[SCSI] tgt: fix the user/kernel ring buffer interface
This patches fixes two bugs in the scsi target infrastructure's
user/kernel interface.
- It wrongly assumes that the ring buffer size of the interface (64KB)
is larger than or equal to the system page size. This patch sets the
ring buffer size to PAGE_SIZE if the system page size is larger.
- It uses PAGE_SIZE in the header file exported to userspace. This
patch removes it.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/scsi_tgt_if.c b/drivers/scsi/scsi_tgt_if.c
index f2344ab..0e08817 100644
--- a/drivers/scsi/scsi_tgt_if.c
+++ b/drivers/scsi/scsi_tgt_if.c
@@ -33,6 +33,14 @@
#include "scsi_tgt_priv.h"
+#if TGT_RING_SIZE < PAGE_SIZE
+# define TGT_RING_SIZE PAGE_SIZE
+#endif
+
+#define TGT_RING_PAGES (TGT_RING_SIZE >> PAGE_SHIFT)
+#define TGT_EVENT_PER_PAGE (PAGE_SIZE / sizeof(struct tgt_event))
+#define TGT_MAX_EVENTS (TGT_EVENT_PER_PAGE * TGT_RING_PAGES)
+
struct tgt_ring {
u32 tr_idx;
unsigned long tr_pages[TGT_RING_PAGES];
