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Commit 9f78bdfa authored by Al Viro's avatar Al Viro
Browse files

process_vm_access: switch to iov_iter 



instead of keeping its pieces in separate variables and passing
pointers to all of them...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 1291afc1

mm/process_vm_access.c

+28 −34
Original line number Diff line number Diff line
@@ -45,9 +45,7 @@ static int process_vm_rw_pages(struct task_struct *task, 
			       unsigned long pa,

			       unsigned long start_offset,

			       unsigned long len,

			       const struct iovec **iovp,

			       unsigned long *left,

			       size_t *lvec_offset,

			       struct iov_iter *iter,

			       int vm_write,

			       unsigned int nr_pages_to_copy,

			       ssize_t *bytes_copied)
@@ -59,7 +57,7 @@ static int process_vm_rw_pages(struct task_struct *task, 
	int ret;

	ssize_t bytes_to_copy;

	ssize_t rc = 0;

	const struct iovec *iov = *iovp;

	const struct iovec *iov = iter->iov;



	*bytes_copied = 0;
@@ -77,14 +75,14 @@ static int process_vm_rw_pages(struct task_struct *task, 


	/* Do the copy for each page */

	for (pgs_copied = 0;

	     (pgs_copied < nr_pages_to_copy) && *left;

	     (pgs_copied < nr_pages_to_copy) && iter->nr_segs;

	     pgs_copied++) {

		/* Make sure we have a non zero length iovec */

		while (*left && iov->iov_len == 0) {

		while (iter->nr_segs && iov->iov_len == 0) {

			iov++;

			(*left)--;

			iter->nr_segs--;

		}

		if (!*left)

		if (!iter->nr_segs)

			break;



		/*
@@ -96,18 +94,18 @@ static int process_vm_rw_pages(struct task_struct *task, 
				      len - *bytes_copied);

		bytes_to_copy = min_t(ssize_t, bytes_to_copy,

				      iov->iov_len

				      - *lvec_offset);

				      - iter->iov_offset);



		target_kaddr = kmap(process_pages[pgs_copied]) + start_offset;



		if (vm_write)

			ret = copy_from_user(target_kaddr,

					     iov->iov_base

					     + *lvec_offset,

					     + iter->iov_offset,

					     bytes_to_copy);

		else

			ret = copy_to_user(iov->iov_base

					   + *lvec_offset,

					   + iter->iov_offset,

					   target_kaddr, bytes_to_copy);

		kunmap(process_pages[pgs_copied]);

		if (ret) {
@@ -117,15 +115,15 @@ static int process_vm_rw_pages(struct task_struct *task, 
			goto end;

		}

		*bytes_copied += bytes_to_copy;

		*lvec_offset += bytes_to_copy;

		if (*lvec_offset == iov->iov_len) {

		iter->iov_offset += bytes_to_copy;

		if (iter->iov_offset == iov->iov_len) {

			/*

			 * Need to copy remaining part of page into the

			 * next iovec if there are any bytes left in page

			 */

			(*left)--;

			iter->nr_segs--;

			iov++;

			*lvec_offset = 0;

			iter->iov_offset = 0;

			start_offset = (start_offset + bytes_to_copy)

				% PAGE_SIZE;

			if (start_offset)
@@ -147,7 +145,7 @@ static int process_vm_rw_pages(struct task_struct *task, 
			put_page(process_pages[j]);

	}



	*iovp = iov;

	iter->iov = iov;

	return rc;

}
@@ -172,9 +170,7 @@ static int process_vm_rw_pages(struct task_struct *task, 
 */

static int process_vm_rw_single_vec(unsigned long addr,

				    unsigned long len,

				    const struct iovec **iovp,

				    unsigned long *left,

				    size_t *lvec_offset,

				    struct iov_iter *iter,

				    struct page **process_pages,

				    struct mm_struct *mm,

				    struct task_struct *task,
@@ -198,14 +194,12 @@ static int process_vm_rw_single_vec(unsigned long addr, 
		return 0;

	nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;



	while ((nr_pages_copied < nr_pages) && *left) {

	while ((nr_pages_copied < nr_pages) && iter->nr_segs) {

		nr_pages_to_copy = min(nr_pages - nr_pages_copied,

				       max_pages_per_loop);



		rc = process_vm_rw_pages(task, mm, process_pages, pa,

					 start_offset, len,

					 iovp, left,

					 lvec_offset,

					 start_offset, len, iter,

					 vm_write, nr_pages_to_copy,

					 &bytes_copied_loop);

		start_offset = 0;
@@ -240,8 +234,7 @@ static int process_vm_rw_single_vec(unsigned long addr, 
 *  return less bytes than expected if an error occurs during the copying

 *  process.

 */

static ssize_t process_vm_rw_core(pid_t pid, const struct iovec *lvec,

				  unsigned long liovcnt,

static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,

				  const struct iovec *rvec,

				  unsigned long riovcnt,

				  unsigned long flags, int vm_write)
@@ -256,8 +249,6 @@ static ssize_t process_vm_rw_core(pid_t pid, const struct iovec *lvec, 
	ssize_t bytes_copied = 0;

	unsigned long nr_pages = 0;

	unsigned long nr_pages_iov;

	unsigned long left = liovcnt;

	size_t iov_l_curr_offset = 0;

	ssize_t iov_len;



	/*
@@ -312,11 +303,11 @@ static ssize_t process_vm_rw_core(pid_t pid, const struct iovec *lvec, 
		goto put_task_struct;

	}



	for (i = 0; i < riovcnt && left; i++) {

	for (i = 0; i < riovcnt && iter->nr_segs; i++) {

		rc = process_vm_rw_single_vec(

			(unsigned long)rvec[i].iov_base, rvec[i].iov_len,

			&lvec, &left, &iov_l_curr_offset,

			process_pages, mm, task, vm_write, &bytes_copied_loop);

			iter, process_pages, mm, task, vm_write,

			&bytes_copied_loop);

		bytes_copied += bytes_copied_loop;

		if (rc != 0) {

			/* If we have managed to copy any data at all then
@@ -365,6 +356,7 @@ static ssize_t process_vm_rw(pid_t pid, 
	struct iovec iovstack_r[UIO_FASTIOV];

	struct iovec *iov_l = iovstack_l;

	struct iovec *iov_r = iovstack_r;

	struct iov_iter iter;

	ssize_t rc;



	if (flags != 0)
@@ -380,13 +372,14 @@ static ssize_t process_vm_rw(pid_t pid, 
	if (rc <= 0)

		goto free_iovecs;



	iov_iter_init(&iter, iov_l, liovcnt, rc, 0);



	rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,

				   iovstack_r, &iov_r);

	if (rc <= 0)

		goto free_iovecs;



	rc = process_vm_rw_core(pid, iov_l, liovcnt, iov_r, riovcnt, flags,

				vm_write);

	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);



free_iovecs:

	if (iov_r != iovstack_r)
@@ -426,6 +419,7 @@ compat_process_vm_rw(compat_pid_t pid, 
	struct iovec iovstack_r[UIO_FASTIOV];

	struct iovec *iov_l = iovstack_l;

	struct iovec *iov_r = iovstack_r;

	struct iov_iter iter;

	ssize_t rc = -EFAULT;



	if (flags != 0)
@@ -441,14 +435,14 @@ compat_process_vm_rw(compat_pid_t pid, 
						  &iov_l);

	if (rc <= 0)

		goto free_iovecs;

	iov_iter_init(&iter, iov_l, liovcnt, rc, 0);

	rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,

					  UIO_FASTIOV, iovstack_r,

					  &iov_r);

	if (rc <= 0)

		goto free_iovecs;



	rc = process_vm_rw_core(pid, iov_l, liovcnt, iov_r, riovcnt, flags,

			   vm_write);

	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);



free_iovecs:

	if (iov_r != iovstack_r)