scsi: st: New session only when Unit Attention for new tape

jira LE-2289
Rebuild_History Non-Buildable kernel-4.18.0-553.36.1.el8_10
commit-author Kai Mäkisara <[email protected]>
commit a4550b2

Currently the code starts new tape session when any Unit Attention
(UA) is seen when opening the device. This leads to incorrectly
clearing pos_unknown when the UA is for reset. Set new session only
when the UA is for a new tape.

	Signed-off-by: Kai Mäkisara <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
	Reviewed-by: John Meneghini <[email protected]>
	Tested-by: John Meneghini <[email protected]>
	Signed-off-by: Martin K. Petersen <[email protected]>
(cherry picked from commit a4550b2)
	Signed-off-by: Jonathan Maple <[email protected]>

Author: PlaidCat

drivers/scsi/st.c

@@ -990,7 +990,10 @@ static int test_ready(struct scsi_tape *STp, int do_wait)
 			scode = cmdstatp->sense_hdr.sense_key;
 
 			if (scode == UNIT_ATTENTION) { /* New media? */
-				new_session = 1;
+				if (cmdstatp->sense_hdr.asc == 0x28) { /* New media */
+					new_session = 1;
+					DEBC_printk(STp, "New tape session.");
+				}
 				if (attentions < MAX_ATTENTIONS) {
 					attentions++;
 					continue;