mmc: core: convert slot functions to managed allocation

This prepares for the addition of further slot functions.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index b8c5290..74cf29a 100644 (file)
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -32,6 +32,7 @@
 static void mmc_host_classdev_release(struct device *dev)
 {
        struct mmc_host *host = cls_dev_to_mmc_host(dev);
+       mutex_destroy(&host->slot.lock);
        kfree(host);
 }
 
@@ -327,6 +328,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 
        mmc_host_clk_init(host);
 
+       mutex_init(&host->slot.lock);
        host->slot.cd_irq = -EINVAL;
 
        spin_lock_init(&host->lock);

diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c
index 92cba02..41689da 100644 (file)
--- a/drivers/mmc/core/slot-gpio.c
+++ b/drivers/mmc/core/slot-gpio.c
@@ -29,6 +29,34 @@ static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
        return IRQ_HANDLED;
 }
 
+static int mmc_gpio_alloc(struct mmc_host *host)
+{
+       size_t len = strlen(dev_name(host->parent)) + 4;
+       struct mmc_gpio *ctx;
+
+       mutex_lock(&host->slot.lock);
+
+       ctx = host->slot.handler_priv;
+       if (!ctx) {
+               /*
+                * devm_kzalloc() can be called after device_initialize(), even
+                * before device_add(), i.e., between mmc_alloc_host() and
+                * mmc_add_host()
+                */
+               ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + len,
+                                  GFP_KERNEL);
+               if (ctx) {
+                       snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
+                       ctx->cd_gpio = -EINVAL;
+                       host->slot.handler_priv = ctx;
+               }
+       }
+
+       mutex_unlock(&host->slot.lock);
+
+       return ctx ? 0 : -ENOMEM;
+}
+
 int mmc_gpio_get_cd(struct mmc_host *host)
 {
        struct mmc_gpio *ctx = host->slot.handler_priv;
@@ -43,20 +71,24 @@ EXPORT_SYMBOL(mmc_gpio_get_cd);
 
 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
 {
-       size_t len = strlen(dev_name(host->parent)) + 4;
        struct mmc_gpio *ctx;
        int irq = gpio_to_irq(gpio);
        int ret;
 
-       ctx = kmalloc(sizeof(*ctx) + len, GFP_KERNEL);
-       if (!ctx)
-               return -ENOMEM;
+       ret = mmc_gpio_alloc(host);
+       if (ret < 0)
+               return ret;
 
-       snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
+       ctx = host->slot.handler_priv;
 
        ret = gpio_request_one(gpio, GPIOF_DIR_IN, ctx->cd_label);
        if (ret < 0)
-               goto egpioreq;
+               /*
+                * don't bother freeing memory. It might still get used by other
+                * slot functions, in any case it will be freed, when the device
+                * is destroyed.
+                */
+               return ret;
 
        /*
         * Even if gpio_to_irq() returns a valid IRQ number, the platform might
@@ -80,13 +112,8 @@ int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
                host->caps |= MMC_CAP_NEEDS_POLL;
 
        ctx->cd_gpio = gpio;
-       host->slot.handler_priv = ctx;
 
        return 0;
-
-egpioreq:
-       kfree(ctx);
-       return ret;
 }
 EXPORT_SYMBOL(mmc_gpio_request_cd);
 
@@ -107,7 +134,5 @@ void mmc_gpio_free_cd(struct mmc_host *host)
        ctx->cd_gpio = -EINVAL;
 
        gpio_free(gpio);
-       host->slot.handler_priv = NULL;
-       kfree(ctx);
 }
 EXPORT_SYMBOL(mmc_gpio_free_cd);

diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index c1a03ee..65c64ee 100644 (file)
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -11,6 +11,7 @@
 #define LINUX_MMC_HOST_H
 
 #include <linux/leds.h>
+#include <linux/mutex.h>
 #include <linux/sched.h>
 #include <linux/device.h>
 #include <linux/fault-inject.h>
@@ -154,6 +155,7 @@ struct mmc_async_req {
  * struct mmc_slot - MMC slot functions
  *
  * @cd_irq:            MMC/SD-card slot hotplug detection IRQ or -EINVAL
+ * @lock:              protect the @handler_priv pointer
  * @handler_priv:      MMC/SD-card slot context
  *
  * Some MMC/SD host controllers implement slot-functions like card and
@@ -163,6 +165,7 @@ struct mmc_async_req {
  */
 struct mmc_slot {
        int cd_irq;
+       struct mutex lock;
        void *handler_priv;
 };