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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ulf Hansson <ulf.hansson@linaro.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0854/1017] mmc: host: Return an error when ->enable_sdio_irq() ops is missing
Date:   Tue,  5 Apr 2022 09:29:27 +0200
Message-Id: <20220405070419.586137766@linuxfoundation.org>
In-Reply-To: <20220405070354.155796697@linuxfoundation.org>
References: <20220405070354.155796697@linuxfoundation.org>
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From: Ulf Hansson <ulf.hansson@linaro.org>

[ Upstream commit d6c9219ca1139b74541b2a98cee47a3426d754a9 ]

Even if the current WARN() notifies the user that something is severely
wrong, we can still end up in a PANIC() when trying to invoke the missing
->enable_sdio_irq() ops. Therefore, let's also return an error code and
prevent the host from being added.

While at it, move the code into a separate function to prepare for
subsequent changes and for further host caps validations.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20220303165142.129745-1-ulf.hansson@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/mmc/core/host.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index cf140f4ec864..d739e2b631fe 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -588,6 +588,16 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 
 EXPORT_SYMBOL(mmc_alloc_host);
 
+static int mmc_validate_host_caps(struct mmc_host *host)
+{
+	if (host->caps & MMC_CAP_SDIO_IRQ && !host->ops->enable_sdio_irq) {
+		dev_warn(host->parent, "missing ->enable_sdio_irq() ops\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 /**
  *	mmc_add_host - initialise host hardware
  *	@host: mmc host
@@ -600,8 +610,9 @@ int mmc_add_host(struct mmc_host *host)
 {
 	int err;
 
-	WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) &&
-		!host->ops->enable_sdio_irq);
+	err = mmc_validate_host_caps(host);
+	if (err)
+		return err;
 
 	err = device_add(&host->class_dev);
 	if (err)
-- 
2.34.1