[PATCH 11/16] io_uring: add buffer unmap helper

[Pavel Begunkov <asml.silence@gmail.com>]

Add a helper for unmapping registered buffers, better than double
indexing and will be reused in the future.

Suggested-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 143afe827cad..157e8b6f1fc4 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8098,25 +8098,27 @@ static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
 	return off;
 }
 
+static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf *imu)
+{
+	unsigned int i;
+
+	for (i = 0; i < imu->nr_bvecs; i++)
+		unpin_user_page(imu->bvec[i].bv_page);
+	if (imu->acct_pages)
+		io_unaccount_mem(ctx, imu->acct_pages);
+	kvfree(imu->bvec);
+	imu->nr_bvecs = 0;
+}
+
 static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
 {
-	int i, j;
+	unsigned int i;
 
 	if (!ctx->user_bufs)
 		return -ENXIO;
 
-	for (i = 0; i < ctx->nr_user_bufs; i++) {
-		struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
-
-		for (j = 0; j < imu->nr_bvecs; j++)
-			unpin_user_page(imu->bvec[j].bv_page);
-
-		if (imu->acct_pages)
-			io_unaccount_mem(ctx, imu->acct_pages);
-		kvfree(imu->bvec);
-		imu->nr_bvecs = 0;
-	}
-
+	for (i = 0; i < ctx->nr_user_bufs; i++)
+		io_buffer_unmap(ctx, &ctx->user_bufs[i]);
 	kfree(ctx->user_bufs);
 	ctx->user_bufs = NULL;
 	ctx->nr_user_bufs = 0;
-- 
2.24.0