AZL-51219

In the Linux kernel, the following vulnerability has been resolved:

block: fix potential invalid pointer dereference in blkaddpartition

The blkaddpartition() function initially used a single if-condition (ISERR(part)) to check for errors when adding a partition. This was modified to handle the specific case of -ENXIO separately, allowing the function to proceed without logging the error in this case. However, this change unintentionally left a path where mdautodetect_dev() could be called without confirming that part is a valid pointer.

This commit separates the error handling logic by splitting the initial if-condition, improving code readability and handling specific error scenarios explicitly. The function now distinguishes the general error case from -ENXIO without altering the existing behavior of mdautodetectdev() calls.