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| author | Jan Höppner <hoeppner@linux.ibm.com> | 2019-12-19 09:43:50 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-12-20 19:52:01 +0100 |
| commit | dd4b3c83b9efac10d48a94c61372119fc555a077 (patch) | |
| tree | e62489927db3e2f4cf5caa0d302e13e98d3dccfa /drivers/s390/cio/device_ops.c | |
| parent | block: Fix a lockdep complaint triggered by request queue flushing (diff) | |
| download | linux-dd4b3c83b9efac10d48a94c61372119fc555a077.tar.xz linux-dd4b3c83b9efac10d48a94c61372119fc555a077.zip | |
s390/dasd/cio: Interpret ccw_device_get_mdc return value correctly
The max data count (mdc) is an unsigned 16-bit integer value as per AR
documentation and is received via ccw_device_get_mdc() for a specific
path mask from the CIO layer. The function itself also always returns a
positive mdc value or 0 in case mdc isn't supported or couldn't be
determined.
Though, the comment for this function describes a negative return value
to indicate failures.
As a result, the DASD device driver interprets the return value of
ccw_device_get_mdc() incorrectly. The error case is essentially a dead
code path.
To fix this behaviour, check explicitly for a return value of 0 and
change the comment for ccw_device_get_mdc() accordingly.
This fix merely enables the error code path in the DASD functions
get_fcx_max_data() and verify_fcx_max_data(). The actual functionality
stays the same and is still correct.
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/s390/cio/device_ops.c')
| -rw-r--r-- | drivers/s390/cio/device_ops.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c index 65841af15748..ccecf6b9504e 100644 --- a/drivers/s390/cio/device_ops.c +++ b/drivers/s390/cio/device_ops.c @@ -635,7 +635,7 @@ EXPORT_SYMBOL(ccw_device_tm_start_timeout); * @mask: mask of paths to use * * Return the number of 64K-bytes blocks all paths at least support - * for a transport command. Return values <= 0 indicate failures. + * for a transport command. Return value 0 indicates failure. */ int ccw_device_get_mdc(struct ccw_device *cdev, u8 mask) { |