From 93bb8e352a9136a56dd26762bf54cf6554cfa96c Mon Sep 17 00:00:00 2001 From: =?utf8?q?Krzysztof=20Wilczy=C5=84ski?= Date: Thu, 29 Jul 2021 23:32:34 +0000 Subject: [PATCH] sysfs: Invoke iomem_get_mapping() from the sysfs open callback MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Defer invocation of the iomem_get_mapping() to the sysfs open callback so that it can be executed as needed when the binary sysfs object has been accessed. To do that, convert the "mapping" member of the struct bin_attribute from a pointer to the struct address_space into a function pointer with a signature that requires the same return type, and then updates the sysfs_kf_bin_open() to invoke provided function should the function pointer be valid. Also, convert every invocation of iomem_get_mapping() into a function pointer assignment, therefore allowing for the iomem_get_mapping() invocation to be deferred to when the sysfs open callback runs. Thus, this change removes the need for the fs_initcalls to complete before any other sub-system that uses the iomem_get_mapping() would be able to invoke it safely without leading to a failure and an Oops related to an invalid iomem_get_mapping() access. Suggested-by: Dan Williams Reviewed-by: Dan Williams Acked-by: Bjorn Helgaas Signed-off-by: Dan Williams Signed-off-by: Krzysztof Wilczyński Link: https://lore.kernel.org/r/20210729233235.1508920-2-kw@linux.com Signed-off-by: Greg Kroah-Hartman --- drivers/pci/pci-sysfs.c | 6 +++--- fs/sysfs/file.c | 2 +- include/linux/sysfs.h | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 5d63df7..76e5545 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -965,7 +965,7 @@ void pci_create_legacy_files(struct pci_bus *b) b->legacy_io->read = pci_read_legacy_io; b->legacy_io->write = pci_write_legacy_io; b->legacy_io->mmap = pci_mmap_legacy_io; - b->legacy_io->mapping = iomem_get_mapping(); + b->legacy_io->mapping = iomem_get_mapping; pci_adjust_legacy_attr(b, pci_mmap_io); error = device_create_bin_file(&b->dev, b->legacy_io); if (error) @@ -978,7 +978,7 @@ void pci_create_legacy_files(struct pci_bus *b) b->legacy_mem->size = 1024*1024; b->legacy_mem->attr.mode = 0600; b->legacy_mem->mmap = pci_mmap_legacy_mem; - b->legacy_io->mapping = iomem_get_mapping(); + b->legacy_io->mapping = iomem_get_mapping; pci_adjust_legacy_attr(b, pci_mmap_mem); error = device_create_bin_file(&b->dev, b->legacy_mem); if (error) @@ -1195,7 +1195,7 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine) } } if (res_attr->mmap) - res_attr->mapping = iomem_get_mapping(); + res_attr->mapping = iomem_get_mapping; res_attr->attr.name = res_attr_name; res_attr->attr.mode = 0600; res_attr->size = pci_resource_len(pdev, num); diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 9aefa77..a3ee4c3 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -175,7 +175,7 @@ static int sysfs_kf_bin_open(struct kernfs_open_file *of) struct bin_attribute *battr = of->kn->priv; if (battr->mapping) - of->file->f_mapping = battr->mapping; + of->file->f_mapping = battr->mapping(); return 0; } diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index a12556a..d5bcc89 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -176,7 +176,7 @@ struct bin_attribute { struct attribute attr; size_t size; void *private; - struct address_space *mapping; + struct address_space *(*mapping)(void); ssize_t (*read)(struct file *, struct kobject *, struct bin_attribute *, char *, loff_t, size_t); ssize_t (*write)(struct file *, struct kobject *, struct bin_attribute *, -- 2.7.4