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From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        Cornelia Huck <cohuck@redhat.com>
Subject: [PATCH v1 1/5] memremap: Check for size parameter
Date:   Fri, 15 Nov 2019 20:00:40 +0200
Message-Id: <20191115180044.83659-1-andriy.shevchenko@linux.intel.com>
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Sender: linux-kernel-owner@vger.kernel.org
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There is no use of memremap() to be called with size = 0.
Simple return NULL pointer and allow callers to drop this check.

Fixes: 92281dee825f ("arch: introduce memremap()")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 kernel/iomem.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/iomem.c b/kernel/iomem.c
index 62c92e43aa0d..bf7a5fc32760 100644
--- a/kernel/iomem.c
+++ b/kernel/iomem.c
@@ -74,6 +74,9 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
 				       IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
 	void *addr = NULL;
 
+	if (!size)
+		return NULL;
+
 	if (!flags)
 		return NULL;
 
-- 
2.24.0