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Message-Id: <20230724110204.46285-3-andriy.shevchenko@linux.intel.com>
Date: Mon, 24 Jul 2023 14:02:02 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Jonathan Cameron <jic23@...nel.org>,
Lars-Peter Clausen <lars@...afoo.de>,
Uwe Kleine-König
<u.kleine-koenig@...gutronix.de>,
Kees Cook <keescook@...omium.org>, Nuno Sa <nuno.sa@...log.com>
Subject: [PATCH v3 2/4] iio: core: Add opaque_struct_size() helper and use it
Introduce opaque_struct_size() helper, which may be moved
to overflow.h in the future, and use it in the IIO core.
Potential users could be (among possible others):
__spi_alloc_controller() in drivers/spi/spi.c
alloc_netdev_mqs in net/core/dev.c
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Cc: Kees Cook <keescook@...omium.org>
Reviewed-by: Nuno Sa <nuno.sa@...log.com>
---
drivers/iio/industrialio-core.c | 28 ++++++++++++++++++++--------
1 file changed, 20 insertions(+), 8 deletions(-)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index b153adc5bc84..118ca6b59504 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1607,6 +1607,24 @@ const struct device_type iio_device_type = {
.release = iio_dev_release,
};
+/**
+ * opaque_struct_size() - Calculate size of opaque structure with trailing aligned data.
+ * @p: Pointer to the opaque structure.
+ * @a: Alignment in bytes before trailing data.
+ * @s: Data size in bytes (preferred not to be 0).
+ *
+ * Calculates size of memory needed for structure of @p followed by
+ * the aligned data of size @s.
+ *
+ * Note, when @s is 0, the alignment @a is added to the sizeof(*(@p))
+ * and the result, depending on the @a, may be way off the initial size.
+ *
+ * Returns: Number of bytes needed or SIZE_MAX on overflow.
+ */
+#define opaque_struct_size(p, a, s) size_add(ALIGN(sizeof(*(p)), (a)), (s))
+
+#define opaque_struct_data(p, a) PTR_ALIGN((void *)((p) + 1), (a))
+
/**
* iio_device_alloc() - allocate an iio_dev from a driver
* @parent: Parent device.
@@ -1618,19 +1636,13 @@ struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv)
struct iio_dev *indio_dev;
size_t alloc_size;
- alloc_size = sizeof(struct iio_dev_opaque);
- if (sizeof_priv) {
- alloc_size = ALIGN(alloc_size, IIO_DMA_MINALIGN);
- alloc_size += sizeof_priv;
- }
-
+ alloc_size = opaque_struct_size(iio_dev_opaque, IIO_DMA_MINALIGN, sizeof_priv);
iio_dev_opaque = kzalloc(alloc_size, GFP_KERNEL);
if (!iio_dev_opaque)
return NULL;
indio_dev = &iio_dev_opaque->indio_dev;
- indio_dev->priv = (char *)iio_dev_opaque +
- ALIGN(sizeof(struct iio_dev_opaque), IIO_DMA_MINALIGN);
+ indio_dev->priv = opaque_struct_data(iio_dev_opaque, IIO_DMA_MINALIGN);
indio_dev->dev.parent = parent;
indio_dev->dev.type = &iio_device_type;
--
2.40.0.1.gaa8946217a0b
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