bdev/part: Modify spdk_bdev_part_submit_request() to use custom completion callback

In the following patches, we will add a feature to inject data
corruption to the error bdev module. For read I/O, we will have
to inject data corruption at completion. However, if we use
spdk_bdev_part_submit_request(), it will not be possible because we
cannot add any custom operation into the completion callback.
To fix the issue, modify spdk_+bdev_part_submit_request() and
rename it to spdk_bdev_part_submit_request_ext().
Fortunately, we can use stored_user_cb in struct spdk_bdev_io.

Signed-off-by: Shuhei Matsumoto <smatsumoto@nvidia.com>
Change-Id: I46d3c40ea88a3fedd8a8fef6b68ee417c814a7a1
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/15002
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@nvidia.com>

CHANGELOG.md

@@ -8,6 +8,8 @@ Both of interleaved and separated metadata are now supported by the malloc bdev
 
 Protection information is now supported by the malloc bdev module.
 
+A new API `spkd_bdev_part_submit_request_ext` was added to specify a custom completion callback.
+
 ### scheduler
 
 Changing scheduler from dynamic back to static is no longer possible,

include/spdk/bdev_module.h

@@ -1287,6 +1287,25 @@ int spdk_bdev_part_construct(struct spdk_bdev_part *part, struct spdk_bdev_part_
  */
 int spdk_bdev_part_submit_request(struct spdk_bdev_part_channel *ch, struct spdk_bdev_io *bdev_io);
 
+/**
+ * Forwards I/O from an spdk_bdev_part to the underlying base bdev.
+ *
+ * This function will apply the offset_blocks the user provided to
+ * spdk_bdev_part_construct to the I/O. The user should not manually
+ * apply this offset before submitting any I/O through this function.
+ *
+ * This function enables user to specify a completion callback. It is required that
+ * the completion callback calls spdk_bdev_io_complete() for the forwarded I/O.
+ *
+ * \param ch The I/O channel associated with the spdk_bdev_part.
+ * \param bdev_io The I/O to be submitted to the underlying bdev.
+ * \param cb Called when the forwarded I/O completes.
+ * \return 0 on success or non-zero if submit request failed.
+ */
+int spdk_bdev_part_submit_request_ext(struct spdk_bdev_part_channel *ch,
+				      struct spdk_bdev_io *bdev_io,
+				      spdk_bdev_io_completion_cb cb);
+
 /**
  * Return a pointer to this part's spdk_bdev.
  *

lib/bdev/part.c

@@ -238,6 +238,7 @@ bdev_part_complete_io(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
 {
 	struct spdk_bdev_io *part_io = cb_arg;
 	uint32_t offset, remapped_offset;
+	spdk_bdev_io_completion_cb cb;
 	int rc, status;
 
 	switch (bdev_io->type) {
@@ -260,14 +261,22 @@ bdev_part_complete_io(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
 		break;
 	}
 
-	status = success ? SPDK_BDEV_IO_STATUS_SUCCESS : SPDK_BDEV_IO_STATUS_FAILED;
 
-	spdk_bdev_io_complete(part_io, status);
+	cb = part_io->u.bdev.stored_user_cb;
+	if (cb != NULL) {
+		cb(part_io, success, NULL);
+	} else {
+		status = success ? SPDK_BDEV_IO_STATUS_SUCCESS : SPDK_BDEV_IO_STATUS_FAILED;
+
+		spdk_bdev_io_complete(part_io, status);
+	}
+
 	spdk_bdev_free_io(bdev_io);
 }
 
 int
-spdk_bdev_part_submit_request(struct spdk_bdev_part_channel *ch, struct spdk_bdev_io *bdev_io)
+spdk_bdev_part_submit_request_ext(struct spdk_bdev_part_channel *ch, struct spdk_bdev_io *bdev_io,
+				  spdk_bdev_io_completion_cb cb)
 {
 	struct spdk_bdev_part *part = ch->part;
 	struct spdk_io_channel *base_ch = ch->base_ch;
@@ -275,6 +284,8 @@ spdk_bdev_part_submit_request(struct spdk_bdev_part_channel *ch, struct spdk_bde
 	uint64_t offset, remapped_offset, remapped_src_offset;
 	int rc = 0;
 
+	bdev_io->u.bdev.stored_user_cb = cb;
+
 	offset = bdev_io->u.bdev.offset_blocks;
 	remapped_offset = offset + part->internal.offset_blocks;
 
@@ -382,6 +393,12 @@ spdk_bdev_part_submit_request(struct spdk_bdev_part_channel *ch, struct spdk_bde
 	return rc;
 }
 
+int
+spdk_bdev_part_submit_request(struct spdk_bdev_part_channel *ch, struct spdk_bdev_io *bdev_io)
+{
+	return spdk_bdev_part_submit_request_ext(ch, bdev_io, NULL);
+}
+
 static int
 bdev_part_channel_create_cb(void *io_device, void *ctx_buf)
 {

lib/bdev/spdk_bdev.map

@@ -149,6 +149,7 @@
 	spdk_bdev_part_base_construct_ext;
 	spdk_bdev_part_construct;
 	spdk_bdev_part_submit_request;
+	spdk_bdev_part_submit_request_ext;
 	spdk_bdev_part_get_bdev;
 	spdk_bdev_part_get_base;
 	spdk_bdev_part_get_base_bdev;