io_uring: move max entry definition and ring sizing into header

In preparation for needing this somewhere else, move the definitions
for the maximum CQ and SQ ring size into io_uring.h. Make the
rings_size() helper available as well, and have it take just the setup
flags argument rather than the fill ring pointer. That's all that is
needed.

Signed-off-by: Jens Axboe <[email protected]>

Author: axboe

io_uring/io_uring.c

@@ -105,9 +105,6 @@
 #include "alloc_cache.h"
 #include "eventfd.h"
 
-#define IORING_MAX_ENTRIES	32768
-#define IORING_MAX_CQ_ENTRIES	(2 * IORING_MAX_ENTRIES)
-
 #define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \
 			  IOSQE_IO_HARDLINK | IOSQE_ASYNC)
 
@@ -2667,16 +2664,16 @@ static void io_rings_free(struct io_ring_ctx *ctx)
 	ctx->sq_sqes = NULL;
 }
 
-static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries,
-				unsigned int cq_entries, size_t *sq_offset)
+unsigned long rings_size(unsigned int flags, unsigned int sq_entries,
+			 unsigned int cq_entries, size_t *sq_offset)
 {
 	struct io_rings *rings;
 	size_t off, sq_array_size;
 
 	off = struct_size(rings, cqes, cq_entries);
 	if (off == SIZE_MAX)
 		return SIZE_MAX;
-	if (ctx->flags & IORING_SETUP_CQE32) {
+	if (flags & IORING_SETUP_CQE32) {
 		if (check_shl_overflow(off, 1, &off))
 			return SIZE_MAX;
 	}
@@ -2687,7 +2684,7 @@ static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries
 		return SIZE_MAX;
 #endif
 
-	if (ctx->flags & IORING_SETUP_NO_SQARRAY) {
+	if (flags & IORING_SETUP_NO_SQARRAY) {
 		*sq_offset = SIZE_MAX;
 		return off;
 	}
@@ -3434,7 +3431,8 @@ static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
 	ctx->sq_entries = p->sq_entries;
 	ctx->cq_entries = p->cq_entries;
 
-	size = rings_size(ctx, p->sq_entries, p->cq_entries, &sq_array_offset);
+	size = rings_size(ctx->flags, p->sq_entries, p->cq_entries,
+			  &sq_array_offset);
 	if (size == SIZE_MAX)
 		return -EOVERFLOW;
 

io_uring/io_uring.h

@@ -65,6 +65,11 @@ static inline bool io_should_wake(struct io_wait_queue *iowq)
 	return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
 }
 
+#define IORING_MAX_ENTRIES	32768
+#define IORING_MAX_CQ_ENTRIES	(2 * IORING_MAX_ENTRIES)
+
+unsigned long rings_size(unsigned int flags, unsigned int sq_entries,
+			 unsigned int cq_entries, size_t *sq_offset);
 bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow);
 int io_run_task_work_sig(struct io_ring_ctx *ctx);
 void io_req_defer_failed(struct io_kiocb *req, s32 res);