[patch V2 04/15] orinoco_usb: Use the regular completion interfaces

From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>, Will Deacon <will@kernel.org>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Joel Fernandes <joel@joelfernandes.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Kalle Valo <kvalo@codeaurora.org>,
	"David S. Miller" <davem@davemloft.net>,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
	Logan Gunthorpe <logang@deltatee.com>,
	Kurt Schwemmer <kurt.schwemmer@microsemi.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, Felipe Balbi <balbi@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-usb@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Arnd Bergmann <arnd@arndb.de>,
	linuxppc-dev@lists.ozlabs.org
Subject: [patch V2 04/15] orinoco_usb: Use the regular completion interfaces
Date: Wed, 18 Mar 2020 21:43:06 +0100	[thread overview]
Message-ID: <20200318204407.793899611@linutronix.de> (raw)
In-Reply-To: 20200318204302.693307984@linutronix.de

From: Thomas Gleixner <tglx@linutronix.de>

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@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
---
V2: New patch to avoid conversion to swait functions later.
---
 drivers/net/wireless/intersil/orinoco/orinoco_usb.c |   21 ++++----------------
 1 file changed, 5 insertions(+), 16 deletions(-)

--- 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_all
 	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 re
 
 			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 re
 			/* 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 ez
 			 * 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:

