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Subject[RFC][PATCH 3/9] sysfs: Use remap_file_mappings.

Instead of wrapping all of the sysfs binary file vm operations
when the backing kobject goes away, we can more easily change
vm_ops on the vma when the backing kobject goes away.

Leading to simpler and more easily maintained code.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
fs/sysfs/bin.c | 193 +-------------------------------------------------------
1 files changed, 2 insertions(+), 191 deletions(-)

diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
index 93e0c02..898163c 100644
--- a/fs/sysfs/bin.c
+++ b/fs/sysfs/bin.c
@@ -39,8 +39,6 @@ static DEFINE_MUTEX(sysfs_bin_lock);
struct bin_buffer {
struct mutex mutex;
void *buffer;
- int mmapped;
- struct vm_operations_struct *vm_ops;
struct file *file;
struct hlist_node list;
};
@@ -181,175 +179,6 @@ out_free:
return count;
}

-static void bin_vma_open(struct vm_area_struct *vma)
-{
- struct file *file = vma->vm_file;
- struct bin_buffer *bb = file->private_data;
- struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
-
- if (!bb->vm_ops || !bb->vm_ops->open)
- return;
-
- if (!sysfs_get_active_two(attr_sd))
- return;
-
- bb->vm_ops->open(vma);
-
- sysfs_put_active_two(attr_sd);
-}
-
-static void bin_vma_close(struct vm_area_struct *vma)
-{
- struct file *file = vma->vm_file;
- struct bin_buffer *bb = file->private_data;
- struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
-
- if (!bb->vm_ops || !bb->vm_ops->close)
- return;
-
- if (!sysfs_get_active_two(attr_sd))
- return;
-
- bb->vm_ops->close(vma);
-
- sysfs_put_active_two(attr_sd);
-}
-
-static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
- struct file *file = vma->vm_file;
- struct bin_buffer *bb = file->private_data;
- struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
- int ret;
-
- if (!bb->vm_ops || !bb->vm_ops->fault)
- return VM_FAULT_SIGBUS;
-
- if (!sysfs_get_active_two(attr_sd))
- return VM_FAULT_SIGBUS;
-
- ret = bb->vm_ops->fault(vma, vmf);
-
- sysfs_put_active_two(attr_sd);
- return ret;
-}
-
-static int bin_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
- struct file *file = vma->vm_file;
- struct bin_buffer *bb = file->private_data;
- struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
- int ret;
-
- if (!bb->vm_ops)
- return VM_FAULT_SIGBUS;
-
- if (!bb->vm_ops->page_mkwrite)
- return 0;
-
- if (!sysfs_get_active_two(attr_sd))
- return VM_FAULT_SIGBUS;
-
- ret = bb->vm_ops->page_mkwrite(vma, vmf);
-
- sysfs_put_active_two(attr_sd);
- return ret;
-}
-
-static int bin_access(struct vm_area_struct *vma, unsigned long addr,
- void *buf, int len, int write)
-{
- struct file *file = vma->vm_file;
- struct bin_buffer *bb = file->private_data;
- struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
- int ret;
-
- if (!bb->vm_ops || !bb->vm_ops->access)
- return -EINVAL;
-
- if (!sysfs_get_active_two(attr_sd))
- return -EINVAL;
-
- ret = bb->vm_ops->access(vma, addr, buf, len, write);
-
- sysfs_put_active_two(attr_sd);
- return ret;
-}
-
-#ifdef CONFIG_NUMA
-static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
-{
- struct file *file = vma->vm_file;
- struct bin_buffer *bb = file->private_data;
- struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
- int ret;
-
- if (!bb->vm_ops || !bb->vm_ops->set_policy)
- return 0;
-
- if (!sysfs_get_active_two(attr_sd))
- return -EINVAL;
-
- ret = bb->vm_ops->set_policy(vma, new);
-
- sysfs_put_active_two(attr_sd);
- return ret;
-}
-
-static struct mempolicy *bin_get_policy(struct vm_area_struct *vma,
- unsigned long addr)
-{
- struct file *file = vma->vm_file;
- struct bin_buffer *bb = file->private_data;
- struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
- struct mempolicy *pol;
-
- if (!bb->vm_ops || !bb->vm_ops->get_policy)
- return vma->vm_policy;
-
- if (!sysfs_get_active_two(attr_sd))
- return vma->vm_policy;
-
- pol = bb->vm_ops->get_policy(vma, addr);
-
- sysfs_put_active_two(attr_sd);
- return pol;
-}
-
-static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
- const nodemask_t *to, unsigned long flags)
-{
- struct file *file = vma->vm_file;
- struct bin_buffer *bb = file->private_data;
- struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
- int ret;
-
- if (!bb->vm_ops || !bb->vm_ops->migrate)
- return 0;
-
- if (!sysfs_get_active_two(attr_sd))
- return 0;
-
- ret = bb->vm_ops->migrate(vma, from, to, flags);
-
- sysfs_put_active_two(attr_sd);
- return ret;
-}
-#endif
-
-static struct vm_operations_struct bin_vm_ops = {
- .open = bin_vma_open,
- .close = bin_vma_close,
- .fault = bin_fault,
- .page_mkwrite = bin_page_mkwrite,
- .access = bin_access,
-#ifdef CONFIG_NUMA
- .set_policy = bin_set_policy,
- .get_policy = bin_get_policy,
- .migrate = bin_migrate,
-#endif
-};
-
static int mmap(struct file *file, struct vm_area_struct *vma)
{
struct bin_buffer *bb = file->private_data;
@@ -370,25 +199,7 @@ static int mmap(struct file *file, struct vm_area_struct *vma)
goto out_put;

rc = attr->mmap(kobj, attr, vma);
- if (rc)
- goto out_put;
-
- /*
- * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
- * to satisfy versions of X which crash if the mmap fails: that
- * substitutes a new vm_file, and we don't then want bin_vm_ops.
- */
- if (vma->vm_file != file)
- goto out_put;
-
- rc = -EINVAL;
- if (bb->mmapped && bb->vm_ops != vma->vm_ops)
- goto out_put;

- rc = 0;
- bb->mmapped = 1;
- bb->vm_ops = vma->vm_ops;
- vma->vm_ops = &bin_vm_ops;
out_put:
sysfs_put_active_two(attr_sd);
out_unlock:
@@ -475,9 +286,9 @@ void unmap_bin_file(struct sysfs_dirent *attr_sd)
mutex_lock(&sysfs_bin_lock);

hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) {
- struct inode *inode = bb->file->f_path.dentry->d_inode;
+ struct file *file = bb->file;

- unmap_mapping_range(inode->i_mapping, 0, 0, 1);
+ remap_file_mappings(file, &revoked_vm_ops);
}

mutex_unlock(&sysfs_bin_lock);
--
1.6.1.2.350.g88cc


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