Commit 7c8a2829 authored Aug 29, 2011 by Per Forlin Committed by Chris Ball Oct 26, 2011

mmc: core: clarify how to use post_req in case of errors



The err condition in post_req() is set to undo a call made to pre_req()
that hasn't been started yet.  The err condition is not set if an MMC
request returns an error.

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

parent 44669034

drivers/mmc/core/core.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -320,8 +320,14 @@ struct mmc_async_req mmc_start_req(struct mmc_host host,
		mmc_wait_for_req_done(host, host->areq->mrq);
		err = host->areq->err_check(host->card, host->areq);
		if (err) {
		/* post process the completed failed request */
		mmc_post_req(host, host->areq->mrq, 0);
		if (areq)
		/*
		* Cancel the new prepared request, because
		* it can't run until the failed
		* request has been properly handled.
		*/
		mmc_post_req(host, areq->mrq, -EINVAL);

		host->areq = NULL;

include/linux/mmc/host.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -109,6 +109,9 @@ struct mmc_host_ops {
		* It is optional for the host to implement pre_req and post_req in
		* order to support double buffering of requests (prepare one
		* request while another request is active).
		* pre_req() must always be followed by a post_req().
		* To undo a call made to pre_req(), call post_req() with
		* a nonzero err condition.
		*/
		void (post_req)(struct mmc_host host, struct mmc_request *req,
		int err);