[MTD] [NAND] remove len/ooblen confusion.

As was discussed between Ricard Wanderlöf, David Woodhouse, Artem 
Bityutskiy and me, the current API for reading/writing OOB is confusing. 

The thing that introduces confusion is the need to specify ops.len 
together with ops.ooblen for reads/writes that concern only OOB not data 
area. So, ops.len is overloaded: when ops.datbuf != NULL it serves to 
specify the length of the data read, and when ops.datbuf == NULL, it 
serves to specify the full OOB read length.

The patch inlined below is the slightly updated version of the previous 
patch serving the same purpose, but with the new Artem's comments taken 
into account.

Artem, BTW, thanks a lot for your valuable input!

Signed-off-by: Vitaly Wool <vwool@ru.mvista.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 9 insertions, 12 deletions

diff --git a/fs/jffs2/wbuf.c b/fs/jffs2/wbuf.c
index b9b700730dfe..dcb18e9a646e 100644
--- a/fs/jffs2/wbuf.c
+++ b/fs/jffs2/wbuf.c
@@ -968,8 +968,7 @@ int jffs2_check_oob_empty(struct jffs2_sb_info *c,
         int oobsize = c->mtd->oobsize;
         struct mtd_oob_ops ops;
 
-        ops.len = NR_OOB_SCAN_PAGES * oobsize;
-        ops.ooblen = oobsize;
+        ops.ooblen = NR_OOB_SCAN_PAGES * oobsize;
         ops.oobbuf = c->oobbuf;
         ops.ooboffs = 0;
         ops.datbuf = NULL;
@@ -982,10 +981,10 @@ int jffs2_check_oob_empty(struct jffs2_sb_info *c,
                 return ret;
         }
 
-        if (ops.retlen < ops.len) {
+        if (ops.oobretlen < ops.ooblen) {
                 D1(printk(KERN_WARNING "jffs2_check_oob_empty(): Read OOB "
                           "returned short read (%zd bytes not %d) for block "
-                          "at %08x\n", ops.retlen, ops.len, jeb->offset));
+                          "at %08x\n", ops.oobretlen, ops.ooblen, jeb->offset));
                 return -EIO;
         }
 
@@ -1004,7 +1003,7 @@ int jffs2_check_oob_empty(struct jffs2_sb_info *c,
         }
 
         /* we know, we are aligned :) */
-        for (page = oobsize; page < ops.len; page += sizeof(long)) {
+        for (page = oobsize; page < ops.ooblen; page += sizeof(long)) {
                 long dat = *(long *)(&ops.oobbuf[page]);
                 if(dat != -1)
                         return 1;
@@ -1032,7 +1031,6 @@ int jffs2_check_nand_cleanmarker (struct jffs2_sb_info *c,
                 return 2;
         }
 
-        ops.len = oobsize;
         ops.ooblen = oobsize;
         ops.oobbuf = c->oobbuf;
         ops.ooboffs = 0;
@@ -1047,10 +1045,10 @@ int jffs2_check_nand_cleanmarker (struct jffs2_sb_info *c,
                 return ret;
         }
 
-        if (ops.retlen < ops.len) {
+        if (ops.oobretlen < ops.ooblen) {
                 D1 (printk (KERN_WARNING "jffs2_check_nand_cleanmarker(): "
                             "Read OOB return short read (%zd bytes not %d) "
-                            "for block at %08x\n", ops.retlen, ops.len,
+                            "for block at %08x\n", ops.oobretlen, ops.ooblen,
                             jeb->offset));
                 return -EIO;
         }
@@ -1089,8 +1087,7 @@ int jffs2_write_nand_cleanmarker(struct jffs2_sb_info *c,
         n.nodetype = cpu_to_je16(JFFS2_NODETYPE_CLEANMARKER);
         n.totlen = cpu_to_je32(8);
 
-        ops.len = c->fsdata_len;
-        ops.ooblen = c->fsdata_len;;
+        ops.ooblen = c->fsdata_len;
         ops.oobbuf = (uint8_t *)&n;
         ops.ooboffs = c->fsdata_pos;
         ops.datbuf = NULL;
@@ -1104,10 +1101,10 @@ int jffs2_write_nand_cleanmarker(struct jffs2_sb_info *c,
                           jeb->offset, ret));
                 return ret;
         }
-        if (ops.retlen != ops.len) {
+        if (ops.oobretlen != ops.ooblen) {
                 D1(printk(KERN_WARNING "jffs2_write_nand_cleanmarker(): "
                           "Short write for block at %08x: %zd not %d\n",
-                          jeb->offset, ops.retlen, ops.len));
+                          jeb->offset, ops.oobretlen, ops.ooblen));
                 return -EIO;
         }
         return 0;