sfc: Remove unnecessary use of atomic_t

We can set, get and compare-and-exchange without using atomic_t.
Change efx_mcdi_iface::state to the enum type we really wanted it to
be.

Suggested-by: David Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

2 files changed, 13 insertions, 17 deletions

diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c
index 89bc194a55f7..c616fb52d1d5 100644
--- a/drivers/net/ethernet/sfc/mcdi.c
+++ b/drivers/net/ethernet/sfc/mcdi.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/delay.h>
+#include <asm/cmpxchg.h>
 #include "net_driver.h"
 #include "nic.h"
 #include "io.h"
@@ -53,7 +54,7 @@ int efx_mcdi_init(struct efx_nic *efx)
         mcdi = efx_mcdi(efx);
         init_waitqueue_head(&mcdi->wq);
         spin_lock_init(&mcdi->iface_lock);
-        atomic_set(&mcdi->state, MCDI_STATE_QUIESCENT);
+        mcdi->state = MCDI_STATE_QUIESCENT;
         mcdi->mode = MCDI_MODE_POLL;
 
         (void) efx_mcdi_poll_reboot(efx);
@@ -65,8 +66,7 @@ int efx_mcdi_init(struct efx_nic *efx)
 
 void efx_mcdi_fini(struct efx_nic *efx)
 {
-        BUG_ON(efx->mcdi &&
-               atomic_read(&efx->mcdi->iface.state) != MCDI_STATE_QUIESCENT);
+        BUG_ON(efx->mcdi && efx->mcdi->iface.state != MCDI_STATE_QUIESCENT);
         kfree(efx->mcdi);
 }
 
@@ -78,7 +78,7 @@ static void efx_mcdi_send_request(struct efx_nic *efx, unsigned cmd,
         size_t hdr_len;
         u32 xflags, seqno;
 
-        BUG_ON(atomic_read(&mcdi->state) == MCDI_STATE_QUIESCENT);
+        BUG_ON(mcdi->state == MCDI_STATE_QUIESCENT);
 
         /* Serialise with efx_mcdi_ev_cpl() and efx_mcdi_ev_death() */
         spin_lock_bh(&mcdi->iface_lock);
@@ -258,20 +258,17 @@ static void efx_mcdi_acquire(struct efx_mcdi_iface *mcdi)
         /* Wait until the interface becomes QUIESCENT and we win the race
          * to mark it RUNNING. */
         wait_event(mcdi->wq,
-                   atomic_cmpxchg(&mcdi->state,
-                                  MCDI_STATE_QUIESCENT,
-                                  MCDI_STATE_RUNNING)
-                   == MCDI_STATE_QUIESCENT);
+                   cmpxchg(&mcdi->state,
+                           MCDI_STATE_QUIESCENT, MCDI_STATE_RUNNING) ==
+                   MCDI_STATE_QUIESCENT);
 }
 
 static int efx_mcdi_await_completion(struct efx_nic *efx)
 {
         struct efx_mcdi_iface *mcdi = efx_mcdi(efx);
 
-        if (wait_event_timeout(
-                    mcdi->wq,
-                    atomic_read(&mcdi->state) == MCDI_STATE_COMPLETED,
-                    MCDI_RPC_TIMEOUT) == 0)
+        if (wait_event_timeout(mcdi->wq, mcdi->state == MCDI_STATE_COMPLETED,
+                               MCDI_RPC_TIMEOUT) == 0)
                 return -ETIMEDOUT;
 
         /* Check if efx_mcdi_set_mode() switched us back to polled completions.
@@ -296,9 +293,8 @@ static bool efx_mcdi_complete(struct efx_mcdi_iface *mcdi)
          * QUIESCENT. [A subsequent invocation would increment seqno, so would
          * have failed the seqno check].
          */
-        if (atomic_cmpxchg(&mcdi->state,
-                           MCDI_STATE_RUNNING,
-                           MCDI_STATE_COMPLETED) == MCDI_STATE_RUNNING) {
+        if (cmpxchg(&mcdi->state, MCDI_STATE_RUNNING, MCDI_STATE_COMPLETED) ==
+            MCDI_STATE_RUNNING) {
                 wake_up(&mcdi->wq);
                 return true;
         }
@@ -308,7 +304,7 @@ static bool efx_mcdi_complete(struct efx_mcdi_iface *mcdi)
 
 static void efx_mcdi_release(struct efx_mcdi_iface *mcdi)
 {
-        atomic_set(&mcdi->state, MCDI_STATE_QUIESCENT);
+        mcdi->state = MCDI_STATE_QUIESCENT;
         wake_up(&mcdi->wq);
 }
 
diff --git a/drivers/net/ethernet/sfc/mcdi.h b/drivers/net/ethernet/sfc/mcdi.h
index 303d9e88a27f..6c0363a2abdf 100644
--- a/drivers/net/ethernet/sfc/mcdi.h
+++ b/drivers/net/ethernet/sfc/mcdi.h
@@ -46,7 +46,7 @@ enum efx_mcdi_mode {
  * @resp_data_len: Response data (SDU or error) length
  */
 struct efx_mcdi_iface {
-        atomic_t state;
+        enum efx_mcdi_state state;
         enum efx_mcdi_mode mode;
         wait_queue_head_t wq;
         spinlock_t iface_lock;