mmc: core: Do not pre-claim host in suspend
authorUlf Hansson <ulf.hansson@stericsson.com>
Thu, 19 Apr 2012 09:55:25 +0000 (11:55 +0200)
committerChris Ball <cjb@laptop.org>
Sat, 21 Apr 2012 01:52:13 +0000 (21:52 -0400)
Since SDIO drivers may want to do some SDIO operations in their suspend
callback functions, we must not keep the host claimed when calling them.

Daniel Drake reported that libertas_sdio encountered a deadlock in its
suspend function.

Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Tested-by: Daniel Drake <dsd@laptop.org>
[stable@: please apply to 3.2-stable and 3.3-stable]
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
drivers/mmc/core/core.c

index e541efbf32560494678700b54cf7ac9fba090d3d..ba821fe70bca03dd3fbf17661e150ff737af242c 100644 (file)
@@ -2238,6 +2238,7 @@ int mmc_cache_ctrl(struct mmc_host *host, u8 enable)
                        mmc_card_is_removable(host))
                return err;
 
+       mmc_claim_host(host);
        if (card && mmc_card_mmc(card) &&
                        (card->ext_csd.cache_size > 0)) {
                enable = !!enable;
@@ -2255,6 +2256,7 @@ int mmc_cache_ctrl(struct mmc_host *host, u8 enable)
                                card->ext_csd.cache_ctrl = enable;
                }
        }
+       mmc_release_host(host);
 
        return err;
 }
@@ -2272,49 +2274,32 @@ int mmc_suspend_host(struct mmc_host *host)
 
        cancel_delayed_work(&host->detect);
        mmc_flush_scheduled_work();
-       if (mmc_try_claim_host(host)) {
-               err = mmc_cache_ctrl(host, 0);
-               mmc_release_host(host);
-       } else {
-               err = -EBUSY;
-       }
 
+       err = mmc_cache_ctrl(host, 0);
        if (err)
                goto out;
 
        mmc_bus_get(host);
        if (host->bus_ops && !host->bus_dead) {
 
-               /*
-                * A long response time is not acceptable for device drivers
-                * when doing suspend. Prevent mmc_claim_host in the suspend
-                * sequence, to potentially wait "forever" by trying to
-                * pre-claim the host.
-                */
-               if (mmc_try_claim_host(host)) {
-                       if (host->bus_ops->suspend) {
-                               err = host->bus_ops->suspend(host);
-                       }
-                       mmc_release_host(host);
+               if (host->bus_ops->suspend)
+                       err = host->bus_ops->suspend(host);
 
-                       if (err == -ENOSYS || !host->bus_ops->resume) {
-                               /*
-                                * We simply "remove" the card in this case.
-                                * It will be redetected on resume.  (Calling
-                                * bus_ops->remove() with a claimed host can
-                                * deadlock.)
-                                */
-                               if (host->bus_ops->remove)
-                                       host->bus_ops->remove(host);
-                               mmc_claim_host(host);
-                               mmc_detach_bus(host);
-                               mmc_power_off(host);
-                               mmc_release_host(host);
-                               host->pm_flags = 0;
-                               err = 0;
-                       }
-               } else {
-                       err = -EBUSY;
+               if (err == -ENOSYS || !host->bus_ops->resume) {
+                       /*
+                        * We simply "remove" the card in this case.
+                        * It will be redetected on resume.  (Calling
+                        * bus_ops->remove() with a claimed host can
+                        * deadlock.)
+                        */
+                       if (host->bus_ops->remove)
+                               host->bus_ops->remove(host);
+                       mmc_claim_host(host);
+                       mmc_detach_bus(host);
+                       mmc_power_off(host);
+                       mmc_release_host(host);
+                       host->pm_flags = 0;
+                       err = 0;
                }
        }
        mmc_bus_put(host);