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UBI: Add initial support for scatter gather

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Adds a new set of functions to deal with scatter gather.
ubi_eba_read_leb_sg() will read from a LEB into a scatter gather list.
The new data structure struct ubi_sgl will be used within UBI to
hold the scatter gather list itself and metadata to have a cursor
within the list.

Signed-off-by: Richard Weinberger <richard@nod.at>
Tested-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
This commit is contained in:
Richard Weinberger
2015-01-10 22:52:13 +01:00
parent 892abde56c
commit 9ff08979e1
4 changed files with 186 additions and 15 deletions
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95
drivers/mtd/ubi/kapi.c
View File

@@ -365,6 +365,43 @@ void ubi_close_volume(struct ubi_volume_desc *desc)
}
EXPORT_SYMBOL_GPL(ubi_close_volume);
/**
* leb_read_sanity_check - does sanity checks on read requests.
* @desc: volume descriptor
* @lnum: logical eraseblock number to read from
* @offset: offset within the logical eraseblock to read from
* @len: how many bytes to read
*
* This function is used by ubi_leb_read() and ubi_leb_read_sg()
* to perform sanity checks.
*/
static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum,
int offset, int len)
{
struct ubi_volume *vol = desc->vol;
struct ubi_device *ubi = vol->ubi;
int vol_id = vol->vol_id;
if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
lnum >= vol->used_ebs || offset < 0 || len < 0 ||
offset + len > vol->usable_leb_size)
return -EINVAL;
if (vol->vol_type == UBI_STATIC_VOLUME) {
if (vol->used_ebs == 0)
/* Empty static UBI volume */
return 0;
if (lnum == vol->used_ebs - 1 &&
offset + len > vol->last_eb_bytes)
return -EINVAL;
}
if (vol->upd_marker)
return -EBADF;
return 0;
}
/**
* ubi_leb_read - read data.
* @desc: volume descriptor
@@ -401,22 +438,10 @@ int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
lnum >= vol->used_ebs || offset < 0 || len < 0 ||
offset + len > vol->usable_leb_size)
return -EINVAL;
err = leb_read_sanity_check(desc, lnum, offset, len);
if (err < 0)
return err;
if (vol->vol_type == UBI_STATIC_VOLUME) {
if (vol->used_ebs == 0)
/* Empty static UBI volume */
return 0;
if (lnum == vol->used_ebs - 1 &&
offset + len > vol->last_eb_bytes)
return -EINVAL;
}
if (vol->upd_marker)
return -EBADF;
if (len == 0)
return 0;
@@ -430,6 +455,46 @@ int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
}
EXPORT_SYMBOL_GPL(ubi_leb_read);
/**
* ubi_leb_read_sg - read data into a scatter gather list.
* @desc: volume descriptor
* @lnum: logical eraseblock number to read from
* @buf: buffer where to store the read data
* @offset: offset within the logical eraseblock to read from
* @len: how many bytes to read
* @check: whether UBI has to check the read data's CRC or not.
*
* This function works exactly like ubi_leb_read_sg(). But instead of
* storing the read data into a buffer it writes to an UBI scatter gather
* list.
*/
int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
int offset, int len, int check)
{
struct ubi_volume *vol = desc->vol;
struct ubi_device *ubi = vol->ubi;
int err, vol_id = vol->vol_id;
dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
err = leb_read_sanity_check(desc, lnum, offset, len);
if (err < 0)
return err;
if (len == 0)
return 0;
err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check);
if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
vol->corrupted = 1;
}
return err;
}
EXPORT_SYMBOL_GPL(ubi_leb_read_sg);
/**
* ubi_leb_write - write data.
* @desc: volume descriptor