UBI: fix error code in ubi_io_read()

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=2362a53ec59f286495307e0e0d8ef2401e8c5c49
Commit:     2362a53ec59f286495307e0e0d8ef2401e8c5c49
Parent:     235d6200ea63372935e097cb82e6a8c133d51cad
Author:     Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
AuthorDate: Thu Oct 18 20:09:41 2007 +0300
Committer:  Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
CommitDate: Wed Dec 26 19:15:13 2007 +0200

    UBI: fix error code in ubi_io_read()
    
    When NAND detects an ECC error, it returns -EBADMSG. It does not
    stop reading requested data if one page has an ECC error, it keeps
    going and reads all the requested data. If it fails to read all
    the data, it does not return -EBADMSG, but returns the error code
    which reflects the reason of the failure.
    
    But some drivers may have bugs (e.g., OneNAND had) and stop reading
    after the first ECC error, so it returns -EBADMSG. In turn, UBI
    propagates this up to the caller. The caller will treat this as
    "all the requested data was read, but there was an ECC error".
    
    So we change the error code to -EIO if it is -EBADMSG and the read
    length is less then the requested length. We also add an assertion,
    so if UBI debugging is enabled, UBI will bug.
    
    Pointed-to-by: Adrian Hunter <ext-adrian.hunter at nokia.com>
    Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
---
 drivers/mtd/ubi/io.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 7c304ee..db3efde 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -173,6 +173,16 @@ retry:
 		ubi_err("error %d while reading %d bytes from PEB %d:%d, "
 			"read %zd bytes", err, len, pnum, offset, read);
 		ubi_dbg_dump_stack();
+
+		/*
+		 * The driver should never return -EBADMSG if it failed to read
+		 * all the requested data. But some buggy drivers might do
+		 * this, so we change it to -EIO.
+		 */
+		if (read != len && err == -EBADMSG) {
+			ubi_assert(0);
+			err = -EIO;
+		}
 	} else {
 		ubi_assert(len == read);