK)
- return ret;
-
- if (rq->rq_disk &&
- should_fail_request(rq->rq_disk->part0, blk_rq_bytes(rq)))
- return BLK_STS_IOERR;
-
- if (blk_crypto_insert_cloned_request(rq))
- return BLK_STS_IOERR;
-
- blk_account_io_start(rq);
-
- /*
- * Since we have a scheduler attached on the top device,
- * bypass a potential scheduler on the bottom device for
- * insert.
- */
- return blk_mq_request_issue_directly(rq, true);
-}
-EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
-
static void update_io_ticks(struct block_device *part, unsigned long now,
bool end)
{
@@ -1352,93 +1257,6 @@ int blk_lld_busy(struct request_queue *q)
}
EXPORT_SYMBOL_GPL(blk_lld_busy);

-/**
- * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
- * @rq: the clone request to be cleaned up
- *
- * Description:
- * Free all bios in @rq for a cloned request.
- */
-void blk_rq_unprep_clone(struct request *rq)
-{
- struct bio *bio;
-
- while ((bio = rq->bio) != NULL) {
- rq->bio = bio->bi_next;
-
- bio_put(bio);
- }
-}
-EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
-
-/**
- * blk_rq_prep_clone - Helper function to setup clone request
- * @rq: the request to be setup
- * @rq_src: original request to be cloned
- * @bs: bio_set that bios for clone are allocated from
- * @gfp_mask: memory allocation mask for bio
- * @bio_ctr: setup function to be called for each clone bio.
- * Returns %0 for success, non %0 for failure.
- * @data: private data to be passed to @bio_ctr
- *
- * Description:
- * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
- * Also, pages which the original bios are pointing to are not copied
- * and the cloned bios just point same pages.
- * So cloned bios must be completed before original bios, which means
- * the caller must complete @rq before @rq_src.
- */
-int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
- struct bio_set *bs, gfp_t gfp_mask,
- int (*bio_ctr)(struct bio *, struct bio *, void *),
- void *data)
-{
- struct bio *bio, *bio_src;
-
- if (!bs)
- bs = &fs_bio_set;
-
- __rq_for_each_bio(bio_src, rq_src) {
- bio = bio_clone_fast(bio_src, gfp_mask, bs);
- if (!bio)
- goto free_and_out;
-
- if (bio_ctr && bio_ctr(bio, bio_src, data))
- goto free_and_out;
-
- if (rq->bio) {
- rq->biotail->bi_next = bio;
- rq->biotail = bio;
- } else {
- rq->bio = rq->biotail = bio;
- }
- bio = NULL;
- }
-
- /* Copy attributes of the original request to the clone request. */
- rq->__sector = blk_rq_pos(rq_src);
- rq->__data_len = blk_rq_bytes(rq_src);
- if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
- rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
- rq->special_vec = rq_src->special_vec;
- }
- rq->nr_phys_segments = rq_src->nr_phys_segments;
- rq->ioprio = rq_src->ioprio;
-
- if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
- goto free_and_out;
-
- return 0;
-
-free_and_out:
- if (bio)
- bio_put(bio);
- blk_rq_unprep_clone(rq);
-
- return -ENOMEM;
-}
-EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
-
int kblockd_schedule_work(struct work_struct *work)
{
return queue_work(kblockd_workqueue, work);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f46d41a760106..923231023fe84 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2403,7 +2403,7 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
hctx_unlock(hctx, srcu_idx);
}

-blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
+static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
{
blk_status_t ret;
int srcu_idx;
@@ -2720,6 +2720,179 @@ void blk_mq_submit_bio(struct bio *bio)
blk_queue_exit(q);
}

+/**
+ * blk_cloned_rq_check_limits - Helper function to check a cloned request
+ * for the new queue limits
+ * @q: the queue
+ * @rq: the request being checked
+ *
+ * Description:
+ * @rq may have been made based on weaker limitations of upper-level queues
+ * in request stacking drivers, and it may violate the limitation of @q.
+ * Since the block layer and the underlying device driver trust @rq
+ * after it is inserted to @q, it should be checked against @q before
+ * the insertion using this generic function.
+ *
+ * Request stacking drivers like request-based dm may change the queue
+ * limits when retrying requests on other queues. Those requests need
+ * to be checked against the new queue limits again during dispatch.
+ */
+static blk_status_t blk_cloned_rq_check_limits(struct request_queue *q,
+ struct request *rq)
+{
+ unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
+
+ if (blk_rq_sectors(rq) > max_sectors) {
+ /*
+ * SCSI device does not have a good way to return if
+ * Write Same/Zero is actually supported. If a device rejects
+ * a non-read/write command (discard, write same,etc.) the
+ * low-level device driver will set the relevant queue limit to
+ * 0 to prevent blk-lib from issuing more of the offending
+ * operations. Commands queued prior to the queue limit being
+ * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
+ * errors being propagated to upper layers.
+ */
+ if (max_sectors == 0)
+ return BLK_STS_NOTSUPP;
+
+ printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
+ __func__, blk_rq_sectors(rq), max_sectors);
+ return BLK_STS_IOERR;
+ }
+
+ /*
+ * The queue settings related to segment counting may differ from the
+ * original queue.
+ */
+ rq->nr_phys_segments = blk_recalc_rq_segments(rq);
+ if (rq->nr_phys_segments > queue_max_segments(q)) {
+ printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n",
+ __func__, rq->nr_phys_segments, queue_max_segments(q));
+ return BLK_STS_IOERR;
+ }
+
+ return BLK_STS_OK;
+}
+
+/**
+ * blk_insert_cloned_request - Helper for stacking drivers to submit a request
+ * @q: the queue to submit the request
+ * @rq: the request being queued
+ */
+blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq)
+{
+ blk_status_t ret;
+
+ ret = blk_cloned_rq_check_limits(q, rq);
+ if (ret != BLK_STS_OK)
+ return ret;
+
+ if (rq->rq_disk &&
+ should_fail_request(rq->rq_disk->part0, blk_rq_bytes(rq)))
+ return BLK_STS_IOERR;
+
+ if (blk_crypto_insert_cloned_request(rq))
+ return BLK_STS_IOERR;
+
+ blk_account_io_start(rq);
+
+ /*
+ * Since we have a scheduler attached on the top device,
+ * bypass a potential scheduler on the bottom device for
+ * insert.
+ */
+ return blk_mq_request_issue_directly(rq, true);
+}
+EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
+
+/**
+ * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
+ * @rq: the clone request to be cleaned up
+ *
+ * Description:
+ * Free all bios in @rq for a cloned request.
+ */
+void blk_rq_unprep_clone(struct request *rq)
+{
+ struct bio *bio;
+
+ while ((bio = rq->bio) != NULL) {
+ rq->bio = bio->bi_next;
+
+ bio_put(bio);
+ }
+}
+EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
+
+/**
+ * blk_rq_prep_clone - Helper function to setup clone request
+ * @rq: the request to be setup
+ * @rq_src: original request to be cloned
+ * @bs: bio_set that bios for clone are allocated from
+ * @gfp_mask: memory allocation mask for bio
+ * @bio_ctr: setup function to be called for each clone bio.
+ * Returns %0 for success, non %0 for failure.
+ * @data: private data to be passed to @bio_ctr
+ *
+ * Description:
+ * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
+ * Also, pages which the original bios are pointing to are not copied
+ * and the cloned bios just point same pages.
+ * So cloned bios must be completed before original bios, which means
+ * the caller must complete @rq before @rq_src.
+ */
+int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
+ struct bio_set *bs, gfp_t gfp_mask,
+ int (*bio_ctr)(struct bio *, struct bio *, void *),
+ void *data)
+{
+ struct bio *bio, *bio_src;
+
+ if (!bs)
+ bs = &fs_bio_set;
+
+ __rq_for_each_bio(bio_src, rq_src) {
+ bio = bio_clone_fast(bio_src, gfp_mask, bs);
+ if (!bio)
+ goto free_and_out;
+
+ if (bio_ctr && bio_ctr(bio, bio_src, data))
+ goto free_and_out;
+
+ if (rq->bio) {
+ rq->biotail->bi_next = bio;
+ rq->biotail = bio;
+ } else {
+ rq->bio = rq->biotail = bio;
+ }
+ bio = NULL;
+ }
+
+ /* Copy attributes of the original request to the clone request. */
+ rq->__sector = blk_rq_pos(rq_src);
+ rq->__data_len = blk_rq_bytes(rq_src);
+ if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
+ rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
+ rq->special_vec = rq_src->special_vec;
+ }
+ rq->nr_phys_segments = rq_src->nr_phys_segments;
+ rq->ioprio = rq_src->ioprio;
+
+ if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
+ goto free_and_out;
+
+ return 0;
+
+free_and_out:
+ if (bio)
+ bio_put(bio);
+ blk_rq_unprep_clone(rq);
+
+ return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
+
static size_t order_to_size(unsigned int order)
{
return (size_t)PAGE_SIZE << order;
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 08fb5922e611b..6e25303dbebe8 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -65,9 +65,6 @@ void blk_mq_request_bypass_insert(struct request *rq, bool at_head,
bool run_queue);
void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
struct list_head *list);
-
-/* Used by blk_insert_cloned_request() to issue request directly */
-blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last);
void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
struct list_head *list);

diff --git a/block/blk.h b/block/blk.h
index 6a039e6c7d077..c5fc3f97d1e5a 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -454,4 +454,14 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg);

extern const struct address_space_operations def_blk_aops;

+#ifdef CONFIG_FAIL_MAKE_REQUEST
+bool should_fail_request(struct block_device *part, unsigned int bytes);
+#else /* CONFIG_FAIL_MAKE_REQUEST */
+static inline bool should_fail_request(struct block_device *part,
+ unsigned int bytes)
+{
+ return false;
+}
+#endif /* CONFIG_FAIL_MAKE_REQUEST */
+
#endif /* BLK_INTERNAL_H */
--
2.30.2