[PATCH 2/3] misc: fastrpc: fix map cleanup paths

[Yousef Alhouseen <alhouseenyousef@gmail.com>]

fastrpc_create_maps() can attach dma-bufs for every scalar argument,
including handle arguments beyond the input and output buffer count.
fastrpc_context_free() only dropped references up to nbufs, leaving
handle maps attached after invoke cleanup.

fastrpc_map_attach() also falls through to fastrpc_map_put() after
manually detaching and putting the dma-buf on late errors. Leave the map
object in a state that matches the resources still owned by the release
path so the attachment and dma-buf are not released twice.

Signed-off-by: Yousef Alhouseen <alhouseenyousef@gmail.com>
---
 drivers/misc/fastrpc.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 8992b5c0c..50f90e17e 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -580,7 +580,7 @@ static void fastrpc_context_free(struct kref *ref)
 	cctx = ctx->cctx;
 	fl = ctx->fl;
 
-	for (i = 0; i < ctx->nbufs; i++)
+	for (i = 0; i < ctx->nscalars; i++)
 		fastrpc_map_put(ctx->maps[i]);
 
 	if (ctx->buf)
@@ -917,7 +917,7 @@ static int fastrpc_map_attach(struct fastrpc_user *fl, int fd,
 	table = dma_buf_map_attachment_unlocked(map->attach, DMA_BIDIRECTIONAL);
 	if (IS_ERR(table)) {
 		err = PTR_ERR(table);
-		goto map_err;
+		goto detach_err;
 	}
 	map->table = table;
 
@@ -966,9 +966,15 @@ static int fastrpc_map_attach(struct fastrpc_user *fl, int fd,
 	return 0;
 
 map_err:
+	dma_buf_unmap_attachment_unlocked(map->attach, map->table,
+					  DMA_BIDIRECTIONAL);
+	map->table = NULL;
+detach_err:
 	dma_buf_detach(map->buf, map->attach);
+	map->attach = NULL;
 attach_err:
 	dma_buf_put(map->buf);
+	map->buf = NULL;
 get_err:
 	fastrpc_map_put(map);
 
-- 
2.54.0