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sysfs: copy bin mmap support from fs/sysfs/bin.c to fs/sysfs/file.c

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sysfs bin file handling will be merged into the regular file support.
This patch copies mmap support from bin so that fs/sysfs/file.c can
handle mmapping bin files.

The code is copied mostly verbatim with the following updates.

* ->mmapped and ->vm_ops are added to sysfs_open_file and bin_buffer
  references are replaced with sysfs_open_file ones.

* Symbols are prefixed with sysfs_.

* sysfs_unmap_bin_file() grabs sysfs_open_dirent and traverses
  ->files.  Invocation of this function is added to
  sysfs_addrm_finish().

* sysfs_bin_mmap() is added to sysfs_bin_operations.

This is a preparation and the new mmap path isn't used yet.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tejun Heo 2013-10-01 17:42:07 -04:00 committed by Greg Kroah-Hartman
parent 2f0c6b7593
commit 73d9714627
3 changed files with 249 additions and 1 deletions
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1
fs/sysfs/dir.c
View file

@ -595,6 +595,7 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
acxt->removed = sd->u.removed_list;
sysfs_deactivate(sd);
sysfs_unmap_bin_file(sd);
unmap_bin_file(sd);
sysfs_put(sd);
}

247
fs/sysfs/file.c
View file

@ -22,6 +22,7 @@
#include <linux/limits.h>
#include <linux/uaccess.h>
#include <linux/seq_file.h>
#include <linux/mm.h>
#include "sysfs.h"
@ -52,6 +53,9 @@ struct sysfs_open_file {
struct mutex mutex;
int event;
struct list_head list;
bool mmapped;
const struct vm_operations_struct *vm_ops;
};
static bool sysfs_is_bin(struct sysfs_dirent *sd)
@ -301,6 +305,218 @@ out_free:
return len;
}
static void sysfs_bin_vma_open(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct sysfs_open_file *of = sysfs_of(file);
if (!of->vm_ops)
return;
if (!sysfs_get_active(of->sd))
return;
if (of->vm_ops->open)
of->vm_ops->open(vma);
sysfs_put_active(of->sd);
}
static int sysfs_bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct file *file = vma->vm_file;
struct sysfs_open_file *of = sysfs_of(file);
int ret;
if (!of->vm_ops)
return VM_FAULT_SIGBUS;
if (!sysfs_get_active(of->sd))
return VM_FAULT_SIGBUS;
ret = VM_FAULT_SIGBUS;
if (of->vm_ops->fault)
ret = of->vm_ops->fault(vma, vmf);
sysfs_put_active(of->sd);
return ret;
}
static int sysfs_bin_page_mkwrite(struct vm_area_struct *vma,
struct vm_fault *vmf)
{
struct file *file = vma->vm_file;
struct sysfs_open_file *of = sysfs_of(file);
int ret;
if (!of->vm_ops)
return VM_FAULT_SIGBUS;
if (!sysfs_get_active(of->sd))
return VM_FAULT_SIGBUS;
ret = 0;
if (of->vm_ops->page_mkwrite)
ret = of->vm_ops->page_mkwrite(vma, vmf);
else
file_update_time(file);
sysfs_put_active(of->sd);
return ret;
}
static int sysfs_bin_access(struct vm_area_struct *vma, unsigned long addr,
void *buf, int len, int write)
{
struct file *file = vma->vm_file;
struct sysfs_open_file *of = sysfs_of(file);
int ret;
if (!of->vm_ops)
return -EINVAL;
if (!sysfs_get_active(of->sd))
return -EINVAL;
ret = -EINVAL;
if (of->vm_ops->access)
ret = of->vm_ops->access(vma, addr, buf, len, write);
sysfs_put_active(of->sd);
return ret;
}
#ifdef CONFIG_NUMA
static int sysfs_bin_set_policy(struct vm_area_struct *vma,
struct mempolicy *new)
{
struct file *file = vma->vm_file;
struct sysfs_open_file *of = sysfs_of(file);
int ret;
if (!of->vm_ops)
return 0;
if (!sysfs_get_active(of->sd))
return -EINVAL;
ret = 0;
if (of->vm_ops->set_policy)
ret = of->vm_ops->set_policy(vma, new);
sysfs_put_active(of->sd);
return ret;
}
static struct mempolicy *sysfs_bin_get_policy(struct vm_area_struct *vma,
unsigned long addr)
{
struct file *file = vma->vm_file;
struct sysfs_open_file *of = sysfs_of(file);
struct mempolicy *pol;
if (!of->vm_ops)
return vma->vm_policy;
if (!sysfs_get_active(of->sd))
return vma->vm_policy;
pol = vma->vm_policy;
if (of->vm_ops->get_policy)
pol = of->vm_ops->get_policy(vma, addr);
sysfs_put_active(of->sd);
return pol;
}
static int sysfs_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 sysfs_open_file *of = sysfs_of(file);
int ret;
if (!of->vm_ops)
return 0;
if (!sysfs_get_active(of->sd))
return 0;
ret = 0;
if (of->vm_ops->migrate)
ret = of->vm_ops->migrate(vma, from, to, flags);
sysfs_put_active(of->sd);
return ret;
}
#endif
static const struct vm_operations_struct sysfs_bin_vm_ops = {
.open = sysfs_bin_vma_open,
.fault = sysfs_bin_fault,
.page_mkwrite = sysfs_bin_page_mkwrite,
.access = sysfs_bin_access,
#ifdef CONFIG_NUMA
.set_policy = sysfs_bin_set_policy,
.get_policy = sysfs_bin_get_policy,
.migrate = sysfs_bin_migrate,
#endif
};
static int sysfs_bin_mmap(struct file *file, struct vm_area_struct *vma)
{
struct sysfs_open_file *of = sysfs_of(file);
struct bin_attribute *battr = of->sd->s_bin_attr.bin_attr;
struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
int rc;
mutex_lock(&of->mutex);
/* need of->sd for battr, its parent for kobj */
rc = -ENODEV;
if (!sysfs_get_active(of->sd))
goto out_unlock;
rc = -EINVAL;
if (!battr->mmap)
goto out_put;
rc = battr->mmap(file, kobj, battr, 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 (of->mmapped && of->vm_ops != vma->vm_ops)
goto out_put;
/*
* It is not possible to successfully wrap close.
* So error if someone is trying to use close.
*/
rc = -EINVAL;
if (vma->vm_ops && vma->vm_ops->close)
goto out_put;
rc = 0;
of->mmapped = 1;
of->vm_ops = vma->vm_ops;
vma->vm_ops = &sysfs_bin_vm_ops;
out_put:
sysfs_put_active(of->sd);
out_unlock:
mutex_unlock(&of->mutex);
return rc;
}
/**
* sysfs_get_open_dirent - get or create sysfs_open_dirent
* @sd: target sysfs_dirent
@ -375,7 +591,9 @@ static void sysfs_put_open_dirent(struct sysfs_dirent *sd,
mutex_lock(&sysfs_open_file_mutex);
spin_lock_irqsave(&sysfs_open_dirent_lock, flags);
list_del(&of->list);
if (of)
list_del(&of->list);
if (atomic_dec_and_test(&od->refcnt))
sd->s_attr.open = NULL;
else
@ -477,6 +695,32 @@ static int sysfs_release(struct inode *inode, struct file *filp)
return 0;
}
void sysfs_unmap_bin_file(struct sysfs_dirent *sd)
{
struct sysfs_open_dirent *od;
struct sysfs_open_file *of;
if (!sysfs_is_bin(sd))
return;
spin_lock_irq(&sysfs_open_dirent_lock);
od = sd->s_attr.open;
if (od)
atomic_inc(&od->refcnt);
spin_unlock_irq(&sysfs_open_dirent_lock);
if (!od)
return;
mutex_lock(&sysfs_open_file_mutex);
list_for_each_entry(of, &od->files, list) {
struct inode *inode = file_inode(of->file);
unmap_mapping_range(inode->i_mapping, 0, 0, 1);
}
mutex_unlock(&sysfs_open_file_mutex);
sysfs_put_open_dirent(sd, NULL);
}
/* Sysfs attribute files are pollable. The idea is that you read
* the content and then you use 'poll' or 'select' to wait for
* the content to change. When the content changes (assuming the
@ -562,6 +806,7 @@ const struct file_operations sysfs_bin_operations = {
.read = sysfs_bin_read,
.write = sysfs_write_file,
.llseek = generic_file_llseek,
.mmap = sysfs_bin_mmap,
};
int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,

2
fs/sysfs/sysfs.h
View file

@ -220,6 +220,8 @@ int sysfs_add_file(struct sysfs_dirent *dir_sd,
int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
const struct attribute *attr, int type,
umode_t amode, const void *ns);
void sysfs_unmap_bin_file(struct sysfs_dirent *sd);
/*
* bin.c
*/