Re: [PATCH v20 02/12] Add infrastructure for copy offload in block and request layer.
From: Bart Van Assche <bvanassche@acm.org>
Date: 2024-05-20 23:00:54
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Possibly related (same subject, not in this thread)
- 2024-06-28 · Re: [PATCH v20 02/12] Add infrastructure for copy offload in block and request layer. · Bart Van Assche <bvanassche@acm.org>
- 2024-06-26 · Re: [PATCH v20 02/12] Add infrastructure for copy offload in block and request layer. · Christoph Hellwig <hch@lst.de>
- 2024-06-25 · Re: [PATCH v20 02/12] Add infrastructure for copy offload in block and request layer. · Damien Le Moal <dlemoal@kernel.org>
- 2024-06-25 · Re: [PATCH v20 02/12] Add infrastructure for copy offload in block and request layer. · Bart Van Assche <bvanassche@acm.org>
- 2024-06-24 · Re: [PATCH v20 02/12] Add infrastructure for copy offload in block and request layer. · Keith Busch <kbusch@kernel.org>
On 5/20/24 03:20, Nitesh Shetty wrote:
Upon arrival of source bio we merge these two bio's and send corresponding request down to device driver.
bios with different operation types must not be merged.
+static enum bio_merge_status bio_attempt_copy_offload_merge(struct request *req,
+ struct bio *bio)
+{
+ if (req->__data_len != bio->bi_iter.bi_size)
+ return BIO_MERGE_FAILED;
+
+ req->biotail->bi_next = bio;
+ req->biotail = bio;
+ req->nr_phys_segments++;
+ req->__data_len += bio->bi_iter.bi_size;
+
+ return BIO_MERGE_OK;
+}This function appends a bio to a request. Hence, the name of this function is wrong.
quoted hunk ↗ jump to hunk
@@ -1085,6 +1124,8 @@ static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q, break; case ELEVATOR_DISCARD_MERGE: return bio_attempt_discard_merge(q, rq, bio); + case ELEVATOR_COPY_OFFLOAD_MERGE: + return bio_attempt_copy_offload_merge(rq, bio); default: return BIO_MERGE_NONE; }
Is any code added in this patch series that causes an I/O scheduler to return ELEVATOR_COPY_OFFLOAD_MERGE?
+static inline bool blk_copy_offload_mergable(struct request *req,
+ struct bio *bio)
+{
+ return (req_op(req) == REQ_OP_COPY_DST &&
+ bio_op(bio) == REQ_OP_COPY_SRC);
+}bios with different operation types must not be merged. Please rename this function.
+static inline bool op_is_copy(blk_opf_t op)
+{
+ return ((op & REQ_OP_MASK) == REQ_OP_COPY_SRC ||
+ (op & REQ_OP_MASK) == REQ_OP_COPY_DST);
+}The above function is not used in this patch. Please introduce new functions in the patch in which these are used for the first time. Thanks, Bart.