Commit d4690f1e authored by Al Viro's avatar Al Viro Committed by Linus Torvalds
Browse files

fix iov_iter_fault_in_readable() 



... by turning it into what used to be multipages counterpart

Cc: stable@vger.kernel.org
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f32a10df

include/linux/uio.h

+1 −1
Original line number Diff line number Diff line
@@ -76,7 +76,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page, 
		struct iov_iter *i, unsigned long offset, size_t bytes);

void iov_iter_advance(struct iov_iter *i, size_t bytes);

int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);

int iov_iter_fault_in_multipages_readable(struct iov_iter *i, size_t bytes);

#define iov_iter_fault_in_multipages_readable iov_iter_fault_in_readable

size_t iov_iter_single_seg_count(const struct iov_iter *i);

size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,

			 struct iov_iter *i);

lib/iov_iter.c

+2 −22
Original line number Diff line number Diff line
@@ -290,26 +290,6 @@ static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t 
	return wanted - bytes;

}



/*

 * Fault in the first iovec of the given iov_iter, to a maximum length

 * of bytes. Returns 0 on success, or non-zero if the memory could not be

 * accessed (ie. because it is an invalid address).

 *

 * writev-intensive code may want this to prefault several iovecs -- that

 * would be possible (callers must not rely on the fact that _only_ the

 * first iovec will be faulted with the current implementation).

 */

int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)

{

	if (!(i->type & (ITER_BVEC|ITER_KVEC))) {

		char __user *buf = i->iov->iov_base + i->iov_offset;

		bytes = min(bytes, i->iov->iov_len - i->iov_offset);

		return fault_in_pages_readable(buf, bytes);

	}

	return 0;

}

EXPORT_SYMBOL(iov_iter_fault_in_readable);



/*

 * Fault in one or more iovecs of the given iov_iter, to a maximum length of

 * bytes.  For each iovec, fault in each page that constitutes the iovec.
@@ -317,7 +297,7 @@ EXPORT_SYMBOL(iov_iter_fault_in_readable); 
 * Return 0 on success, or non-zero if the memory could not be accessed (i.e.

 * because it is an invalid address).

 */

int iov_iter_fault_in_multipages_readable(struct iov_iter *i, size_t bytes)

int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)

{

	size_t skip = i->iov_offset;

	const struct iovec *iov;
@@ -334,7 +314,7 @@ int iov_iter_fault_in_multipages_readable(struct iov_iter *i, size_t bytes) 
	}

	return 0;

}

EXPORT_SYMBOL(iov_iter_fault_in_multipages_readable);

EXPORT_SYMBOL(iov_iter_fault_in_readable);



void iov_iter_init(struct iov_iter *i, int direction,

			const struct iovec *iov, unsigned long nr_segs,