[PATCH 2/2] treewide: Use sysfs_bin_attr_simple_read() helper

From: Lukas Wunner
Date: Sat Apr 06 2024 - 09:54:30 EST


Deduplicate ->read() callbacks of bin_attributes which are backed by a
simple buffer in memory:

Use the newly introduced sysfs_bin_attr_simple_read() helper instead,
either by referencing it directly or by declaring such bin_attributes
with BIN_ATTR_SIMPLE_RO() or BIN_ATTR_SIMPLE_ADMIN_RO().

Aside from a reduction of LoC, this shaves off a few bytes from vmlinux
(304 bytes on an x86_64 allyesconfig).

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
---
arch/powerpc/platforms/powernv/opal.c | 10 +--------
drivers/acpi/bgrt.c | 9 +-------
drivers/firmware/dmi_scan.c | 12 ++--------
drivers/firmware/efi/rci2-table.c | 10 +--------
drivers/gpu/drm/i915/gvt/firmware.c | 26 +++++-----------------
.../intel/int340x_thermal/int3400_thermal.c | 9 +-------
init/initramfs.c | 10 +--------
kernel/module/sysfs.c | 13 +----------
8 files changed, 14 insertions(+), 85 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 45dd77e..5d0f35b 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -792,14 +792,6 @@ static int __init opal_sysfs_init(void)
return 0;
}

-static ssize_t export_attr_read(struct file *fp, struct kobject *kobj,
- struct bin_attribute *bin_attr, char *buf,
- loff_t off, size_t count)
-{
- return memory_read_from_buffer(buf, count, &off, bin_attr->private,
- bin_attr->size);
-}
-
static int opal_add_one_export(struct kobject *parent, const char *export_name,
struct device_node *np, const char *prop_name)
{
@@ -826,7 +818,7 @@ static int opal_add_one_export(struct kobject *parent, const char *export_name,
sysfs_bin_attr_init(attr);
attr->attr.name = name;
attr->attr.mode = 0400;
- attr->read = export_attr_read;
+ attr->read = sysfs_bin_attr_simple_read;
attr->private = __va(vals[0]);
attr->size = vals[1];

diff --git a/drivers/acpi/bgrt.c b/drivers/acpi/bgrt.c
index e4fb9e2..d1d9c92 100644
--- a/drivers/acpi/bgrt.c
+++ b/drivers/acpi/bgrt.c
@@ -29,14 +29,7 @@
BGRT_SHOW(xoffset, image_offset_x);
BGRT_SHOW(yoffset, image_offset_y);

-static ssize_t image_read(struct file *file, struct kobject *kobj,
- struct bin_attribute *attr, char *buf, loff_t off, size_t count)
-{
- memcpy(buf, attr->private + off, count);
- return count;
-}
-
-static BIN_ATTR_RO(image, 0); /* size gets filled in later */
+static BIN_ATTR_SIMPLE_RO(image);

static struct attribute *bgrt_attributes[] = {
&bgrt_attr_version.attr,
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 015c95a..3d0f773 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -746,16 +746,8 @@ static void __init dmi_scan_machine(void)
pr_info("DMI not present or invalid.\n");
}

-static ssize_t raw_table_read(struct file *file, struct kobject *kobj,
- struct bin_attribute *attr, char *buf,
- loff_t pos, size_t count)
-{
- memcpy(buf, attr->private + pos, count);
- return count;
-}
-
-static BIN_ATTR(smbios_entry_point, S_IRUSR, raw_table_read, NULL, 0);
-static BIN_ATTR(DMI, S_IRUSR, raw_table_read, NULL, 0);
+static BIN_ATTR_SIMPLE_ADMIN_RO(smbios_entry_point);
+static BIN_ATTR_SIMPLE_ADMIN_RO(DMI);

static int __init dmi_init(void)
{
diff --git a/drivers/firmware/efi/rci2-table.c b/drivers/firmware/efi/rci2-table.c
index de1a9a1..4fd45d6 100644
--- a/drivers/firmware/efi/rci2-table.c
+++ b/drivers/firmware/efi/rci2-table.c
@@ -40,15 +40,7 @@ struct rci2_table_global_hdr {
static u32 rci2_table_len;
unsigned long rci2_table_phys __ro_after_init = EFI_INVALID_TABLE_ADDR;

-static ssize_t raw_table_read(struct file *file, struct kobject *kobj,
- struct bin_attribute *attr, char *buf,
- loff_t pos, size_t count)
-{
- memcpy(buf, attr->private + pos, count);
- return count;
-}
-
-static BIN_ATTR(rci2, S_IRUSR, raw_table_read, NULL, 0);
+static BIN_ATTR_SIMPLE_ADMIN_RO(rci2);

static u16 checksum(void)
{
diff --git a/drivers/gpu/drm/i915/gvt/firmware.c b/drivers/gpu/drm/i915/gvt/firmware.c
index 4dd52ac..5e66a26 100644
--- a/drivers/gpu/drm/i915/gvt/firmware.c
+++ b/drivers/gpu/drm/i915/gvt/firmware.c
@@ -50,21 +50,7 @@ struct gvt_firmware_header {

#define dev_to_drm_minor(d) dev_get_drvdata((d))

-static ssize_t
-gvt_firmware_read(struct file *filp, struct kobject *kobj,
- struct bin_attribute *attr, char *buf,
- loff_t offset, size_t count)
-{
- memcpy(buf, attr->private + offset, count);
- return count;
-}
-
-static struct bin_attribute firmware_attr = {
- .attr = {.name = "gvt_firmware", .mode = (S_IRUSR)},
- .read = gvt_firmware_read,
- .write = NULL,
- .mmap = NULL,
-};
+static BIN_ATTR_SIMPLE_ADMIN_RO(gvt_firmware);

static int expose_firmware_sysfs(struct intel_gvt *gvt)
{
@@ -107,10 +93,10 @@ static int expose_firmware_sysfs(struct intel_gvt *gvt)
crc32_start = offsetof(struct gvt_firmware_header, version);
h->crc32 = crc32_le(0, firmware + crc32_start, size - crc32_start);

- firmware_attr.size = size;
- firmware_attr.private = firmware;
+ bin_attr_gvt_firmware.size = size;
+ bin_attr_gvt_firmware.private = firmware;

- ret = device_create_bin_file(&pdev->dev, &firmware_attr);
+ ret = device_create_bin_file(&pdev->dev, &bin_attr_gvt_firmware);
if (ret) {
vfree(firmware);
return ret;
@@ -122,8 +108,8 @@ static void clean_firmware_sysfs(struct intel_gvt *gvt)
{
struct pci_dev *pdev = to_pci_dev(gvt->gt->i915->drm.dev);

- device_remove_bin_file(&pdev->dev, &firmware_attr);
- vfree(firmware_attr.private);
+ device_remove_bin_file(&pdev->dev, &bin_attr_gvt_firmware);
+ vfree(bin_attr_gvt_firmware.private);
}

/**
diff --git a/drivers/thermal/intel/int340x_thermal/int3400_thermal.c b/drivers/thermal/intel/int340x_thermal/int3400_thermal.c
index 427d370..6d4b51a 100644
--- a/drivers/thermal/intel/int340x_thermal/int3400_thermal.c
+++ b/drivers/thermal/intel/int340x_thermal/int3400_thermal.c
@@ -73,14 +73,7 @@ struct odvp_attr {
struct device_attribute attr;
};

-static ssize_t data_vault_read(struct file *file, struct kobject *kobj,
- struct bin_attribute *attr, char *buf, loff_t off, size_t count)
-{
- memcpy(buf, attr->private + off, count);
- return count;
-}
-
-static BIN_ATTR_RO(data_vault, 0);
+static BIN_ATTR_SIMPLE_RO(data_vault);

static struct bin_attribute *data_attributes[] = {
&bin_attr_data_vault,
diff --git a/init/initramfs.c b/init/initramfs.c
index da79760..5193fae 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -575,15 +575,7 @@ static int __init initramfs_async_setup(char *str)
#include <linux/initrd.h>
#include <linux/kexec.h>

-static ssize_t raw_read(struct file *file, struct kobject *kobj,
- struct bin_attribute *attr, char *buf,
- loff_t pos, size_t count)
-{
- memcpy(buf, attr->private + pos, count);
- return count;
-}
-
-static BIN_ATTR(initrd, 0440, raw_read, NULL, 0);
+static BIN_ATTR(initrd, 0440, sysfs_bin_attr_simple_read, NULL, 0);

void __init reserve_initrd_mem(void)
{
diff --git a/kernel/module/sysfs.c b/kernel/module/sysfs.c
index d964167..26efe13 100644
--- a/kernel/module/sysfs.c
+++ b/kernel/module/sysfs.c
@@ -146,17 +146,6 @@ struct module_notes_attrs {
struct bin_attribute attrs[] __counted_by(notes);
};

-static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
- struct bin_attribute *bin_attr,
- char *buf, loff_t pos, size_t count)
-{
- /*
- * The caller checked the pos and count against our size.
- */
- memcpy(buf, bin_attr->private + pos, count);
- return count;
-}
-
static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
unsigned int i)
{
@@ -205,7 +194,7 @@ static void add_notes_attrs(struct module *mod, const struct load_info *info)
nattr->attr.mode = 0444;
nattr->size = info->sechdrs[i].sh_size;
nattr->private = (void *)info->sechdrs[i].sh_addr;
- nattr->read = module_notes_read;
+ nattr->read = sysfs_bin_attr_simple_read;
++nattr;
}
++loaded;
--
2.43.0