6.8-stable review patch. If anyone has any objections, please let me know.
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From: Dan Williams dan.j.williams@intel.com
[ Upstream commit 4b759dd5765503bd466defac7d93aca14c23a15d ]
A recent change to cxl_mem_get_records_log() [1] highlighted a subtle nuance of looping calls to cxl_internal_send_cmd(), i.e. that cxl_internal_send_cmd() modifies the 'size_out' member of the @mbox_cmd argument. That mechanism is useful for communicating underflow, but it is unwanted when reusing @mbox_cmd for a subsequent submission. It turns out that cxl_xfer_log() avoids this scenario by always redefining @mbox_cmd each iteration.
Update cxl_mem_get_records_log() and cxl_mem_get_poison() to follow the same style as cxl_xfer_log(), i.e. re-define @mbox_cmd each iteration. The cxl_mem_get_records_log() change is just a style fixup, but the cxl_mem_get_poison() change is a potential fix, per Alison [2]:
Poison list retrieval can hit this case if the MORE flag is set and a follow on read of the list delivers more records than the previous read. ie. device gives one record, sets the _MORE flag, then gives 5.
Not an urgent fix since this behavior has not been seen in the wild, but worth tracking as a fix.
Cc: Kwangjin Ko kwangjin.ko@sk.com Cc: Alison Schofield alison.schofield@intel.com Fixes: ed83f7ca398b ("cxl/mbox: Add GET_POISON_LIST mailbox command") Link: http://lore.kernel.org/r/20240402081404.1106-2-kwangjin.ko@sk.com [1] Link: http://lore.kernel.org/r/ZhAhAL/GOaWFrauw@aschofie-mobl2 [2] Signed-off-by: Dan Williams dan.j.williams@intel.com Reviewed-by: Ira Weiny ira.weiny@intel.com Reviewed-by: Alison Schofield alison.schofield@intel.com Link: https://lore.kernel.org/r/171235441633.2716581.12330082428680958635.stgit@dw... Signed-off-by: Dave Jiang dave.jiang@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cxl/core/mbox.c | 38 +++++++++++++++++--------------------- 1 file changed, 17 insertions(+), 21 deletions(-)
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index f0f54aeccc872..65185c9fa0013 100644 --- a/drivers/cxl/core/mbox.c +++ b/drivers/cxl/core/mbox.c @@ -946,25 +946,22 @@ static void cxl_mem_get_records_log(struct cxl_memdev_state *mds, struct cxl_memdev *cxlmd = mds->cxlds.cxlmd; struct device *dev = mds->cxlds.dev; struct cxl_get_event_payload *payload; - struct cxl_mbox_cmd mbox_cmd; u8 log_type = type; u16 nr_rec;
mutex_lock(&mds->event.log_lock); payload = mds->event.buf;
- mbox_cmd = (struct cxl_mbox_cmd) { - .opcode = CXL_MBOX_OP_GET_EVENT_RECORD, - .payload_in = &log_type, - .size_in = sizeof(log_type), - .payload_out = payload, - .min_out = struct_size(payload, records, 0), - }; - do { int rc, i; - - mbox_cmd.size_out = mds->payload_size; + struct cxl_mbox_cmd mbox_cmd = (struct cxl_mbox_cmd) { + .opcode = CXL_MBOX_OP_GET_EVENT_RECORD, + .payload_in = &log_type, + .size_in = sizeof(log_type), + .payload_out = payload, + .size_out = mds->payload_size, + .min_out = struct_size(payload, records, 0), + };
rc = cxl_internal_send_cmd(mds, &mbox_cmd); if (rc) { @@ -1297,7 +1294,6 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len, struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds); struct cxl_mbox_poison_out *po; struct cxl_mbox_poison_in pi; - struct cxl_mbox_cmd mbox_cmd; int nr_records = 0; int rc;
@@ -1309,16 +1305,16 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len, pi.offset = cpu_to_le64(offset); pi.length = cpu_to_le64(len / CXL_POISON_LEN_MULT);
- mbox_cmd = (struct cxl_mbox_cmd) { - .opcode = CXL_MBOX_OP_GET_POISON, - .size_in = sizeof(pi), - .payload_in = &pi, - .size_out = mds->payload_size, - .payload_out = po, - .min_out = struct_size(po, record, 0), - }; - do { + struct cxl_mbox_cmd mbox_cmd = (struct cxl_mbox_cmd){ + .opcode = CXL_MBOX_OP_GET_POISON, + .size_in = sizeof(pi), + .payload_in = &pi, + .size_out = mds->payload_size, + .payload_out = po, + .min_out = struct_size(po, record, 0), + }; + rc = cxl_internal_send_cmd(mds, &mbox_cmd); if (rc) break;