static void free_fdmem(void *ptr)
{
is_vmalloc_addr(ptr) ? vfree(ptr) : kfree(ptr);
}
void memunmap(void *addr)
{
if (is_vmalloc_addr(addr))
iounmap((void __iomem *) addr);
}
static int traverse(struct seq_file *m, loff_t offset)
{
loff_t pos = 0, index;
int error = 0;
void *p;
m->version = 0;
index = 0;
m->count = m->from = 0;
if (!offset) {
m->index = index;
return 0;
}
if (!m->buf) {
m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
if (!m->buf)
return -ENOMEM;
}
p = m->op->start(m, &index);
while (p) {
error = PTR_ERR(p);
if (IS_ERR(p))
break;
error = m->op->show(m, p);
if (error < 0)
break;
if (unlikely(error)) {
error = 0;
m->count = 0;
}
if (seq_overflow(m))
goto Eoverflow;
if (pos + m->count > offset) {
m->from = offset - pos;
m->count -= m->from;
m->index = index;
break;
}
pos += m->count;
m->count = 0;
if (pos == offset) {
index++;
m->index = index;
break;
}
p = m->op->next(m, p, &index);
}
m->op->stop(m, p);
m->index = index;
return error;
Eoverflow:
m->op->stop(m, p);
#ifdef CONFIG_LOW_ORDER_SEQ_MALLOC
is_vmalloc_addr(m->buf) ? vfree(m->buf) : kfree(m->buf);
m->count = 0;
m->size <<= 1;
if (m->size <= (2* PAGE_SIZE))
m->buf = kmalloc(m->size, GFP_KERNEL);
else
m->buf = vmalloc(m->size);
#else
kfree(m->buf);
m->count = 0;
m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
#endif
return !m->buf ? -ENOMEM : -EAGAIN;
}
/**
* seq_read - ->read() method for sequential files.
* @file: the file to read from
* @buf: the buffer to read to
* @size: the maximum number of bytes to read
* @ppos: the current position in the file
*
* Ready-made ->f_op->read()
*/
ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{
struct seq_file *m = file->private_data;
size_t copied = 0;
loff_t pos;
size_t n;
void *p;
int err = 0;
mutex_lock(&m->lock);
/*
* seq_file->op->..m_start/m_stop/m_next may do special actions
* or optimisations based on the file->f_version, so we want to
* pass the file->f_version to those methods.
*
* seq_file->version is just copy of f_version, and seq_file
* methods can treat it simply as file version.
* It is copied in first and copied out after all operations.
* It is convenient to have it as part of structure to avoid the
* need of passing another argument to all the seq_file methods.
*/
m->version = file->f_version;
/* Don't assume *ppos is where we left it */
if (unlikely(*ppos != m->read_pos)) {
while ((err = traverse(m, *ppos)) == -EAGAIN)
;
if (err) {
/* With prejudice... */
m->read_pos = 0;
m->version = 0;
m->index = 0;
m->count = 0;
goto Done;
} else {
m->read_pos = *ppos;
}
}
/* grab buffer if we didn't have one */
if (!m->buf) {
m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
if (!m->buf)
goto Enomem;
}
/* if not empty - flush it first */
if (m->count) {
n = min(m->count, size);
err = copy_to_user(buf, m->buf + m->from, n);
if (err)
goto Efault;
m->count -= n;
m->from += n;
size -= n;
buf += n;
copied += n;
if (!m->count)
m->index++;
if (!size)
goto Done;
}
/* we need at least one record in buffer */
pos = m->index;
p = m->op->start(m, &pos);
while (1) {
err = PTR_ERR(p);
if (!p || IS_ERR(p))
break;
err = m->op->show(m, p);
if (err < 0)
break;
if (unlikely(err))
m->count = 0;
if (unlikely(!m->count)) {
p = m->op->next(m, p, &pos);
m->index = pos;
continue;
}
if (m->count < m->size)
goto Fill;
m->op->stop(m, p);
#ifdef CONFIG_LOW_ORDER_SEQ_MALLOC
is_vmalloc_addr(m->buf) ? vfree(m->buf) : kfree(m->buf);
m->count = 0;
m->size <<= 1;
if (m->size <= (2* PAGE_SIZE))
m->buf = kmalloc(m->size, GFP_KERNEL);
else
m->buf = vmalloc(m->size);
#else
kfree(m->buf);
m->count = 0;
m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
#endif
if (!m->buf)
goto Enomem;
m->version = 0;
pos = m->index;
p = m->op->start(m, &pos);
}
m->op->stop(m, p);
m->count = 0;
goto Done;
Fill:
/* they want more? let's try to get some more */
while (m->count < size) {
size_t offs = m->count;
loff_t next = pos;
p = m->op->next(m, p, &next);
if (!p || IS_ERR(p)) {
err = PTR_ERR(p);
break;
}
err = m->op->show(m, p);
if (seq_overflow(m) || err) {
m->count = offs;
if (likely(err <= 0))
break;
}
pos = next;
}
m->op->stop(m, p);
n = min(m->count, size);
err = copy_to_user(buf, m->buf, n);
if (err)
goto Efault;
copied += n;
m->count -= n;
if (m->count)
m->from = n;
else
pos++;
m->index = pos;
Done:
if (!copied)
copied = err;
else {
*ppos += copied;
m->read_pos += copied;
}
file->f_version = m->version;
mutex_unlock(&m->lock);
return copied;
Enomem:
err = -ENOMEM;
goto Done;
Efault:
err = -EFAULT;
goto Done;
}
static int
create_pagelist(char __user *buf, size_t count, unsigned short type,
struct task_struct *task, PAGELIST_T ** ppagelist)
{
PAGELIST_T *pagelist;
struct page **pages;
struct page *page;
unsigned long *addrs;
unsigned int num_pages, offset, i;
char *addr, *base_addr, *next_addr;
int run, addridx, actual_pages;
unsigned long *need_release;
offset = (unsigned int)buf & (PAGE_SIZE - 1);
num_pages = (count + offset + PAGE_SIZE - 1) / PAGE_SIZE;
*ppagelist = NULL;
/* Allocate enough storage to hold the page pointers and the page
** list
*/
pagelist = kmalloc(sizeof(PAGELIST_T) +
(num_pages * sizeof(unsigned long)) +
sizeof(unsigned long) +
(num_pages * sizeof(pages[0])),
GFP_KERNEL);
vchiq_log_trace(vchiq_arm_log_level,
"create_pagelist - %x", (unsigned int)pagelist);
if (!pagelist)
return -ENOMEM;
addrs = pagelist->addrs;
need_release = (unsigned long *)(addrs + num_pages);
pages = (struct page **)(addrs + num_pages + 1);
if (is_vmalloc_addr(buf)) {
for (actual_pages = 0; actual_pages < num_pages; actual_pages++) {
pages[actual_pages] = vmalloc_to_page(buf + (actual_pages * PAGE_SIZE));
}
*need_release = 0; /* do not try and release vmalloc pages */
} else {
down_read(&task->mm->mmap_sem);
actual_pages = get_user_pages(task, task->mm,
(unsigned long)buf & ~(PAGE_SIZE - 1),
num_pages,
(type == PAGELIST_READ) /*Write */ ,
0 /*Force */ ,
pages,
NULL /*vmas */);
up_read(&task->mm->mmap_sem);
if (actual_pages != num_pages) {
vchiq_log_info(vchiq_arm_log_level,
"create_pagelist - only %d/%d pages locked",
actual_pages,
num_pages);
/* This is probably due to the process being killed */
while (actual_pages > 0)
{
actual_pages--;
page_cache_release(pages[actual_pages]);
}
kfree(pagelist);
if (actual_pages == 0)
actual_pages = -ENOMEM;
return actual_pages;
}
*need_release = 1; /* release user pages */
}
pagelist->length = count;
pagelist->type = type;
pagelist->offset = offset;
/* Group the pages into runs of contiguous pages */
base_addr = VCHIQ_ARM_ADDRESS(page_address(pages[0]));
next_addr = base_addr + PAGE_SIZE;
addridx = 0;
run = 0;
for (i = 1; i < num_pages; i++) {
addr = VCHIQ_ARM_ADDRESS(page_address(pages[i]));
if ((addr == next_addr) && (run < (PAGE_SIZE - 1))) {
next_addr += PAGE_SIZE;
run++;
} else {
addrs[addridx] = (unsigned long)base_addr + run;
addridx++;
base_addr = addr;
next_addr = addr + PAGE_SIZE;
run = 0;
}
}
addrs[addridx] = (unsigned long)base_addr + run;
addridx++;
/* Partial cache lines (fragments) require special measures */
if ((type == PAGELIST_READ) &&
((pagelist->offset & (CACHE_LINE_SIZE - 1)) ||
((pagelist->offset + pagelist->length) &
(CACHE_LINE_SIZE - 1)))) {
FRAGMENTS_T *fragments;
if (down_interruptible(&g_free_fragments_sema) != 0) {
kfree(pagelist);
return -EINTR;
}
WARN_ON(g_free_fragments == NULL);
down(&g_free_fragments_mutex);
fragments = (FRAGMENTS_T *) g_free_fragments;
WARN_ON(fragments == NULL);
g_free_fragments = *(FRAGMENTS_T **) g_free_fragments;
up(&g_free_fragments_mutex);
pagelist->type =
PAGELIST_READ_WITH_FRAGMENTS + (fragments -
g_fragments_base);
}
for (page = virt_to_page(pagelist);
page <= virt_to_page(addrs + num_pages - 1); page++) {
flush_dcache_page(page);
}
*ppagelist = pagelist;
return 0;
}
void foo(void) {
is_vmalloc_addr(NULL);
}
