Now, released hyper_dmabuf_ids are stored in a stack - (hyper_dmabuf_private.id_queue) for reuse. This is to prevent overflow of ids for buffers. We also limit maximum number for the id to 1000 for the stability and optimal performance.
Signed-off-by: Dongwon Kim dongwon.kim@intel.com --- drivers/xen/hyper_dmabuf/Makefile | 1 + drivers/xen/hyper_dmabuf/hyper_dmabuf_drv.c | 5 ++ drivers/xen/hyper_dmabuf/hyper_dmabuf_drv.h | 6 ++ drivers/xen/hyper_dmabuf/hyper_dmabuf_id.c | 76 ++++++++++++++++++++++ drivers/xen/hyper_dmabuf/hyper_dmabuf_id.h | 24 +++++++ drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c | 1 + drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c | 15 ++--- .../xen/hyper_dmabuf/hyper_dmabuf_remote_sync.c | 3 + drivers/xen/hyper_dmabuf/hyper_dmabuf_struct.h | 9 --- 9 files changed, 120 insertions(+), 20 deletions(-) create mode 100644 drivers/xen/hyper_dmabuf/hyper_dmabuf_id.c create mode 100644 drivers/xen/hyper_dmabuf/hyper_dmabuf_id.h
diff --git a/drivers/xen/hyper_dmabuf/Makefile b/drivers/xen/hyper_dmabuf/Makefile index 3459382..c9b8b7f 100644 --- a/drivers/xen/hyper_dmabuf/Makefile +++ b/drivers/xen/hyper_dmabuf/Makefile @@ -7,6 +7,7 @@ ifneq ($(KERNELRELEASE),) hyper_dmabuf_list.o \ hyper_dmabuf_imp.o \ hyper_dmabuf_msg.o \ + hyper_dmabuf_id.o \ hyper_dmabuf_remote_sync.o \ xen/hyper_dmabuf_xen_comm.o \ xen/hyper_dmabuf_xen_comm_list.o diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_drv.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_drv.c index 5a7cfa5..66d6cb9 100644 --- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_drv.c +++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_drv.c @@ -5,6 +5,7 @@ #include "hyper_dmabuf_drv.h" #include "hyper_dmabuf_conf.h" #include "hyper_dmabuf_list.h" +#include "hyper_dmabuf_id.h" #include "xen/hyper_dmabuf_xen_comm_list.h" #include "xen/hyper_dmabuf_xen_comm.h"
@@ -67,6 +68,10 @@ static void hyper_dmabuf_drv_exit(void) if (hyper_dmabuf_private.work_queue) destroy_workqueue(hyper_dmabuf_private.work_queue);
+ /* destroy id_queue */ + if (hyper_dmabuf_private.id_queue) + destroy_reusable_list(); + hyper_dmabuf_destroy_data_dir(); printk( KERN_NOTICE "dma_buf-src_sink model: Exiting" ); unregister_device(); diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_drv.h b/drivers/xen/hyper_dmabuf/hyper_dmabuf_drv.h index ff883e1..37b0cc1 100644 --- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_drv.h +++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_drv.h @@ -1,10 +1,16 @@ #ifndef __LINUX_PUBLIC_HYPER_DMABUF_DRV_H__ #define __LINUX_PUBLIC_HYPER_DMABUF_DRV_H__
+struct list_reusable_id { + int id; + struct list_head list; +}; + struct hyper_dmabuf_private { struct device *device; int domid; struct workqueue_struct *work_queue; + struct list_reusable_id *id_queue; };
typedef int (*hyper_dmabuf_ioctl_t)(void *data); diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_id.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_id.c new file mode 100644 index 0000000..7bbb179 --- /dev/null +++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_id.c @@ -0,0 +1,76 @@ +#include <linux/list.h> +#include <linux/slab.h> +#include "hyper_dmabuf_drv.h" +#include "hyper_dmabuf_id.h" + +extern struct hyper_dmabuf_private hyper_dmabuf_private; + +void store_reusable_id(int id) +{ + struct list_reusable_id *reusable_head = hyper_dmabuf_private.id_queue; + struct list_reusable_id *new_reusable; + + new_reusable = kmalloc(sizeof(*new_reusable), GFP_KERNEL); + new_reusable->id = id; + + list_add(&new_reusable->list, &reusable_head->list); +} + +static int retrieve_reusable_id(void) +{ + struct list_reusable_id *reusable_head = hyper_dmabuf_private.id_queue; + + /* check there is reusable id */ + if (!list_empty(&reusable_head->list)) { + reusable_head = list_first_entry(&reusable_head->list, + struct list_reusable_id, + list); + + list_del(&reusable_head->list); + return reusable_head->id; + } + + return -1; +} + +void destroy_reusable_list(void) +{ + struct list_reusable_id *reusable_head = hyper_dmabuf_private.id_queue; + struct list_reusable_id *temp_head; + + if (reusable_head) { + /* freeing mem space all reusable ids in the stack */ + while (!list_empty(&reusable_head->list)) { + temp_head = list_first_entry(&reusable_head->list, + struct list_reusable_id, + list); + list_del(&temp_head->list); + kfree(temp_head); + } + + /* freeing head */ + kfree(reusable_head); + } +} + +int hyper_dmabuf_get_id(void) +{ + static int id = 0; + struct list_reusable_id *reusable_head; + int ret; + + /* first cla to hyper_dmabuf_get_id */ + if (id == 0) { + reusable_head = kmalloc(sizeof(*reusable_head), GFP_KERNEL); + reusable_head->id = -1; /* list head have invalid id */ + INIT_LIST_HEAD(&reusable_head->list); + hyper_dmabuf_private.id_queue = reusable_head; + } + + ret = retrieve_reusable_id(); + + if (ret < 0 && id < HYPER_DMABUF_ID_MAX) + return HYPER_DMABUF_ID_CREATE(hyper_dmabuf_private.domid, id++); + + return ret; +} diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_id.h b/drivers/xen/hyper_dmabuf/hyper_dmabuf_id.h new file mode 100644 index 0000000..2c8daf3 --- /dev/null +++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_id.h @@ -0,0 +1,24 @@ +#ifndef __HYPER_DMABUF_ID_H__ +#define __HYPER_DMABUF_ID_H__ + +/* Importer combine source domain id with given hyper_dmabuf_id + * to make it unique in case there are multiple exporters */ + +#define HYPER_DMABUF_ID_CREATE(domid, id) \ + ((((domid) & 0xFF) << 24) | ((id) & 0xFFFFFF)) + +#define HYPER_DMABUF_DOM_ID(id) \ + (((id) >> 24) & 0xFF) + +/* currently maximum number of buffers shared + * at any given moment is limited to 1000 + */ +#define HYPER_DMABUF_ID_MAX 1000 + +void store_reusable_id(int id); + +void destroy_reusable_list(void); + +int hyper_dmabuf_get_id(void); + +#endif /*__HYPER_DMABUF_ID_H*/ diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c index fa445e5..b109138 100644 --- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c +++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_imp.c @@ -7,6 +7,7 @@ #include <asm/xen/page.h> #include "hyper_dmabuf_struct.h" #include "hyper_dmabuf_imp.h" +#include "hyper_dmabuf_id.h" #include "xen/hyper_dmabuf_xen_comm.h" #include "hyper_dmabuf_msg.h" #include "hyper_dmabuf_list.h" diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c index e334b77..5c6d9c8 100644 --- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c +++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c @@ -11,6 +11,7 @@ #include "hyper_dmabuf_imp.h" #include "hyper_dmabuf_list.h" #include "hyper_dmabuf_drv.h" +#include "hyper_dmabuf_id.h" #include "hyper_dmabuf_query.h" #include "xen/hyper_dmabuf_xen_comm.h" #include "xen/hyper_dmabuf_xen_comm_list.h" @@ -18,16 +19,6 @@
extern struct hyper_dmabuf_private hyper_dmabuf_private;
-static uint32_t hyper_dmabuf_id_gen(void) { - /* TODO: add proper implementation */ - static uint32_t id = 1000; - static int32_t domid = -1; - if (domid == -1) { - domid = hyper_dmabuf_get_domid(); - } - return HYPER_DMABUF_ID_IMPORTER(domid, id++); -} - static int hyper_dmabuf_exporter_ring_setup(void *data) { struct ioctl_hyper_dmabuf_exporter_ring_setup *ring_attr; @@ -133,7 +124,7 @@ static int hyper_dmabuf_export_remote(void *data)
sgt_info = kmalloc(sizeof(*sgt_info), GFP_KERNEL);
- sgt_info->hyper_dmabuf_id = hyper_dmabuf_id_gen(); + sgt_info->hyper_dmabuf_id = hyper_dmabuf_get_id(); /* TODO: We might need to consider using port number on event channel? */ sgt_info->hyper_dmabuf_rdomain = export_remote_attr->remote_domain; sgt_info->dma_buf = dma_buf; @@ -334,6 +325,8 @@ static int hyper_dmabuf_unexport(void *data) hyper_dmabuf_cleanup_sgt_info(sgt_info, false); hyper_dmabuf_remove_exported(unexport_attr->hyper_dmabuf_id); kfree(sgt_info); + /* register hyper_dmabuf_id to the list for reuse */ + store_reusable_id(unexport_attr->hyper_dmabuf_id); }
return ret; diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_remote_sync.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_remote_sync.c index 5017b17..c5950e0 100644 --- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_remote_sync.c +++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_remote_sync.c @@ -6,6 +6,7 @@ #include "hyper_dmabuf_struct.h" #include "hyper_dmabuf_list.h" #include "hyper_dmabuf_drv.h" +#include "hyper_dmabuf_id.h" #include "xen/hyper_dmabuf_xen_comm.h" #include "hyper_dmabuf_msg.h" #include "hyper_dmabuf_imp.h" @@ -124,6 +125,8 @@ int hyper_dmabuf_remote_sync(int id, int ops) hyper_dmabuf_cleanup_sgt_info(sgt_info, false); hyper_dmabuf_remove_exported(id); kfree(sgt_info); + /* store hyper_dmabuf_id in the list for reuse */ + store_reusable_id(id); }
break; diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_struct.h b/drivers/xen/hyper_dmabuf/hyper_dmabuf_struct.h index 92e06ff..b52f958 100644 --- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_struct.h +++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_struct.h @@ -3,15 +3,6 @@
#include <xen/interface/grant_table.h>
-/* Importer combine source domain id with given hyper_dmabuf_id - * to make it unique in case there are multiple exporters */ - -#define HYPER_DMABUF_ID_IMPORTER(domid, id) \ - ((((domid) & 0xFF) << 24) | ((id) & 0xFFFFFF)) - -#define HYPER_DMABUF_DOM_ID(id) \ - (((id) >> 24) & 0xFF) - /* each grant_ref_t is 4 bytes, so total 4096 grant_ref_t can be * in this block meaning we can share 4KB*4096 = 16MB of buffer * (needs to be increased for large buffer use-cases such as 4K