[PATCH 1/3] mmc: core: Convert from IDR to IDA for host indexes

[PATCH 1/3] mmc: core: Convert from IDR to IDA for host indexes

[Ulf Hansson]

As IDA is more lightweight than IDR, let's convert to use that instead.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/core/host.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 6e4c55a..e0a3ee1 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -33,14 +33,14 @@
 
 #define cls_dev_to_mmc_host(d)	container_of(d, struct mmc_host, class_dev)
 
-static DEFINE_IDR(mmc_host_idr);
+static DEFINE_IDA(mmc_host_ida);
 static DEFINE_SPINLOCK(mmc_host_lock);
 
 static void mmc_host_classdev_release(struct device *dev)
 {
 	struct mmc_host *host = cls_dev_to_mmc_host(dev);
 	spin_lock(&mmc_host_lock);
-	idr_remove(&mmc_host_idr, host->index);
+	ida_remove(&mmc_host_ida, host->index);
 	spin_unlock(&mmc_host_lock);
 	kfree(host);
 }
@@ -321,14 +321,20 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 
 	/* scanning will be enabled when we're ready */
 	host->rescan_disable = 1;
-	idr_preload(GFP_KERNEL);
+
+again:
+	if (!ida_pre_get(&mmc_host_ida, GFP_KERNEL)) {
+		kfree(host);
+		return NULL;
+	}
+
 	spin_lock(&mmc_host_lock);
-	err = idr_alloc(&mmc_host_idr, host, 0, 0, GFP_NOWAIT);
-	if (err >= 0)
-		host->index = err;
+	err = ida_get_new(&mmc_host_ida, &host->index);
 	spin_unlock(&mmc_host_lock);
-	idr_preload_end();
-	if (err < 0) {
+
+	if (err == -EAGAIN) {
+		goto again;
+	} else if (err) {
 		kfree(host);
 		return NULL;
 	}
-- 
1.9.1

[PATCH 2/3] mmc: block: Release index in partition allocation error path

[Ulf Hansson]

If the allocation of a new partition fails, let's make sure to also
release the previously picked device index.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/card/block.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 8a0147d..9aaf22e 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2289,6 +2289,7 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
  err_kfree:
 	kfree(md);
  out:
+	__clear_bit(devidx, dev_use);
 	return ERR_PTR(ret);
 }
 
-- 
1.9.1

[PATCH 3/3] mmc: block: Convert to IDA for partition device indexes

[Ulf Hansson]

Instead of using an mmc specific implementation to deal with indexes
through a BITMAP, let's convert to use the IDA library.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/card/block.c | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 9aaf22e..9ce6792 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -35,6 +35,7 @@
 #include <linux/capability.h>
 #include <linux/compat.h>
 #include <linux/pm_runtime.h>
+#include <linux/idr.h>
 
 #include <linux/mmc/ioctl.h>
 #include <linux/mmc/card.h>
@@ -78,14 +79,14 @@ static int perdev_minors = CONFIG_MMC_BLOCK_MINORS;
 /*
  * We've only got one major, so number of mmcblk devices is
  * limited to (1 << 20) / number of minors per device.  It is also
- * currently limited by the size of the static bitmaps below.
+ * limited by the MAX_DEVICES below.
  */
 static int max_devices;
 
 #define MAX_DEVICES 256
 
-/* TODO: Replace these with struct ida */
-static DECLARE_BITMAP(dev_use, MAX_DEVICES);
+static DEFINE_IDA(mmc_blk_ida);
+static DEFINE_SPINLOCK(mmc_blk_lock);
 
 /*
  * There is one mmc_blk_data per slot.
@@ -178,7 +179,9 @@ static void mmc_blk_put(struct mmc_blk_data *md)
 		int devidx = mmc_get_devidx(md->disk);
 		blk_cleanup_queue(md->queue.queue);
 
-		__clear_bit(devidx, dev_use);
+		spin_lock(&mmc_blk_lock);
+		ida_remove(&mmc_blk_ida, devidx);
+		spin_unlock(&mmc_blk_lock);
 
 		put_disk(md->disk);
 		kfree(md);
@@ -2189,10 +2192,23 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 	struct mmc_blk_data *md;
 	int devidx, ret;
 
-	devidx = find_first_zero_bit(dev_use, max_devices);
-	if (devidx >= max_devices)
-		return ERR_PTR(-ENOSPC);
-	__set_bit(devidx, dev_use);
+again:
+	if (!ida_pre_get(&mmc_blk_ida, GFP_KERNEL))
+		return ERR_PTR(-ENOMEM);
+
+	spin_lock(&mmc_blk_lock);
+	ret = ida_get_new(&mmc_blk_ida, &devidx);
+	spin_unlock(&mmc_blk_lock);
+
+	if (ret == -EAGAIN)
+		goto again;
+	else if (ret)
+		return ERR_PTR(ret);
+
+	if (devidx >= max_devices) {
+		ret = -ENOSPC;
+		goto out;
+	}
 
 	md = kzalloc(sizeof(struct mmc_blk_data), GFP_KERNEL);
 	if (!md) {
@@ -2289,7 +2305,9 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
  err_kfree:
 	kfree(md);
  out:
-	__clear_bit(devidx, dev_use);
+	spin_lock(&mmc_blk_lock);
+	ida_remove(&mmc_blk_ida, devidx);
+	spin_unlock(&mmc_blk_lock);
 	return ERR_PTR(ret);
 }
 
-- 
1.9.1