cxl: Fix premature commit_end increment on decoder commit failure

[ Upstream commit 7b6f9d9 ]

In cxl_decoder_commit(), commit_end is incremented before verifying
whether the commit succeeded, and the CXL_DECODER_F_ENABLE bit in
cxld->flags is only set after a successful commit. As a result, if the
commit fails, commit_end has been incremented and cxld->reset() has no
effect since the flag is not set, so commit_end remains incorrectly
incremented. The inconsistency between commit_end and CXL_DECODER_F_ENABLE
causes failure during subsequent either commit or reset operations.

Fix this by incrementing commit_end only after confirming the commit
succeeded. Also, remove the ineffective cxld->reset() call. According to
CXL Spec r4.0 8.2.4.20.12 Committing Decoder Programming, since
cxld_await_commit() has cleared the decoder commit bit on failure, no
additional reset is required.

[dj: Fixed commit log 80 char wrapping. ]
[dj: Fix "Fixes" tag to correct hash length. ]
[dj: Change spec to r4.0. ]

Fixes: 176baef ("cxl/hdm: Commit decoder state to hardware")
Signed-off-by: Yuxiong Wang <yuxiong.wang@linux.alibaba.com>
Acked-by: Huang Ying <ying.huang@linux.alibaba.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Link: https://patch.msgid.link/20260129064552.31180-1-yuxiong.wang@linux.alibaba.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Yuxiong Wang

drivers/cxl/core/hdm.c

@@ -628,15 +628,14 @@ static int cxl_decoder_commit(struct cxl_decoder *cxld)
 	writel(ctrl, hdm + CXL_HDM_DECODER0_CTRL_OFFSET(id));
 	up_read(&cxl_dpa_rwsem);
 
-	port->commit_end++;
 	rc = cxld_await_commit(hdm, cxld->id);
 err:
 	if (rc) {
 		dev_dbg(&port->dev, "%s: error %d committing decoder\n",
 			dev_name(&cxld->dev), rc);
-		cxld->reset(cxld);
 		return rc;
 	}
+	port->commit_end++;
 	cxld->flags |= CXL_DECODER_F_ENABLE;
 
 	return 0;