mtd: docg3 reduce read alignment burden
The read function was so far requiring the reads to be aligned on page
boundaries, and be page length multiples in size. Relieve these
constraints to ease the userspace ubifs programs runs, which read ubifs
headers of 64 bytes.
Artem: squashed a later fix from Robert Jarzmik into this patch.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index 3eafef3..2c1d0fc 100644
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -734,7 +734,7 @@
* doc_read_page_getbytes - Reads bytes from a prepared page
* @docg3: the device
* @len: the number of bytes to be read (must be a multiple of 4)
- * @buf: the buffer to be filled in
+ * @buf: the buffer to be filled in (or NULL is forget bytes)
* @first: 1 if first time read, DOC_READADDRESS should be set
*
*/
@@ -849,7 +849,7 @@
struct mtd_oob_ops *ops)
{
struct docg3 *docg3 = mtd->priv;
- int block0, block1, page, ret, ofs = 0;
+ int block0, block1, page, ret, skip, ofs = 0;
u8 *oobbuf = ops->oobbuf;
u8 *buf = ops->datbuf;
size_t len, ooblen, nbdata, nboob;
@@ -869,8 +869,7 @@
doc_dbg("doc_read_oob(from=%lld, mode=%d, data=(%p:%zu), oob=(%p:%zu))\n",
from, ops->mode, buf, len, oobbuf, ooblen);
- if ((len % DOC_LAYOUT_PAGE_SIZE) || (ooblen % DOC_LAYOUT_OOB_SIZE) ||
- (from % DOC_LAYOUT_PAGE_SIZE))
+ if (ooblen % DOC_LAYOUT_OOB_SIZE)
return -EINVAL;
ret = -EINVAL;
@@ -882,10 +881,11 @@
ops->oobretlen = 0;
ops->retlen = 0;
ret = 0;
+ skip = from % DOC_LAYOUT_PAGE_SIZE;
while (!ret && (len > 0 || ooblen > 0)) {
- calc_block_sector(from, &block0, &block1, &page, &ofs,
+ calc_block_sector(from - skip, &block0, &block1, &page, &ofs,
docg3->reliable);
- nbdata = min_t(size_t, len, (size_t)DOC_LAYOUT_PAGE_SIZE);
+ nbdata = min_t(size_t, len, DOC_LAYOUT_PAGE_SIZE - skip);
nboob = min_t(size_t, ooblen, (size_t)DOC_LAYOUT_OOB_SIZE);
ret = doc_read_page_prepare(docg3, block0, block1, page, ofs);
if (ret < 0)
@@ -893,10 +893,14 @@
ret = doc_read_page_ecc_init(docg3, DOC_ECC_BCH_TOTAL_BYTES);
if (ret < 0)
goto err_in_read;
- ret = doc_read_page_getbytes(docg3, nbdata, buf, 1);
+ ret = doc_read_page_getbytes(docg3, skip, NULL, 1);
+ if (ret < skip)
+ goto err_in_read;
+ ret = doc_read_page_getbytes(docg3, nbdata, buf, 0);
if (ret < nbdata)
goto err_in_read;
- doc_read_page_getbytes(docg3, DOC_LAYOUT_PAGE_SIZE - nbdata,
+ doc_read_page_getbytes(docg3,
+ DOC_LAYOUT_PAGE_SIZE - nbdata - skip,
NULL, 0);
ret = doc_read_page_getbytes(docg3, nboob, oobbuf, 0);
if (ret < nboob)
@@ -950,6 +954,7 @@
len -= nbdata;
ooblen -= nboob;
from += DOC_LAYOUT_PAGE_SIZE;
+ skip = 0;
}
return ret;