MMC: Block: Ensure hardware partitions don't mess with mmcblk device naming.

Commit Message

Andrei Warkentin April 22, 2011, 3:46 a.m. UTC

With the hardware partitions support (which represent additional logical devices
present on MMC), devidx does not correspond with index used to form
/dev/mmcblkX names. So use an additional allocated index for device names.

Signed-off-by: Andrei Warkentin <[e-mail]>
---
 drivers/mmc/card/block.c |   26 +++++++++++++++++++-------
 1 files changed, 19 insertions(+), 7 deletions(-)

Comments

Andrei Warkentin April 22, 2011, 3:50 a.m. UTC | #1

On Thu, Apr 21, 2011 at 10:46 PM, Andrei Warkentin <[e-mail]> wrote:
> With the hardware partitions support (which represent additional logical devices
> present on MMC), devidx does not correspond with index used to form
> /dev/mmcblkX names. So use an additional allocated index for device names.
>
> Signed-off-by: Andrei Warkentin <[e-mail]>

That should be good :-/. Sorry.

A
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Chris Ball April 22, 2011, 10:34 p.m. UTC | #2

Hi Andrei,

On Thu, Apr 21 2011, Andrei Warkentin wrote:
> With the hardware partitions support (which represent additional logical devices
> present on MMC), devidx does not correspond with index used to form
> /dev/mmcblkX names. So use an additional allocated index for device names.
>
> Signed-off-by: Andrei Warkentin <[e-mail]>

Thanks, pushed to mmc-next for .40, looks good:

[  659.127819] mmc0: new high speed SDHC card at address d555
[  659.141704] mmcblk1: mmc0:d555 SD04G 3.79 GiB 
[  659.147453]  mmcblk1: p1

(I re-wrapped the commit message and comment to <80 chars.)

- Chris.

Patch

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 9e30cf6..92e4a00 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -75,6 +75,7 @@  static int max_devices;
 
 /* 256 minors, so at most 256 separate devices */
 static DECLARE_BITMAP(dev_use, 256);
+static DECLARE_BITMAP(name_use, 256);
 
 /*
  * There is one mmc_blk_data per slot.
@@ -88,6 +89,7 @@  struct mmc_blk_data {
 	unsigned int	usage;
 	unsigned int	read_only;
 	unsigned int	part_type;
+	unsigned int	name_idx;
 
 	/*
 	 * Only set in main mmc_blk_data associated
@@ -776,6 +778,20 @@  static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 	}
 
 	/*
+	 * !subname implies we are creating main mmc_blk_data that will be
+	 * associated with mmc_card with mmc_set_drvdata. Due to device partitions,
+	 * devidx will not coincide with a per-physical card index anymore
+	 * so we keep track of a name index.
+	 */
+	if (!subname) {
+		md->name_idx = find_first_zero_bit(name_use, max_devices);
+		__set_bit(md->name_idx, name_use);
+	}
+	else
+		md->name_idx = ((struct mmc_blk_data *)
+				dev_to_disk(parent)->private_data)->name_idx;
+
+	/*
 	 * Set the read-only status based on the supported commands
 	 * and the write protect switch.
 	 */
@@ -820,13 +836,8 @@  static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 	 * messages to tell when the card is present.
 	 */
 
-	if (subname)
-		snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
-			 "mmcblk%d%s",
-			 mmc_get_devidx(dev_to_disk(parent)), subname);
-	else
-		snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
-			 "mmcblk%d", devidx);
+	snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
+		 "mmcblk%d%s", md->name_idx, subname ? subname : "");
 
 	blk_queue_logical_block_size(md->queue.queue, 512);
 	set_capacity(md->disk, size);
@@ -953,6 +964,7 @@  static void mmc_blk_remove_parts(struct mmc_card *card,
 	struct list_head *pos, *q;
 	struct mmc_blk_data *part_md;
 
+	__clear_bit(md->name_idx, name_use);
 	list_for_each_safe(pos, q, &md->part) {
 		part_md = list_entry(pos, struct mmc_blk_data, part);
 		list_del(pos);