linux-kernel - [PATCH] mmc: cqhci: Fix a tiny potential memory leak on error condition

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Date:   Tue, 15 Jan 2019 16:24:38 -0800
From:   Alamy Liu <alamy.liu@...il.com>
To:     Venkat Gopalakrishnan <venkatg@...eaurora.org>
Cc:     Ulf Hansson <ulf.hansson@...aro.org>,
        linux-mmc@...r.kernel.org (open list:MULTIMEDIA CARD (MMC), SECURE
        DIGITAL (SD) AND...), linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] mmc: cqhci: Fix a tiny potential memory leak on error condition

In the error case:
   either cq_host->desc_base
       or cq_host->trans_desc_base
might have been granted memory successfully.

The value of mmc_host->cqe_enabled stays 'false'.
Thus, cqhci_disable (mmc_cqe_ops->cqe_disable) won't be called to
free the memory.
Also, cqhci_disable() is designed to disable and free all resources,
not suitable to handle this corner case.

Signed-off-by: Alamy Liu <alamy.liu@...il.com>
---
 drivers/mmc/host/cqhci.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/cqhci.c b/drivers/mmc/host/cqhci.c
index 974997b6cb..58ad8cd613 100644
--- a/drivers/mmc/host/cqhci.c
+++ b/drivers/mmc/host/cqhci.c
@@ -223,7 +223,7 @@ static int cqhci_host_alloc_tdl(struct cqhci_host *cq_host)
 					      &cq_host->trans_desc_dma_base,
 					      GFP_KERNEL);
 	if (!cq_host->desc_base || !cq_host->trans_desc_base)
-		return -ENOMEM;
+		goto err_free_dma;
 
 	pr_debug("%s: cqhci: desc-base: 0x%p trans-base: 0x%p\n desc_dma 0x%llx trans_dma: 0x%llx\n",
 		 mmc_hostname(cq_host->mmc), cq_host->desc_base, cq_host->trans_desc_base,
@@ -234,6 +234,24 @@ static int cqhci_host_alloc_tdl(struct cqhci_host *cq_host)
 		setup_trans_desc(cq_host, i);
 
 	return 0;
+
+err_free_dma:
+	if (cq_host->desc_base) {
+		dmam_free_coherent(mmc_dev(cq_host->mmc), cq_host->desc_size,
+				   cq_host->desc_base,
+				   cq_host->desc_dma_base);
+		cq_host->desc_base = NULL;
+		cq_host->desc_dma_base = 0;
+	}
+	if (cq_host->trans_desc_base) {
+		dmam_free_coherent(mmc_dev(cq_host->mmc), cq_host->data_size,
+				   cq_host->trans_desc_base,
+				   cq_host->trans_desc_dma_base);
+		cq_host->trans_desc_base = NULL;
+		cq_host->trans_desc_dma_base = 0;
+	}
+
+	return -ENOMEM;
 }
 
 static void __cqhci_enable(struct cqhci_host *cq_host)
-- 
2.17.1