[PATCH 24/28] EDAC/thunderx: Fix stale error context in thunderx_l2c_threaded_isr()

[Bill Wendling <morbo@google.com>]

thunderx_l2c_threaded_isr() computes "tail" and "ctx" once before entering
the loop that drains the L2C error ring, and never updates them on
subsequent iterations. When multiple errors are queued, every iteration
reports the first ring entry rather than advancing through the ring,
causing subsequent hardware errors in a batch to go unreported.

Recompute "tail" and "ctx" at the start of each loop iteration, matching
the sibling thunderx_ocx_com_threaded_isr() and
thunderx_ocx_lnk_threaded_isr() handlers.

Fixes: 41003396f932 ("EDAC, thunderx: Add Cavium ThunderX EDAC driver")
Signed-off-by: Bill Wendling <morbo@google.com>
---
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---
 drivers/edac/thunderx_edac.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c
index 9c0a1e48f96f..e7c335ca0c36 100644
--- a/drivers/edac/thunderx_edac.c
+++ b/drivers/edac/thunderx_edac.c
@@ -1880,6 +1880,9 @@ static irqreturn_t thunderx_l2c_threaded_isr(int irq, void *irq_id)
 
 	while (CIRC_CNT(l2c->ring_head, l2c->ring_tail,
 			ARRAY_SIZE(l2c->err_ctx))) {
+		tail = ring_pos(l2c->ring_tail, ARRAY_SIZE(l2c->err_ctx));
+		ctx = &l2c->err_ctx[tail];
+
 		snprintf(msg, L2C_MESSAGE_SIZE,
 			 "%s: %s: %016llx, %s: %016llx",
 			 l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int,
-- 
2.55.0.1032.g73a4cd73de-goog