linux-kernel - [tip: locking/core] orinoco_usb: Use the regular completion interfaces

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Message-ID: <158480603181.28353.15012270806617085954.tip-bot2@tip-bot2>
Date:   Sat, 21 Mar 2020 15:53:51 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        x86 <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: [tip: locking/core] orinoco_usb: Use the regular completion interfaces

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     9fe114ce0371223d2a0490f0aa52b8f108d92f37
Gitweb:        https://git.kernel.org/tip/9fe114ce0371223d2a0490f0aa52b8f108d92f37
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Sat, 21 Mar 2020 12:25:48 +01:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Sat, 21 Mar 2020 16:00:20 +01:00

orinoco_usb: Use the regular completion interfaces

The completion usage in this driver is interesting:

  - it uses a magic complete function which according to the comment was
    implemented by invoking complete() four times in a row because
    complete_all() was not exported at that time.

  - it uses an open coded wait/poll which checks completion:done. Only one wait
    side (device removal) uses the regular wait_for_completion() interface.

The rationale behind this is to prevent that wait_for_completion() consumes
completion::done which would prevent that all waiters are woken. This is not
necessary with complete_all() as that sets completion::done to UINT_MAX which
is left unmodified by the woken waiters.

Replace the magic complete function with complete_all() and convert the
open coded wait/poll to regular completion interfaces.

This changes the wait to exclusive wait mode. But that does not make any
difference because the wakers use complete_all() which ignores the
exclusive mode.

Reported-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Link: https://lkml.kernel.org/r/20200321113241.150783464@linutronix.de
---
 drivers/net/wireless/intersil/orinoco/orinoco_usb.c | 21 ++----------
 1 file changed, 5 insertions(+), 16 deletions(-)

diff --git a/drivers/net/wireless/intersil/orinoco/orinoco_usb.c b/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
index e753f43..0e42de2 100644
--- a/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
+++ b/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
@@ -365,17 +365,6 @@ static struct request_context *ezusb_alloc_ctx(struct ezusb_priv *upriv,
 	return ctx;
 }
 
-
-/* Hopefully the real complete_all will soon be exported, in the mean
- * while this should work. */
-static inline void ezusb_complete_all(struct completion *comp)
-{
-	complete(comp);
-	complete(comp);
-	complete(comp);
-	complete(comp);
-}
-
 static void ezusb_ctx_complete(struct request_context *ctx)
 {
 	struct ezusb_priv *upriv = ctx->upriv;
@@ -409,7 +398,7 @@ static void ezusb_ctx_complete(struct request_context *ctx)
 
 			netif_wake_queue(dev);
 		}
-		ezusb_complete_all(&ctx->done);
+		complete_all(&ctx->done);
 		ezusb_request_context_put(ctx);
 		break;
 
@@ -419,7 +408,7 @@ static void ezusb_ctx_complete(struct request_context *ctx)
 			/* This is normal, as all request contexts get flushed
 			 * when the device is disconnected */
 			err("Called, CTX not terminating, but device gone");
-			ezusb_complete_all(&ctx->done);
+			complete_all(&ctx->done);
 			ezusb_request_context_put(ctx);
 			break;
 		}
@@ -690,11 +679,11 @@ static void ezusb_req_ctx_wait(struct ezusb_priv *upriv,
 			 * get the chance to run themselves. So we make sure
 			 * that we don't sleep for ever */
 			int msecs = DEF_TIMEOUT * (1000 / HZ);
-			while (!ctx->done.done && msecs--)
+
+			while (!try_wait_for_completion(&ctx->done) && msecs--)
 				udelay(1000);
 		} else {
-			wait_event_interruptible(ctx->done.wait,
-						 ctx->done.done);
+			wait_for_completion(&ctx->done);
 		}
 		break;
 	default: