Merge branch 'linux-next' of git://git.infradead.org/ubi-2.6

* 'linux-next' of git://git.infradead.org/ubi-2.6:
  UBI: tighten the corrupted PEB criteria
  UBI: fix check_data_ff return code
  UBI: remember copy_flag while scanning
  UBI: preserve corrupted PEBs
  UBI: add truly corrupted PEBs to corrupted list
  UBI: introduce debugging helper function
  UBI: make check_pattern function non-static
  UBI: do not put eraseblocks to the corrupted list unnecessarily
  UBI: separate out corrupted list
  UBI: change cascade of ifs to switch statements
  UBI: rename a local variable
  UBI: handle bit-flips when no header found
  UBI: remove duplicate IO error codes
  UBI: rename IO error code
  UBI: fix small 80 characters limit style issue
  UBI: cleanup and simplify Kconfig

1 files changed, 50 insertions, 88 deletions

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 332f992f13d9..c2960ac9f39c 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -376,25 +376,6 @@ retry:
         return 0;
 }
 
-/**
- * check_pattern - check if buffer contains only a certain byte pattern.
- * @buf: buffer to check
- * @patt: the pattern to check
- * @size: buffer size in bytes
- *
- * This function returns %1 in there are only @patt bytes in @buf, and %0 if
- * something else was also found.
- */
-static int check_pattern(const void *buf, uint8_t patt, int size)
-{
-        int i;
-
-        for (i = 0; i < size; i++)
-                if (((const uint8_t *)buf)[i] != patt)
-                        return 0;
-        return 1;
-}
-
 /* Patterns to write to a physical eraseblock when torturing it */
 static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 
@@ -426,7 +407,7 @@ static int torture_peb(struct ubi_device *ubi, int pnum)
                 if (err)
                         goto out;
 
-                err = check_pattern(ubi->peb_buf1, 0xFF, ubi->peb_size);
+                err = ubi_check_pattern(ubi->peb_buf1, 0xFF, ubi->peb_size);
                 if (err == 0) {
                         ubi_err("erased PEB %d, but a non-0xFF byte found",
                                 pnum);
@@ -445,7 +426,8 @@ static int torture_peb(struct ubi_device *ubi, int pnum)
                 if (err)
                         goto out;
 
-                err = check_pattern(ubi->peb_buf1, patterns[i], ubi->peb_size);
+                err = ubi_check_pattern(ubi->peb_buf1, patterns[i],
+                                        ubi->peb_size);
                 if (err == 0) {
                         ubi_err("pattern %x checking failed for PEB %d",
                                 patterns[i], pnum);
@@ -517,7 +499,7 @@ static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
          * In this case we probably anyway have garbage in this PEB.
          */
         err1 = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
-        if (err1 == UBI_IO_BAD_HDR_READ || err1 == UBI_IO_BAD_HDR)
+        if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR)
                 /*
                  * The VID header is corrupted, so we can safely erase this
                  * PEB and not afraid that it will be treated as a valid PEB in
@@ -712,47 +694,47 @@ bad:
  *   and corrected by the flash driver; this is harmless but may indicate that
  *   this eraseblock may become bad soon (but may be not);
  * o %UBI_IO_BAD_HDR if the erase counter header is corrupted (a CRC error);
- * o %UBI_IO_PEB_EMPTY if the physical eraseblock is empty;
+ * o %UBI_IO_BAD_HDR_EBADMSG is the same as %UBI_IO_BAD_HDR, but there also was
+ *   a data integrity error (uncorrectable ECC error in case of NAND);
+ * o %UBI_IO_FF if only 0xFF bytes were read (the PEB is supposedly empty)
  * o a negative error code in case of failure.
  */
 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
                        struct ubi_ec_hdr *ec_hdr, int verbose)
 {
-        int err, read_err = 0;
+        int err, read_err;
         uint32_t crc, magic, hdr_crc;
 
         dbg_io("read EC header from PEB %d", pnum);
         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 
-        err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
-        if (err) {
-                if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
-                        return err;
+        read_err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
+        if (read_err) {
+                if (read_err != UBI_IO_BITFLIPS && read_err != -EBADMSG)
+                        return read_err;
 
                 /*
                  * We read all the data, but either a correctable bit-flip
-                 * occurred, or MTD reported about some data integrity error,
-                 * like an ECC error in case of NAND. The former is harmless,
-                 * the later may mean that the read data is corrupted. But we
-                 * have a CRC check-sum and we will detect this. If the EC
-                 * header is still OK, we just report this as there was a
-                 * bit-flip.
+                 * occurred, or MTD reported a data integrity error
+                 * (uncorrectable ECC error in case of NAND). The former is
+                 * harmless, the later may mean that the read data is
+                 * corrupted. But we have a CRC check-sum and we will detect
+                 * this. If the EC header is still OK, we just report this as
+                 * there was a bit-flip, to force scrubbing.
                  */
-                if (err == -EBADMSG)
-                        read_err = UBI_IO_BAD_HDR_READ;
         }
 
         magic = be32_to_cpu(ec_hdr->magic);
         if (magic != UBI_EC_HDR_MAGIC) {
-                if (read_err)
-                        return read_err;
+                if (read_err == -EBADMSG)
+                        return UBI_IO_BAD_HDR_EBADMSG;
 
                 /*
                  * The magic field is wrong. Let's check if we have read all
                  * 0xFF. If yes, this physical eraseblock is assumed to be
                  * empty.
                  */
-                if (check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
+                if (ubi_check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
                         /* The physical eraseblock is supposedly empty */
                         if (verbose)
                                 ubi_warn("no EC header found at PEB %d, "
@@ -760,7 +742,10 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
                         else if (UBI_IO_DEBUG)
                                 dbg_msg("no EC header found at PEB %d, "
                                         "only 0xFF bytes", pnum);
-                        return UBI_IO_PEB_EMPTY;
+                        if (!read_err)
+                                return UBI_IO_FF;
+                        else
+                                return UBI_IO_FF_BITFLIPS;
                 }
 
                 /*
@@ -788,7 +773,11 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
                 } else if (UBI_IO_DEBUG)
                         dbg_msg("bad EC header CRC at PEB %d, calculated "
                                 "%#08x, read %#08x", pnum, crc, hdr_crc);
-                return read_err ?: UBI_IO_BAD_HDR;
+
+                if (!read_err)
+                        return UBI_IO_BAD_HDR;
+                else
+                        return UBI_IO_BAD_HDR_EBADMSG;
         }
 
         /* And of course validate what has just been read from the media */
@@ -975,22 +964,16 @@ bad:
  *
  * 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
- * volume identifier header. The following codes may be returned:
+ * volume identifier header. The error codes are the same as in
+ * 'ubi_io_read_ec_hdr()'.
  *
- * o %0 if the CRC checksum is correct and the header was successfully read;
- * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
- *   and corrected by the flash driver; this is harmless but may indicate that
- *   this eraseblock may become bad soon;
- * o %UBI_IO_BAD_HDR if the volume identifier header is corrupted (a CRC
- *   error detected);
- * o %UBI_IO_PEB_FREE if the physical eraseblock is free (i.e., there is no VID
- *   header there);
- * o a negative error code in case of failure.
+ * Note, the implementation of this function is also very similar to
+ * '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)
 {
-        int err, read_err = 0;
+        int err, read_err;
         uint32_t crc, magic, hdr_crc;
         void *p;
 
@@ -998,48 +981,29 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 
         p = (char *)vid_hdr - ubi->vid_hdr_shift;
-        err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
+        read_err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
                           ubi->vid_hdr_alsize);
-        if (err) {
-                if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
-                        return err;
-
-                /*
-                 * We read all the data, but either a correctable bit-flip
-                 * occurred, or MTD reported about some data integrity error,
-                 * like an ECC error in case of NAND. The former is harmless,
-                 * the later may mean the read data is corrupted. But we have a
-                 * CRC check-sum and we will identify this. If the VID header is
-                 * still OK, we just report this as there was a bit-flip.
-                 */
-                if (err == -EBADMSG)
-                        read_err = UBI_IO_BAD_HDR_READ;
-        }
+        if (read_err && read_err != UBI_IO_BITFLIPS && read_err != -EBADMSG)
+                return read_err;
 
         magic = be32_to_cpu(vid_hdr->magic);
         if (magic != UBI_VID_HDR_MAGIC) {
-                if (read_err)
-                        return read_err;
+                if (read_err == -EBADMSG)
+                        return UBI_IO_BAD_HDR_EBADMSG;
 
-                /*
-                 * If we have read all 0xFF bytes, the VID header probably does
-                 * not exist and the physical eraseblock is assumed to be free.
-                 */
-                if (check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
-                        /* The physical eraseblock is supposedly free */
+                if (ubi_check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
                         if (verbose)
                                 ubi_warn("no VID header found at PEB %d, "
                                          "only 0xFF bytes", pnum);
                         else if (UBI_IO_DEBUG)
                                 dbg_msg("no VID header found at PEB %d, "
                                         "only 0xFF bytes", pnum);
-                        return UBI_IO_PEB_FREE;
+                        if (!read_err)
+                                return UBI_IO_FF;
+                        else
+                                return UBI_IO_FF_BITFLIPS;
                 }
 
-                /*
-                 * This is not a valid VID header, and these are not 0xFF
-                 * bytes. Report that the header is corrupted.
-                 */
                 if (verbose) {
                         ubi_warn("bad magic number at PEB %d: %08x instead of "
                                  "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
@@ -1061,20 +1025,18 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
                 } else if (UBI_IO_DEBUG)
                         dbg_msg("bad CRC at PEB %d, calculated %#08x, "
                                 "read %#08x", pnum, crc, hdr_crc);
-                return read_err ?: UBI_IO_BAD_HDR;
+                if (!read_err)
+                        return UBI_IO_BAD_HDR;
+                else
+                        return UBI_IO_BAD_HDR_EBADMSG;
         }
 
-        /* Validate the VID header that we have just read */
         err = validate_vid_hdr(ubi, vid_hdr);
         if (err) {
                 ubi_err("validation failed for PEB %d", pnum);
                 return -EINVAL;
         }
 
-        /*
-         * If there was a read error (%-EBADMSG), but the header CRC is still
-         * OK, report about a bit-flip to force scrubbing on this PEB.
-         */
         return read_err ? UBI_IO_BITFLIPS : 0;
 }
 
@@ -1383,7 +1345,7 @@ int ubi_dbg_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
                 goto error;
         }
 
-        err = check_pattern(ubi->dbg_peb_buf, 0xFF, len);
+        err = ubi_check_pattern(ubi->dbg_peb_buf, 0xFF, len);
         if (err == 0) {
                 ubi_err("flash region at PEB %d:%d, length %d does not "
                         "contain all 0xFF bytes", pnum, offset, len);