github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-09-23 22:14:03 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

cxl/port: Restart port enumeration when a sibling adds the dport first

Browse Source 
Endpoint probes can race while enumerating a shared switch. If a
sibling probe adds the dport first, the losing probe finds the dport
already present, gets -EBUSY, and fails to enumerate the endpoint.

Treat this race the same as the existing port-created case by
restarting the port walk, allowing it to find the existing dport
and continue enumeration.

This race was discovered while testing a cxl_test mixed-granularity
topology, where twelve endpoints behind shared switches are probed in
parallel during module load.

Fixes: 4f06d81e7c ("cxl: Defer dport allocation for switch ports")
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Tested-by: Li Ming <ming.li@zohomail.com>
Reviewed-by: Li Ming <ming.li@zohomail.com>
Link: https://patch.msgid.link/20260714020438.1822669-1-alison.schofield@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
This commit is contained in:
Alison Schofield 2026-07-13 19:04:35 -07:00 committed by Dave Jiang
parent 77b814c183
commit a623128bc2
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/cxl/core/port.c
View File

@ -1749,8 +1749,8 @@ static int add_port_attach_ep(struct cxl_memdev *cxlmd,
parent_dport, uport_dev,
dport_dev);
if (IS_ERR(dport)) {
/* Port already exists, restart iteration */
if (PTR_ERR(dport) == -EAGAIN)
/* Port or dport already exists, restart iteration */
if (PTR_ERR(dport) == -EAGAIN || PTR_ERR(dport) == -EBUSY)
return 0;
return PTR_ERR(dport);
}