From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org
Cc: "Krzysztof Wilczyński" <kw@linux.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Sasha Levin" <sashal@kernel.org>
Subject: [PATCH 5.10.y 2/3] PCI/sysfs: Use sysfs_emit() and sysfs_emit_at() in "show" functions
Date: Mon, 20 Oct 2025 12:25:17 -0400 [thread overview]
Message-ID: <20251020162518.1838256-2-sashal@kernel.org> (raw)
In-Reply-To: <20251020162518.1838256-1-sashal@kernel.org>
From: Krzysztof Wilczyński <kw@linux.com>
[ Upstream commit ad025f8e46f3dbf09b1bf8d7a5b4ce858df74544 ]
The sysfs_emit() and sysfs_emit_at() functions were introduced to make it
less ambiguous which function is preferred when writing to the output
buffer in a device attribute's "show" callback [1].
Convert the PCI sysfs object "show" functions from sprintf(), snprintf()
and scnprintf() to sysfs_emit() and sysfs_emit_at() accordingly, as the
latter is aware of the PAGE_SIZE buffer and correctly returns the number of
bytes written into the buffer.
No functional change intended.
[1] Documentation/filesystems/sysfs.rst
[bhelgaas: drop dsm_label_utf16s_to_utf8s(), link speed/width changes]
Link: https://lore.kernel.org/r/20210416205856.3234481-10-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Stable-dep-of: 48991e493507 ("PCI/sysfs: Ensure devices are powered for config reads")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/pci-label.c | 10 +++---
drivers/pci/pci-sysfs.c | 72 ++++++++++++++++++++---------------------
2 files changed, 40 insertions(+), 42 deletions(-)
diff --git a/drivers/pci/pci-label.c b/drivers/pci/pci-label.c
index cd84cf52a92e1..6c406453b49f4 100644
--- a/drivers/pci/pci-label.c
+++ b/drivers/pci/pci-label.c
@@ -62,13 +62,11 @@ static size_t find_smbios_instance_string(struct pci_dev *pdev, char *buf,
donboard->devfn == devfn) {
if (buf) {
if (attribute == SMBIOS_ATTR_INSTANCE_SHOW)
- return scnprintf(buf, PAGE_SIZE,
- "%d\n",
- donboard->instance);
+ return sysfs_emit(buf, "%d\n",
+ donboard->instance);
else if (attribute == SMBIOS_ATTR_LABEL_SHOW)
- return scnprintf(buf, PAGE_SIZE,
- "%s\n",
- dmi->name);
+ return sysfs_emit(buf, "%s\n",
+ dmi->name);
}
return strlen(dmi->name);
}
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 5a9d942198586..3fddd421bbe66 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -39,7 +39,7 @@ field##_show(struct device *dev, struct device_attribute *attr, char *buf) \
struct pci_dev *pdev; \
\
pdev = to_pci_dev(dev); \
- return sprintf(buf, format_string, pdev->field); \
+ return sysfs_emit(buf, format_string, pdev->field); \
} \
static DEVICE_ATTR_RO(field)
@@ -56,7 +56,7 @@ static ssize_t broken_parity_status_show(struct device *dev,
char *buf)
{
struct pci_dev *pdev = to_pci_dev(dev);
- return sprintf(buf, "%u\n", pdev->broken_parity_status);
+ return sysfs_emit(buf, "%u\n", pdev->broken_parity_status);
}
static ssize_t broken_parity_status_store(struct device *dev,
@@ -129,7 +129,7 @@ static ssize_t power_state_show(struct device *dev,
{
struct pci_dev *pdev = to_pci_dev(dev);
- return sprintf(buf, "%s\n", pci_power_name(pdev->current_state));
+ return sysfs_emit(buf, "%s\n", pci_power_name(pdev->current_state));
}
static DEVICE_ATTR_RO(power_state);
@@ -138,10 +138,10 @@ static ssize_t resource_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct pci_dev *pci_dev = to_pci_dev(dev);
- char *str = buf;
int i;
int max;
resource_size_t start, end;
+ size_t len = 0;
if (pci_dev->subordinate)
max = DEVICE_COUNT_RESOURCE;
@@ -151,12 +151,12 @@ static ssize_t resource_show(struct device *dev, struct device_attribute *attr,
for (i = 0; i < max; i++) {
struct resource *res = &pci_dev->resource[i];
pci_resource_to_user(pci_dev, i, res, &start, &end);
- str += sprintf(str, "0x%016llx 0x%016llx 0x%016llx\n",
- (unsigned long long)start,
- (unsigned long long)end,
- (unsigned long long)res->flags);
+ len += sysfs_emit_at(buf, len, "0x%016llx 0x%016llx 0x%016llx\n",
+ (unsigned long long)start,
+ (unsigned long long)end,
+ (unsigned long long)res->flags);
}
- return (str - buf);
+ return len;
}
static DEVICE_ATTR_RO(resource);
@@ -165,8 +165,8 @@ static ssize_t max_link_speed_show(struct device *dev,
{
struct pci_dev *pdev = to_pci_dev(dev);
- return sprintf(buf, "%s\n",
- pci_speed_string(pcie_get_speed_cap(pdev)));
+ return sysfs_emit(buf, "%s\n",
+ pci_speed_string(pcie_get_speed_cap(pdev)));
}
static DEVICE_ATTR_RO(max_link_speed);
@@ -175,7 +175,7 @@ static ssize_t max_link_width_show(struct device *dev,
{
struct pci_dev *pdev = to_pci_dev(dev);
- return sprintf(buf, "%u\n", pcie_get_width_cap(pdev));
+ return sysfs_emit(buf, "%u\n", pcie_get_width_cap(pdev));
}
static DEVICE_ATTR_RO(max_link_width);
@@ -193,7 +193,7 @@ static ssize_t current_link_speed_show(struct device *dev,
speed = pcie_link_speed[linkstat & PCI_EXP_LNKSTA_CLS];
- return sprintf(buf, "%s\n", pci_speed_string(speed));
+ return sysfs_emit(buf, "%s\n", pci_speed_string(speed));
}
static DEVICE_ATTR_RO(current_link_speed);
@@ -208,7 +208,7 @@ static ssize_t current_link_width_show(struct device *dev,
if (err)
return -EINVAL;
- return sprintf(buf, "%u\n",
+ return sysfs_emit(buf, "%u\n",
(linkstat & PCI_EXP_LNKSTA_NLW) >> PCI_EXP_LNKSTA_NLW_SHIFT);
}
static DEVICE_ATTR_RO(current_link_width);
@@ -225,7 +225,7 @@ static ssize_t secondary_bus_number_show(struct device *dev,
if (err)
return -EINVAL;
- return sprintf(buf, "%u\n", sec_bus);
+ return sysfs_emit(buf, "%u\n", sec_bus);
}
static DEVICE_ATTR_RO(secondary_bus_number);
@@ -241,7 +241,7 @@ static ssize_t subordinate_bus_number_show(struct device *dev,
if (err)
return -EINVAL;
- return sprintf(buf, "%u\n", sub_bus);
+ return sysfs_emit(buf, "%u\n", sub_bus);
}
static DEVICE_ATTR_RO(subordinate_bus_number);
@@ -251,7 +251,7 @@ static ssize_t ari_enabled_show(struct device *dev,
{
struct pci_dev *pci_dev = to_pci_dev(dev);
- return sprintf(buf, "%u\n", pci_ari_enabled(pci_dev->bus));
+ return sysfs_emit(buf, "%u\n", pci_ari_enabled(pci_dev->bus));
}
static DEVICE_ATTR_RO(ari_enabled);
@@ -260,11 +260,11 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
{
struct pci_dev *pci_dev = to_pci_dev(dev);
- return sprintf(buf, "pci:v%08Xd%08Xsv%08Xsd%08Xbc%02Xsc%02Xi%02X\n",
- pci_dev->vendor, pci_dev->device,
- pci_dev->subsystem_vendor, pci_dev->subsystem_device,
- (u8)(pci_dev->class >> 16), (u8)(pci_dev->class >> 8),
- (u8)(pci_dev->class));
+ return sysfs_emit(buf, "pci:v%08Xd%08Xsv%08Xsd%08Xbc%02Xsc%02Xi%02X\n",
+ pci_dev->vendor, pci_dev->device,
+ pci_dev->subsystem_vendor, pci_dev->subsystem_device,
+ (u8)(pci_dev->class >> 16), (u8)(pci_dev->class >> 8),
+ (u8)(pci_dev->class));
}
static DEVICE_ATTR_RO(modalias);
@@ -302,7 +302,7 @@ static ssize_t enable_show(struct device *dev, struct device_attribute *attr,
struct pci_dev *pdev;
pdev = to_pci_dev(dev);
- return sprintf(buf, "%u\n", atomic_read(&pdev->enable_cnt));
+ return sysfs_emit(buf, "%u\n", atomic_read(&pdev->enable_cnt));
}
static DEVICE_ATTR_RW(enable);
@@ -338,7 +338,7 @@ static ssize_t numa_node_store(struct device *dev,
static ssize_t numa_node_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
- return sprintf(buf, "%d\n", dev->numa_node);
+ return sysfs_emit(buf, "%d\n", dev->numa_node);
}
static DEVICE_ATTR_RW(numa_node);
#endif
@@ -348,7 +348,7 @@ static ssize_t dma_mask_bits_show(struct device *dev,
{
struct pci_dev *pdev = to_pci_dev(dev);
- return sprintf(buf, "%d\n", fls64(pdev->dma_mask));
+ return sysfs_emit(buf, "%d\n", fls64(pdev->dma_mask));
}
static DEVICE_ATTR_RO(dma_mask_bits);
@@ -356,7 +356,7 @@ static ssize_t consistent_dma_mask_bits_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
- return sprintf(buf, "%d\n", fls64(dev->coherent_dma_mask));
+ return sysfs_emit(buf, "%d\n", fls64(dev->coherent_dma_mask));
}
static DEVICE_ATTR_RO(consistent_dma_mask_bits);
@@ -366,9 +366,9 @@ static ssize_t msi_bus_show(struct device *dev, struct device_attribute *attr,
struct pci_dev *pdev = to_pci_dev(dev);
struct pci_bus *subordinate = pdev->subordinate;
- return sprintf(buf, "%u\n", subordinate ?
- !(subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI)
- : !pdev->no_msi);
+ return sysfs_emit(buf, "%u\n", subordinate ?
+ !(subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI)
+ : !pdev->no_msi);
}
static ssize_t msi_bus_store(struct device *dev, struct device_attribute *attr,
@@ -545,7 +545,7 @@ static ssize_t d3cold_allowed_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct pci_dev *pdev = to_pci_dev(dev);
- return sprintf(buf, "%u\n", pdev->d3cold_allowed);
+ return sysfs_emit(buf, "%u\n", pdev->d3cold_allowed);
}
static DEVICE_ATTR_RW(d3cold_allowed);
#endif
@@ -559,7 +559,7 @@ static ssize_t devspec_show(struct device *dev,
if (np == NULL)
return 0;
- return sprintf(buf, "%pOF", np);
+ return sysfs_emit(buf, "%pOF", np);
}
static DEVICE_ATTR_RO(devspec);
#endif
@@ -605,7 +605,7 @@ static ssize_t driver_override_show(struct device *dev,
ssize_t len;
device_lock(dev);
- len = scnprintf(buf, PAGE_SIZE, "%s\n", pdev->driver_override);
+ len = sysfs_emit(buf, "%s\n", pdev->driver_override);
device_unlock(dev);
return len;
}
@@ -681,11 +681,11 @@ static ssize_t boot_vga_show(struct device *dev, struct device_attribute *attr,
struct pci_dev *vga_dev = vga_default_device();
if (vga_dev)
- return sprintf(buf, "%u\n", (pdev == vga_dev));
+ return sysfs_emit(buf, "%u\n", (pdev == vga_dev));
- return sprintf(buf, "%u\n",
- !!(pdev->resource[PCI_ROM_RESOURCE].flags &
- IORESOURCE_ROM_SHADOW));
+ return sysfs_emit(buf, "%u\n",
+ !!(pdev->resource[PCI_ROM_RESOURCE].flags &
+ IORESOURCE_ROM_SHADOW));
}
static DEVICE_ATTR_RO(boot_vga);
--
2.51.0
next prev parent reply other threads:[~2025-10-20 16:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-16 12:57 FAILED: patch "[PATCH] PCI/sysfs: Ensure devices are powered for config reads" failed to apply to 5.10-stable tree gregkh
2025-10-20 16:25 ` [PATCH 5.10.y 1/3] PCI: Add sysfs attribute for device power state Sasha Levin
2025-10-20 16:25 ` Sasha Levin [this message]
2025-10-20 16:25 ` [PATCH 5.10.y 3/3] PCI/sysfs: Ensure devices are powered for config reads Sasha Levin
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