qed*: Fix link indication race

Driver changes the link properties via communication with
the management firmware, and re-reads the resulting link status
when it receives an indication that the link has changed.
However, there are certain scenarios where such indications
might be missing, and so driver also re-reads the current link
results without attention in several places. Specifically, it
does so during load and when resetting the link.

This creates a race where driver might reflect incorrect
link status - e.g., when explicit reading of the link status is
switched by attention with the changed configuration.

Correct this flow by a lock syncronizing the handling of the
link indications [both explicit requests and attention].

Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/net/ethernet/qlogic/qed/qed_mcp.h b/drivers/net/ethernet/qlogic/qed/qed_mcp.h
index 0792224ac219..368e88de146c 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_mcp.h
+++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.h
@@ -485,7 +485,13 @@ int qed_mcp_bist_nvm_test_get_image_att(struct qed_hwfn *p_hwfn,
 #define MFW_PORT(_p_hwfn)       ((_p_hwfn)->abs_pf_id %	\
 				 ((_p_hwfn)->cdev->num_ports_in_engines * 2))
 struct qed_mcp_info {
+	/* Spinlock used for protecting the access to the MFW mailbox */
 	spinlock_t				lock;
+
+	/* Spinlock used for syncing SW link-changes and link-changes
+	 * originating from attention context.
+	 */
+	spinlock_t				link_lock;
 	bool					block_mb_sending;
 	u32					public_base;
 	u32					drv_mb_addr;