accel: expose method for allocating accel buffers

This will allow a platform driver to allocate a buffer in case it cannot
execute the whole sequence and the destination buffer of the last
operation is a "virtual" accel buffer.

Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
Change-Id: Ia947cf553619828a170c5d0563b4c355d7b5ead5
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/16377
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@nvidia.com>

include/spdk_internal/accel_module.h

@@ -217,4 +217,23 @@ static void __attribute__((constructor)) _spdk_accel_driver_register_##name(void
  */
 struct spdk_memory_domain *spdk_accel_get_memory_domain(void);
 
+typedef void (*spdk_accel_sequence_get_buf_cb)(struct spdk_accel_sequence *seq, void *cb_arg);
+
+/**
+ * Allocates memory for an accel buffer in a given sequence.  The callback is only executed if the
+ * buffer couldn't be allocated immediately.
+ *
+ * \param seq Sequence object.
+ * \param buf Accel buffer to allocate.
+ * \param domain Accel memory domain.
+ * \param domain_ctx Memory domain context.
+ * \param cb_fn Callback to be executed once the buffer is allocated.
+ * \param cb_ctx Argument to be passed to `cb_fn`.
+ *
+ * \return true if the buffer was immediately allocated, false otherwise.
+ */
+bool spdk_accel_alloc_sequence_buf(struct spdk_accel_sequence *seq, void *buf,
+				   struct spdk_memory_domain *domain, void *domain_ctx,
+				   spdk_accel_sequence_get_buf_cb cb_fn, void *cb_ctx);
+
 #endif

lib/accel/accel.c

@@ -114,6 +114,8 @@ struct accel_buffer {
 	void				*buf;
 	uint64_t			len;
 	struct spdk_iobuf_entry		iobuf;
+	spdk_accel_sequence_get_buf_cb	cb_fn;
+	void				*cb_ctx;
 	TAILQ_ENTRY(accel_buffer)	link;
 };
 
@@ -706,6 +708,7 @@ accel_get_buf(struct accel_io_channel *ch, uint64_t len)
 	buf->len = len;
 	buf->buf = NULL;
 	buf->seq = NULL;
+	buf->cb_fn = NULL;
 
 	return buf;
 }
@@ -1215,6 +1218,41 @@ accel_sequence_check_virtbuf(struct spdk_accel_sequence *seq, struct spdk_accel_
 	return true;
 }
 
+static void
+accel_sequence_get_buf_cb(struct spdk_iobuf_entry *entry, void *buf)
+{
+	struct accel_buffer *accel_buf;
+
+	accel_buf = SPDK_CONTAINEROF(entry, struct accel_buffer, iobuf);
+
+	assert(accel_buf->seq != NULL);
+	assert(accel_buf->buf == NULL);
+	accel_buf->buf = buf;
+
+	accel_sequence_set_virtbuf(accel_buf->seq, accel_buf);
+	accel_buf->cb_fn(accel_buf->seq, accel_buf->cb_ctx);
+}
+
+bool
+spdk_accel_alloc_sequence_buf(struct spdk_accel_sequence *seq, void *buf,
+			      struct spdk_memory_domain *domain, void *domain_ctx,
+			      spdk_accel_sequence_get_buf_cb cb_fn, void *cb_ctx)
+{
+	struct accel_buffer *accel_buf = domain_ctx;
+
+	assert(domain == g_accel_domain);
+	accel_buf->cb_fn = cb_fn;
+	accel_buf->cb_ctx = cb_ctx;
+
+	if (!accel_sequence_alloc_buf(seq, accel_buf, accel_sequence_get_buf_cb)) {
+		return false;
+	}
+
+	accel_sequence_set_virtbuf(seq, accel_buf);
+
+	return true;
+}
+
 static inline uint64_t
 accel_get_iovlen(struct iovec *iovs, uint32_t iovcnt)
 {

lib/accel/spdk_accel.map

@@ -42,6 +42,7 @@
 	spdk_accel_sequence_continue;
 	spdk_accel_driver_register;
 	spdk_accel_get_memory_domain;
+	spdk_accel_alloc_sequence_buf;
 
 	local: *;
 };