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authorPer Forlin <per.forlin@linaro.org>2011-08-29 15:35:58 +0200
committerChris Ball <cjb@laptop.org>2011-10-26 16:32:04 -0400
commit7c8a2829c22a270acadc6aa3a937e2e7956b19f5 (patch)
treeb787b429a1bd01f364e752fe5b52e2f95cb46875 /include
parent44669034815a7ad263542ac605c581a10b22d146 (diff)
downloadlinux-7c8a2829c22a270acadc6aa3a937e2e7956b19f5.tar.gz
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>
Diffstat (limited to 'include')
-rw-r--r--include/linux/mmc/host.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 4c4bddf5ef61..340cc0c9409f 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -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);