[PATCH] mtd: sm_ftl: allocate cis_buffer with main struct

[PATCH] mtd: sm_ftl: allocate cis_buffer with main struct

[Rosen Penev]

Use a flexible array member and kzalloc_flex() to do so. Simplifies
memory allocation slightly.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/mtd/sm_ftl.c | 30 +++++++++++-------------------
 drivers/mtd/sm_ftl.h |  2 +-
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/drivers/mtd/sm_ftl.c b/drivers/mtd/sm_ftl.c
index c8032755f9a4..fb0f97fb94f0 100644
--- a/drivers/mtd/sm_ftl.c
+++ b/drivers/mtd/sm_ftl.c
@@ -1133,7 +1133,7 @@ static void sm_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
 	struct sm_ftl *ftl;
 
 	/* Allocate & initialize our private structure */
-	ftl = kzalloc_obj(struct sm_ftl);
+	ftl = kzalloc_flex(*ftl, cis_buffer, SM_SECTOR_SIZE);
 	if (!ftl)
 		goto error1;
 
@@ -1145,25 +1145,20 @@ static void sm_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
 	/* Read media information */
 	if (sm_get_media_info(ftl, mtd)) {
 		dbg("found unsupported mtd device, aborting");
-		goto error2;
+		goto error1;
 	}
 
 
-	/* Allocate temporary CIS buffer for read retry support */
-	ftl->cis_buffer = kzalloc(SM_SECTOR_SIZE, GFP_KERNEL);
-	if (!ftl->cis_buffer)
-		goto error2;
-
 	/* Allocate zone array, it will be initialized on demand */
 	ftl->zones = kzalloc_objs(struct ftl_zone, ftl->zone_count);
 	if (!ftl->zones)
-		goto error3;
+		goto error2;
 
 	/* Allocate the cache*/
 	ftl->cache_data = kzalloc(ftl->block_size, GFP_KERNEL);
 
 	if (!ftl->cache_data)
-		goto error4;
+		goto error3;
 
 	sm_cache_init(ftl);
 
@@ -1171,7 +1166,7 @@ static void sm_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
 	/* Allocate upper layer structure and initialize it */
 	trans = kzalloc_obj(struct mtd_blktrans_dev);
 	if (!trans)
-		goto error5;
+		goto error4;
 
 	ftl->trans = trans;
 	trans->priv = ftl;
@@ -1184,12 +1179,12 @@ static void sm_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
 
 	if (sm_find_cis(ftl)) {
 		dbg("CIS not found on mtd device, aborting");
-		goto error6;
+		goto error5;
 	}
 
 	ftl->disk_attributes = sm_create_sysfs_attributes(ftl);
 	if (!ftl->disk_attributes)
-		goto error6;
+		goto error5;
 	trans->disk_attributes = ftl->disk_attributes;
 
 	sm_printk("Found %d MiB xD/SmartMedia FTL on mtd%d",
@@ -1206,17 +1201,15 @@ static void sm_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
 	/* Register device*/
 	if (add_mtd_blktrans_dev(trans)) {
 		dbg("error in mtdblktrans layer");
-		goto error6;
+		goto error5;
 	}
 	return;
-error6:
-	kfree(trans);
 error5:
-	kfree(ftl->cache_data);
+	kfree(trans);
 error4:
-	kfree(ftl->zones);
+	kfree(ftl->cache_data);
 error3:
-	kfree(ftl->cis_buffer);
+	kfree(ftl->zones);
 error2:
 	kfree(ftl);
 error1:
@@ -1242,7 +1235,6 @@ static void sm_remove_dev(struct mtd_blktrans_dev *dev)
 	}
 
 	sm_delete_sysfs_attributes(ftl);
-	kfree(ftl->cis_buffer);
 	kfree(ftl->zones);
 	kfree(ftl->cache_data);
 	kfree(ftl);
diff --git a/drivers/mtd/sm_ftl.h b/drivers/mtd/sm_ftl.h
index 6aed8b60de16..1a1a54ce836a 100644
--- a/drivers/mtd/sm_ftl.h
+++ b/drivers/mtd/sm_ftl.h
@@ -39,7 +39,6 @@ struct sm_ftl {
 	int cis_block;			/* CIS block location */
 	int cis_boffset;		/* CIS offset in the block */
 	int cis_page_offset;		/* CIS offset in the page */
-	void *cis_buffer;		/* tmp buffer for cis reads */
 
 	/* Cache */
 	int cache_block;		/* block number of cached block */
@@ -56,6 +55,7 @@ struct sm_ftl {
 	int cylinders;
 
 	struct attribute_group *disk_attributes;
+	u8 cis_buffer[];		/* tmp buffer for cis reads */
 };
 
 struct chs_entry {
-- 
2.54.0

Re: [PATCH] mtd: sm_ftl: allocate cis_buffer with main struct

[Miquel Raynal]

On Thu, 30 Apr 2026 15:07:19 -0700, Rosen Penev wrote:
> Use a flexible array member and kzalloc_flex() to do so. Simplifies
> memory allocation slightly.
> 
> 

Applied to mtd/next, thanks!

[1/1] mtd: sm_ftl: allocate cis_buffer with main struct
      commit: 87eee18f2974c0b1d854b6228408b93c6bc91744

Patche(s) should be available on mtd/linux.git and will be
part of the next PR (provided that no robot complains by then).

Kind regards,
Miquèl

Re: [PATCH] mtd: sm_ftl: allocate cis_buffer with main struct

[Miquel Raynal]

Hi Rosen,

On 30/04/2026 at 15:07:19 -07, Rosen Penev <rosenp@gmail.com> wrote:

> Use a flexible array member and kzalloc_flex() to do so. Simplifies
> memory allocation slightly.
>
> Signed-off-by: Rosen Penev <rosenp@gmail.com>

Applied to mtd/next.

Thanks,
Miquèl