On 23/06/28 03:50PM, Damien Le Moal wrote:

On 6/28/23 03:36, Nitesh Shetty wrote:

quoted

For the devices which does not support copy, copy emulation is added.
It is required for in-kernel users like fabrics, where file descriptor is
not available and hence they can't use copy_file_range.
Copy-emulation is implemented by reading from source into memory and
writing to the corresponding destination asynchronously.
Also emulation is used, if copy offload fails or partially completes.

Signed-off-by: Nitesh Shetty <redacted>
Signed-off-by: Vincent Fu <redacted>
Signed-off-by: Anuj Gupta <redacted>
---
 block/blk-lib.c           | 183 +++++++++++++++++++++++++++++++++++++-
 block/blk-map.c           |   4 +-
 include/linux/blk_types.h |   5 ++
 include/linux/blkdev.h    |   3 +
 4 files changed, 192 insertions(+), 3 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 10c3eadd5bf6..09e0d5d51d03 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c

@@ -234,6 +234,180 @@ static ssize_t __blkdev_copy_offload(
 	return blkdev_copy_wait_io_completion(cio);
 }

+static void *blkdev_copy_alloc_buf(sector_t req_size, sector_t *alloc_size,
+		gfp_t gfp_mask)
+{
+	int min_size = PAGE_SIZE;
+	void *buf;
+
+	while (req_size >= min_size) {
+		buf = kvmalloc(req_size, gfp_mask);
+		if (buf) {
+			*alloc_size = req_size;
+			return buf;
+		}
+		/* retry half the requested size */

Kind of obvious :)

Acked. will remove.

quoted

+		req_size >>= 1;
+	}
+
+	return NULL;
+}
+
+static void blkdev_copy_emulate_write_endio(struct bio *bio)
+{
+	struct copy_ctx *ctx = bio->bi_private;
+	struct cio *cio = ctx->cio;
+	sector_t clen;
+
+	if (bio->bi_status) {
+		clen = (bio->bi_iter.bi_sector << SECTOR_SHIFT) - cio->pos_out;
+		cio->comp_len = min_t(sector_t, clen, cio->comp_len);
+	}
+	kfree(bvec_virt(&bio->bi_io_vec[0]));
+	bio_map_kern_endio(bio);
+	kfree(ctx);
+	if (atomic_dec_and_test(&cio->refcount)) {
+		if (cio->endio) {
+			cio->endio(cio->private, cio->comp_len);
+			kfree(cio);
+		} else
+			blk_wake_io_task(cio->waiter);

Curly brackets.

acked

quoted

+	}
+}
+
+static void blkdev_copy_emulate_read_endio(struct bio *read_bio)
+{
+	struct copy_ctx *ctx = read_bio->bi_private;
+	struct cio *cio = ctx->cio;
+	sector_t clen;
+
+	if (read_bio->bi_status) {
+		clen = (read_bio->bi_iter.bi_sector << SECTOR_SHIFT) -
+						cio->pos_in;
+		cio->comp_len = min_t(sector_t, clen, cio->comp_len);
+		kfree(bvec_virt(&read_bio->bi_io_vec[0]));
+		bio_map_kern_endio(read_bio);
+		kfree(ctx);
+
+		if (atomic_dec_and_test(&cio->refcount)) {
+			if (cio->endio) {
+				cio->endio(cio->private, cio->comp_len);
+				kfree(cio);
+			} else
+				blk_wake_io_task(cio->waiter);

Same.

acked

quoted

+		}
+	}
+	schedule_work(&ctx->dispatch_work);

ctx may have been freed above.

acked, will fix this.

quoted

+	kfree(read_bio);
+}
+
+static void blkdev_copy_dispatch_work(struct work_struct *work)
+{
+	struct copy_ctx *ctx = container_of(work, struct copy_ctx,
+			dispatch_work);

Please align the argument, or even better: split the line after "=".

acked.

Thank you
Nitesh Shetty