mmc: make number of mmcblk minors configurable

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / mmc / card / block.c

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index a9970504cabbad33f7830bfeebcf1120bb2138a1..217f82037fc1c398f12b90dc9859d7a6344ac366 100644 (file)
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -43,15 +43,27 @@
 #include "queue.h"
 
 MODULE_ALIAS("mmc:block");
+#ifdef MODULE_PARAM_PREFIX
+#undef MODULE_PARAM_PREFIX
+#endif
+#define MODULE_PARAM_PREFIX "mmcblk."
+
+static DEFINE_MUTEX(block_mutex);
 
 /*
- * max 8 partitions per card
+ * The defaults come from config options but can be overriden by module
+ * or bootarg options.
  */
-#define MMC_SHIFT      3
-#define MMC_NUM_MINORS (256 >> MMC_SHIFT)
+static int perdev_minors = CONFIG_MMC_BLOCK_MINORS;
 
-static DEFINE_MUTEX(block_mutex);
-static DECLARE_BITMAP(dev_use, MMC_NUM_MINORS);
+/*
+ * We've only got one major, so number of mmcblk devices is
+ * limited to 256 / number of minors per device.
+ */
+static int max_devices;
+
+/* 256 minors, so at most 256 separate devices */
+static DECLARE_BITMAP(dev_use, 256);
 
 /*
  * There is one mmc_blk_data per slot.
@@ -67,6 +79,9 @@ struct mmc_blk_data {
 
 static DEFINE_MUTEX(open_lock);
 
+module_param(perdev_minors, int, 0444);
+MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device");
+
 static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
 {
        struct mmc_blk_data *md;
@@ -88,10 +103,10 @@ static void mmc_blk_put(struct mmc_blk_data *md)
        md->usage--;
        if (md->usage == 0) {
                int devmaj = MAJOR(disk_devt(md->disk));
-               int devidx = MINOR(disk_devt(md->disk)) >> MMC_SHIFT;
+               int devidx = MINOR(disk_devt(md->disk)) / perdev_minors;
 
                if (!devmaj)
-                       devidx = md->disk->first_minor >> MMC_SHIFT;
+                       devidx = md->disk->first_minor / perdev_minors;
 
                blk_cleanup_queue(md->queue.queue);
 
@@ -566,8 +581,8 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
        struct mmc_blk_data *md;
        int devidx, ret;
 
-       devidx = find_first_zero_bit(dev_use, MMC_NUM_MINORS);
-       if (devidx >= MMC_NUM_MINORS)
+       devidx = find_first_zero_bit(dev_use, max_devices);
+       if (devidx >= max_devices)
                return ERR_PTR(-ENOSPC);
        __set_bit(devidx, dev_use);
 
@@ -584,7 +599,7 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
         */
        md->read_only = mmc_blk_readonly(card);
 
-       md->disk = alloc_disk(1 << MMC_SHIFT);
+       md->disk = alloc_disk(perdev_minors);
        if (md->disk == NULL) {
                ret = -ENOMEM;
                goto err_kfree;
@@ -601,7 +616,7 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
        md->queue.data = md;
 
        md->disk->major = MMC_BLOCK_MAJOR;
-       md->disk->first_minor = devidx << MMC_SHIFT;
+       md->disk->first_minor = devidx * perdev_minors;
        md->disk->fops = &mmc_bdops;
        md->disk->private_data = md;
        md->disk->queue = md->queue.queue;
@@ -670,7 +685,6 @@ static int mmc_blk_probe(struct mmc_card *card)
 {
        struct mmc_blk_data *md;
        int err;
-
        char cap_str[10];
 
        /*
@@ -760,6 +774,11 @@ static int __init mmc_blk_init(void)
 {
        int res;
 
+       if (perdev_minors != CONFIG_MMC_BLOCK_MINORS)
+               pr_info("mmcblk: using %d minors per device\n", perdev_minors);
+
+       max_devices = 256 / perdev_minors;
+
        res = register_blkdev(MMC_BLOCK_MAJOR, "mmc");
        if (res)
                goto out;