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process_vm_access: don't bother with returning the amounts of bytes copied 

we can calculate that in the caller just fine, TYVM

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-02-05 13:15:28 -05:00
parent e21345f9c3
commit 9acc1a0f9a
1 changed files with 16 additions and 31 deletions
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47
mm/process_vm_access.c
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@ -43,13 +43,10 @@ static int process_vm_rw_pages(struct page **pages,
unsigned offset, unsigned offset,
size_t len, size_t len,
struct iov_iter *iter, struct iov_iter *iter,
int vm_write, int vm_write)
ssize_t *bytes_copied)
{ {
*bytes_copied = 0;
/* Do the copy for each page */ /* Do the copy for each page */
while (iov_iter_count(iter) && len) { while (len && iov_iter_count(iter)) {
struct page *page = *pages++; struct page *page = *pages++;
size_t copy = PAGE_SIZE - offset; size_t copy = PAGE_SIZE - offset;
size_t copied; size_t copied;
@ -67,7 +64,6 @@ static int process_vm_rw_pages(struct page **pages,
} else { } else {
copied = copy_page_to_iter(page, offset, copy, iter); copied = copy_page_to_iter(page, offset, copy, iter);
} }
*bytes_copied += copied;
len -= copied; len -= copied;
if (copied < copy && iov_iter_count(iter)) if (copied < copy && iov_iter_count(iter))
return -EFAULT; return -EFAULT;
@ -101,20 +97,16 @@ static int process_vm_rw_single_vec(unsigned long addr,
struct page **process_pages, struct page **process_pages,
struct mm_struct *mm, struct mm_struct *mm,
struct task_struct *task, struct task_struct *task,
int vm_write, int vm_write)
ssize_t *bytes_copied)
{ {
unsigned long pa = addr & PAGE_MASK; unsigned long pa = addr & PAGE_MASK;
unsigned long start_offset = addr - pa; unsigned long start_offset = addr - pa;
unsigned long nr_pages; unsigned long nr_pages;
ssize_t bytes_copied_loop;
ssize_t rc = 0; ssize_t rc = 0;
unsigned long nr_pages_copied = 0; unsigned long nr_pages_copied = 0;
unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
/ sizeof(struct pages *); / sizeof(struct pages *);
*bytes_copied = 0;
/* Work out address and page range required */ /* Work out address and page range required */
if (len == 0) if (len == 0)
return 0; return 0;
@ -143,11 +135,9 @@ static int process_vm_rw_single_vec(unsigned long addr,
rc = process_vm_rw_pages(process_pages, rc = process_vm_rw_pages(process_pages,
start_offset, n, iter, start_offset, n, iter,
vm_write, vm_write);
&bytes_copied_loop);
len -= n; len -= n;
start_offset = 0; start_offset = 0;
*bytes_copied += bytes_copied_loop;
nr_pages_copied += pages_pinned; nr_pages_copied += pages_pinned;
pa += pages_pinned * PAGE_SIZE; pa += pages_pinned * PAGE_SIZE;
while (pages_pinned) while (pages_pinned)
@ -187,11 +177,10 @@ static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
struct mm_struct *mm; struct mm_struct *mm;
unsigned long i; unsigned long i;
ssize_t rc = 0; ssize_t rc = 0;
ssize_t bytes_copied_loop;
ssize_t bytes_copied = 0;
unsigned long nr_pages = 0; unsigned long nr_pages = 0;
unsigned long nr_pages_iov; unsigned long nr_pages_iov;
ssize_t iov_len; ssize_t iov_len;
size_t total_len = iov_iter_count(iter);
/* /*
* Work out how many pages of struct pages we're going to need * Work out how many pages of struct pages we're going to need
@ -245,24 +234,20 @@ static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
goto put_task_struct; goto put_task_struct;
} }
for (i = 0; i < riovcnt && iov_iter_count(iter); i++) { for (i = 0; i < riovcnt && iov_iter_count(iter) && !rc; i++)
rc = process_vm_rw_single_vec( rc = process_vm_rw_single_vec(
(unsigned long)rvec[i].iov_base, rvec[i].iov_len, (unsigned long)rvec[i].iov_base, rvec[i].iov_len,
iter, process_pages, mm, task, vm_write, iter, process_pages, mm, task, vm_write);
&bytes_copied_loop);
bytes_copied += bytes_copied_loop; /* copied = space before - space after */
if (rc != 0) { total_len -= iov_iter_count(iter);
/* If we have managed to copy any data at all then
we return the number of bytes copied. Otherwise /* If we have managed to copy any data at all then
we return the error code */ we return the number of bytes copied. Otherwise
if (bytes_copied) we return the error code */
rc = bytes_copied; if (total_len)
goto put_mm; rc = total_len;
}
}
rc = bytes_copied;
put_mm:
mmput(mm); mmput(mm);
put_task_struct: put_task_struct: