UBI: introduce the VID buffer concept

Currently, all VID headers are allocated and freed using the
ubi_zalloc_vid_hdr() and ubi_free_vid_hdr() function. These functions
make sure to align allocation on ubi->vid_hdr_alsize and adjust the
vid_hdr pointer to match the ubi->vid_hdr_shift requirements.
This works fine, but is a bit convoluted.
Moreover, the future introduction of LEB consolidation (needed to support
MLC/TLC NANDs) will allows a VID buffer to contain more than one VID
header.

Hence the creation of a ubi_vid_io_buf struct to attach extra information
to the VID header.

We currently only store the actual pointer of the underlying buffer, but
will soon add the number of VID headers contained in the buffer.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

1 files changed, 22 insertions, 17 deletions

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index ff8cafe1e5cd..b6fb8f945c21 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -502,6 +502,7 @@ static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 	loff_t addr;
 	uint32_t data = 0;
 	struct ubi_ec_hdr ec_hdr;
+	struct ubi_vid_io_buf vidb;
 
 	/*
 	 * Note, we cannot generally define VID header buffers on stack,
@@ -528,7 +529,10 @@ static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 			goto error;
 	}
 
-	err = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
+	ubi_init_vid_buf(ubi, &vidb, &vid_hdr);
+	ubi_assert(&vid_hdr == ubi_get_vid_hdr(&vidb));
+
+	err = ubi_io_read_vid_hdr(ubi, pnum, &vidb, 0);
 	if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
 	    err != UBI_IO_FF){
 		addr += ubi->vid_hdr_aloffset;
@@ -995,12 +999,11 @@ bad:
  * ubi_io_read_vid_hdr - read and check a volume identifier header.
  * @ubi: UBI device description object
  * @pnum: physical eraseblock number to read from
- * @vid_hdr: &struct ubi_vid_hdr object where to store the read volume
- * identifier header
+ * @vidb: the volume identifier buffer to store data in
  * @verbose: be verbose if the header is corrupted or wasn't found
  *
  * This function reads the volume identifier header from physical eraseblock
- * @pnum and stores it in @vid_hdr. It also checks CRC checksum of the read
+ * @pnum and stores it in @vidb. It also checks CRC checksum of the read
  * volume identifier header. The error codes are the same as in
  * 'ubi_io_read_ec_hdr()'.
  *
@@ -1008,16 +1011,16 @@ bad:
  * 'ubi_io_read_ec_hdr()', so refer commentaries in 'ubi_io_read_ec_hdr()'.
  */
 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
-			struct ubi_vid_hdr *vid_hdr, int verbose)
+			struct ubi_vid_io_buf *vidb, int verbose)
 {
 	int err, read_err;
 	uint32_t crc, magic, hdr_crc;
-	void *p;
+	struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
+	void *p = vidb->buffer;
 
 	dbg_io("read VID header from PEB %d", pnum);
 	ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 
-	p = (char *)vid_hdr - ubi->vid_hdr_shift;
 	read_err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
 			  ubi->vid_hdr_shift + UBI_VID_HDR_SIZE);
 	if (read_err && read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
@@ -1080,23 +1083,24 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
  * ubi_io_write_vid_hdr - write a volume identifier header.
  * @ubi: UBI device description object
  * @pnum: the physical eraseblock number to write to
- * @vid_hdr: the volume identifier header to write
+ * @vidb: the volume identifier buffer to write
  *
  * This function writes the volume identifier header described by @vid_hdr to
  * physical eraseblock @pnum. This function automatically fills the
- * @vid_hdr->magic and the @vid_hdr->version fields, as well as calculates
- * header CRC checksum and stores it at vid_hdr->hdr_crc.
+ * @vidb->hdr->magic and the @vidb->hdr->version fields, as well as calculates
+ * header CRC checksum and stores it at vidb->hdr->hdr_crc.
  *
  * This function returns zero in case of success and a negative error code in
  * case of failure. If %-EIO is returned, the physical eraseblock probably went
  * bad.
  */
 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
-			 struct ubi_vid_hdr *vid_hdr)
+			 struct ubi_vid_io_buf *vidb)
 {
+	struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
 	int err;
 	uint32_t crc;
-	void *p;
+	void *p = vidb->buffer;
 
 	dbg_io("write VID header to PEB %d", pnum);
 	ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
@@ -1117,7 +1121,6 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
 	if (ubi_dbg_power_cut(ubi, POWER_CUT_VID_WRITE))
 		return -EROFS;
 
-	p = (char *)vid_hdr - ubi->vid_hdr_shift;
 	err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
 			   ubi->vid_hdr_alsize);
 	return err;
@@ -1283,17 +1286,19 @@ static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
 {
 	int err;
 	uint32_t crc, hdr_crc;
+	struct ubi_vid_io_buf *vidb;
 	struct ubi_vid_hdr *vid_hdr;
 	void *p;
 
 	if (!ubi_dbg_chk_io(ubi))
 		return 0;
 
-	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
-	if (!vid_hdr)
+	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
+	if (!vidb)
 		return -ENOMEM;
 
-	p = (char *)vid_hdr - ubi->vid_hdr_shift;
+	vid_hdr = ubi_get_vid_hdr(vidb);
+	p = vidb->buffer;
 	err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
 			  ubi->vid_hdr_alsize);
 	if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
@@ -1314,7 +1319,7 @@ static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
 	err = self_check_vid_hdr(ubi, pnum, vid_hdr);
 
 exit:
-	ubi_free_vid_hdr(ubi, vid_hdr);
+	ubi_free_vid_buf(vidb);
 	return err;
 }