mmc: core: move ->request() call from atomic context

mmc_request_done() is sometimes called from interrupt or other atomic
context.  Mostly all mmc_request_done() does is complete(), however it
contains code to retry on error, which uses ->request().  As the error
path is certainly not performance critical, this may be moved to the
waiting function mmc_wait_for_req_done().

This allows ->request() to use runtime PM get_sync() and guarantee it
is never in an atomic context.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Ulf Hansson <ulf.hansson@stericsson.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/core/core.c

@@ -141,12 +141,12 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
 	}
 
 	if (err && cmd->retries) {
-		pr_debug("%s: req failed (CMD%u): %d, retrying...\n",
-			mmc_hostname(host), cmd->opcode, err);
-
-		cmd->retries--;
-		cmd->error = 0;
-		host->ops->request(host, mrq);
+		/*
+		 * Request starter must handle retries - see
+		 * mmc_wait_for_req_done().
+		 */
+		if (mrq->done)
+			mrq->done(mrq);
 	} else {
 		mmc_should_fail_request(host, mrq);
 
@@ -253,7 +253,21 @@ static void __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq)
 static void mmc_wait_for_req_done(struct mmc_host *host,
 				  struct mmc_request *mrq)
 {
-	wait_for_completion(&mrq->completion);
+	struct mmc_command *cmd;
+
+	while (1) {
+		wait_for_completion(&mrq->completion);
+
+		cmd = mrq->cmd;
+		if (!cmd->error || !cmd->retries)
+			break;
+
+		pr_debug("%s: req failed (CMD%u): %d, retrying...\n",
+			 mmc_hostname(host), cmd->opcode, cmd->error);
+		cmd->retries--;
+		cmd->error = 0;
+		host->ops->request(host, mrq);
+	}
 }
 
 /**