iio: proximity: isl29501: Fix return type of isl29501_register_writegrafted

isl29501_register_write() was returning a u32 instead of an int.
Since the function returns negative error codes (such as -ERANGE or
return values from i2c_smbus_write_byte_data()), returning an unsigned
integer type prevents callers from correctly checking for negative error
conditions.

Fix this by changing the function return type from u32 to int.

This was found through manual code review.

Fixes: 1c28799257bc ("iio: light: isl29501: Add support for the ISL29501 ToF sensor.")
Signed-off-by: Salah Triki <salah.triki@gmail.com>
Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

1 files changed, 129 insertions, 0 deletions

diff --git a/lib/vdso/datastore.c b/lib/vdso/datastore.c
new file mode 100644
index 000000000..1426bf4e0
--- /dev/null
+++ b/lib/vdso/datastore.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/time_namespace.h>
+#include <linux/types.h>
+#include <linux/vdso_datastore.h>
+#include <vdso/datapage.h>
+
+static u8 vdso_initdata[VDSO_NR_PAGES * PAGE_SIZE] __aligned(PAGE_SIZE) __initdata = {};
+
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
+struct vdso_time_data *vdso_k_time_data __ro_after_init =
+	(void *)&vdso_initdata[VDSO_TIME_PAGE_OFFSET * PAGE_SIZE];
+
+static_assert(sizeof(struct vdso_time_data) <= PAGE_SIZE);
+#endif /* CONFIG_GENERIC_GETTIMEOFDAY */
+
+#ifdef CONFIG_VDSO_GETRANDOM
+struct vdso_rng_data *vdso_k_rng_data __ro_after_init =
+	(void *)&vdso_initdata[VDSO_RNG_PAGE_OFFSET * PAGE_SIZE];
+
+static_assert(sizeof(struct vdso_rng_data) <= PAGE_SIZE);
+#endif /* CONFIG_VDSO_GETRANDOM */
+
+#ifdef CONFIG_ARCH_HAS_VDSO_ARCH_DATA
+struct vdso_arch_data *vdso_k_arch_data __ro_after_init =
+	(void *)&vdso_initdata[VDSO_ARCH_PAGES_START * PAGE_SIZE];
+#endif /* CONFIG_ARCH_HAS_VDSO_ARCH_DATA */
+
+static struct page *vdso_data_pages __ro_after_init;
+
+void __init vdso_setup_data_pages(void)
+{
+	unsigned int order = get_order(VDSO_NR_PAGES * PAGE_SIZE);
+
+	/*
+	 * Allocate the data pages dynamically. SPARC does not support mapping
+	 * static pages to be mapped into userspace.
+	 * It is also a requirement for mlockall() support.
+	 *
+	 * Do not use folios. In time namespaces the pages are mapped in a different order
+	 * to userspace, which is not handled by the folio optimizations in finish_fault().
+	 */
+	vdso_data_pages = alloc_pages(GFP_KERNEL, order);
+	if (!vdso_data_pages)
+		panic("Unable to allocate VDSO storage pages");
+
+	/* The pages are mapped one-by-one into userspace and each one needs to be refcounted. */
+	split_page(vdso_data_pages, order);
+
+	/* Move the data already written by other subsystems to the new pages */
+	memcpy(page_address(vdso_data_pages), vdso_initdata, VDSO_NR_PAGES * PAGE_SIZE);
+
+	if (IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY))
+		vdso_k_time_data = page_address(vdso_data_pages + VDSO_TIME_PAGE_OFFSET);
+
+	if (IS_ENABLED(CONFIG_VDSO_GETRANDOM))
+		vdso_k_rng_data = page_address(vdso_data_pages + VDSO_RNG_PAGE_OFFSET);
+
+	if (IS_ENABLED(CONFIG_ARCH_HAS_VDSO_ARCH_DATA))
+		vdso_k_arch_data = page_address(vdso_data_pages + VDSO_ARCH_PAGES_START);
+}
+
+static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
+			     struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	struct page *page, *timens_page;
+
+	if (unlikely(vmf->flags & FAULT_FLAG_REMOTE))
+		return VM_FAULT_SIGBUS;
+
+	page = vdso_data_pages + vmf->pgoff;
+	timens_page = find_timens_vvar_page(vma);
+
+	switch (vmf->pgoff) {
+	case VDSO_TIME_PAGE_OFFSET:
+		if (!IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY) || !timens_page)
+			break;
+		/*
+		 * Fault in VVAR page too, since it will be accessed
+		 * to get clock data anyway.
+		 */
+		unsigned long addr;
+		vm_fault_t err;
+
+		addr = vmf->address + VDSO_TIMENS_PAGE_OFFSET * PAGE_SIZE;
+		err = vmf_insert_page(vma, addr, page);
+		if (unlikely(err & VM_FAULT_ERROR))
+			return err;
+		page = timens_page;
+		break;
+	case VDSO_TIMENS_PAGE_OFFSET:
+		/*
+		 * If a task belongs to a time namespace then a namespace
+		 * specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and
+		 * the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET
+		 * offset.
+		 * See also the comment near timens_setup_vdso_data().
+		 */
+		if (!IS_ENABLED(CONFIG_TIME_NS) || !timens_page)
+			break;
+		page = vdso_data_pages + VDSO_TIME_PAGE_OFFSET;
+		break;
+	case VDSO_RNG_PAGE_OFFSET:
+	case VDSO_ARCH_PAGES_START ... VDSO_ARCH_PAGES_END:
+		break;
+	default:
+		return VM_FAULT_SIGBUS;
+	}
+
+	get_page(page);
+	vmf->page = page;
+	return 0;
+}
+
+const struct vm_special_mapping vdso_vvar_mapping = {
+	.name	= "[vvar]",
+	.fault	= vvar_fault,
+};
+
+struct vm_area_struct *vdso_install_vvar_mapping(struct mm_struct *mm, unsigned long addr)
+{
+	return _install_special_mapping(mm, addr, VDSO_NR_PAGES * PAGE_SIZE,
+					VM_READ | VM_MAYREAD | VM_DONTDUMP |
+					VM_MIXEDMAP | VM_SEALED_SYSMAP,
+					&vdso_vvar_mapping);
+}