linux-kernel - [PATCH v1 1/1] mmc: mmc_spi: Simplify busy loop in mmc_spi

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Message-Id: <20210623101731.87885-1-andriy.shevchenko@linux.intel.com>
Date:   Wed, 23 Jun 2021 13:17:31 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Ulf Hansson <ulf.hansson@...aro.org>
Subject: [PATCH v1 1/1] mmc: mmc_spi: Simplify busy loop in mmc_spi_skip()

Infinite loops are hard to read and understand because of
hidden main loop condition. Simplify such one in mmc_spi_skip().

Using schedule() to schedule (and be friendly to others)
is discouraged and cond_resched() should be used instead.
Hence, replace schedule() with cond_resched() at the same
time.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 drivers/mmc/host/mmc_spi.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 65c65bb5737f..a1bcde3395a6 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -180,7 +180,7 @@ static int mmc_spi_skip(struct mmc_spi_host *host, unsigned long timeout,
 	u8 *cp = host->data->status;
 	unsigned long start = jiffies;
 
-	while (1) {
+	do {
 		int		status;
 		unsigned	i;
 
@@ -193,16 +193,9 @@ static int mmc_spi_skip(struct mmc_spi_host *host, unsigned long timeout,
 				return cp[i];
 		}
 
-		if (time_is_before_jiffies(start + timeout))
-			break;
-
-		/* If we need long timeouts, we may release the CPU.
-		 * We use jiffies here because we want to have a relation
-		 * between elapsed time and the blocking of the scheduler.
-		 */
-		if (time_is_before_jiffies(start + 1))
-			schedule();
-	}
+		/* If we need long timeouts, we may release the CPU */
+		cond_resched();
+	} while (time_is_after_jiffies(start + timeout));
 	return -ETIMEDOUT;
 }
 
-- 
2.30.2