[PATCH 6.19 490/781] cxl: Fix premature commit_end increment on decoder commit failure

Greg Kroah-Hartman
2026-02-25T01:36:53Z

From: Yuxiong Wang <yuxiong.wang@linux.alibaba.com>

[ Upstream commit 7b6f9d9b1ea05c9c22570126547c780e8c6c3f62 ]

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: 176baefb2eb5 ("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>
---
drivers/cxl/core/hdm.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index a7ad730763e85..bc4b0c8607258 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -844,14 +844,13 @@ static int cxl_decoder_commit(struct cxl_decoder *cxld)
scoped_guard(rwsem_read, &cxl_rwsem.dpa)
setup_hw_decoder(cxld, hdm);

- port->commit_end++;
rc = cxld_await_commit(hdm, cxld->id);
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;
--
2.51.0