PCI/sysfs: Convert "rom" to static attribute

The "rom" sysfs attribute allows access to the PCI Option ROM.  Previously
it was dynamically created either by pci_bus_add_device() or the
pci_sysfs_init() initcall, but since it doesn't need to be created or
removed dynamically, we can use a static attribute so the device model
takes care of addition and removal automatically.

Convert "rom" to a static attribute and use the .is_bin_visible() callback
to set the correct object size based on the ROM size.

Remove "rom_attr" from the struct pci_dev since it is no longer needed.

This attribute was added in the pre-git era by https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/drivers/pci/pci-sysfs.c?id=f6d553444da2

[bhelgaas: commit log]
Suggested-by: Oliver O'Halloran <oohall@gmail.com>
Link: https://lore.kernel.org/r/20210416205856.3234481-3-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index dc14daf..fa83736 100644 (file)
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1306,6 +1306,33 @@ static ssize_t pci_read_rom(struct file *filp, struct kobject *kobj,
 
        return count;
 }
+static BIN_ATTR(rom, 0600, pci_read_rom, pci_write_rom, 0);
+
+static struct bin_attribute *pci_dev_rom_attrs[] = {
+       &bin_attr_rom,
+       NULL,
+};
+
+static umode_t pci_dev_rom_attr_is_visible(struct kobject *kobj,
+                                          struct bin_attribute *a, int n)
+{
+       struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
+       size_t rom_size;
+
+       /* If the device has a ROM, try to expose it in sysfs. */
+       rom_size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
+       if (!rom_size)
+               return 0;
+
+       a->size = rom_size;
+
+       return a->attr.mode;
+}
+
+static const struct attribute_group pci_dev_rom_attr_group = {
+       .bin_attrs = pci_dev_rom_attrs,
+       .is_bin_visible = pci_dev_rom_attr_is_visible,
+};
 
 static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
                           const char *buf, size_t count)
@@ -1352,8 +1379,6 @@ error:
 int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
 {
        int retval;
-       int rom_size;
-       struct bin_attribute *attr;
 
        if (!sysfs_initialized)
                return -EACCES;
@@ -1362,43 +1387,15 @@ int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
        if (retval)
                goto err;
 
-       /* If the device has a ROM, try to expose it in sysfs. */
-       rom_size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
-       if (rom_size) {
-               attr = kzalloc(sizeof(*attr), GFP_ATOMIC);
-               if (!attr) {
-                       retval = -ENOMEM;
-                       goto err_resource_files;
-               }
-               sysfs_bin_attr_init(attr);
-               attr->size = rom_size;
-               attr->attr.name = "rom";
-               attr->attr.mode = 0600;
-               attr->read = pci_read_rom;
-               attr->write = pci_write_rom;
-               retval = sysfs_create_bin_file(&pdev->dev.kobj, attr);
-               if (retval) {
-                       kfree(attr);
-                       goto err_resource_files;
-               }
-               pdev->rom_attr = attr;
-       }
-
        /* add sysfs entries for various capabilities */
        retval = pci_create_capabilities_sysfs(pdev);
        if (retval)
-               goto err_rom_file;
+               goto err_resource_files;
 
        pci_create_firmware_label_files(pdev);
 
        return 0;
 
-err_rom_file:
-       if (pdev->rom_attr) {
-               sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
-               kfree(pdev->rom_attr);
-               pdev->rom_attr = NULL;
-       }
 err_resource_files:
        pci_remove_resource_files(pdev);
 err:
@@ -1427,13 +1424,6 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
 
        pci_remove_capabilities_sysfs(pdev);
        pci_remove_resource_files(pdev);
-
-       if (pdev->rom_attr) {
-               sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
-               kfree(pdev->rom_attr);
-               pdev->rom_attr = NULL;
-       }
-
        pci_remove_firmware_label_files(pdev);
 }
 
@@ -1526,6 +1516,7 @@ static const struct attribute_group pci_dev_group = {
 const struct attribute_group *pci_dev_groups[] = {
        &pci_dev_group,
        &pci_dev_config_attr_group,
+       &pci_dev_rom_attr_group,
        NULL,
 };
 

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 86c799c..45f1fef 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -458,7 +458,6 @@ struct pci_dev {
 
        u32             saved_config_space[16]; /* Config space saved at suspend time */
        struct hlist_head saved_cap_space;
-       struct bin_attribute *rom_attr;         /* Attribute descriptor for sysfs ROM entry */
        int             rom_attr_enabled;       /* Display of ROM attribute enabled? */
        struct bin_attribute *res_attr[DEVICE_COUNT_RESOURCE]; /* sysfs file for resources */
        struct bin_attribute *res_attr_wc[DEVICE_COUNT_RESOURCE]; /* sysfs file for WC mapping of resources */