diff options
| -rw-r--r-- | fs/splice.c | 28 | ||||
| -rw-r--r-- | include/linux/pipe_fs_i.h | 2 |
2 files changed, 27 insertions, 3 deletions
diff --git a/fs/splice.c b/fs/splice.c index d4664a2..b150493 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -141,7 +141,10 @@ static struct pipe_buf_operations page_cache_pipe_buf_ops = { static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { - return 1; + if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) + return 1; + + return 0; } static struct pipe_buf_operations user_page_pipe_buf_ops = { @@ -186,6 +189,9 @@ static ssize_t splice_to_pipe(struct pipe_inode_info *pipe, buf->offset = spd->partial[page_nr].offset; buf->len = spd->partial[page_nr].len; buf->ops = spd->ops; + if (spd->flags & SPLICE_F_GIFT) + buf->flags |= PIPE_BUF_FLAG_GIFT; + pipe->nrbufs++; page_nr++; ret += buf->len; @@ -1073,7 +1079,7 @@ static long do_splice(struct file *in, loff_t __user *off_in, */ static int get_iovec_page_array(const struct iovec __user *iov, unsigned int nr_vecs, struct page **pages, - struct partial_page *partial) + struct partial_page *partial, int aligned) { int buffers = 0, error = 0; @@ -1113,6 +1119,15 @@ static int get_iovec_page_array(const struct iovec __user *iov, * in the user pages. */ off = (unsigned long) base & ~PAGE_MASK; + + /* + * If asked for alignment, the offset must be zero and the + * length a multiple of the PAGE_SIZE. + */ + error = -EINVAL; + if (aligned && (off || len & ~PAGE_MASK)) + break; + npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; if (npages > PIPE_BUFFERS - buffers) npages = PIPE_BUFFERS - buffers; @@ -1206,7 +1221,8 @@ static long do_vmsplice(struct file *file, const struct iovec __user *iov, else if (unlikely(!nr_segs)) return 0; - spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial); + spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, + flags & SPLICE_F_GIFT); if (spd.nr_pages <= 0) return spd.nr_pages; @@ -1314,6 +1330,12 @@ static int link_pipe(struct pipe_inode_info *ipipe, obuf = opipe->bufs + nbuf; *obuf = *ibuf; + /* + * Don't inherit the gift flag, we need to + * prevent multiple steals of this page. + */ + obuf->flags &= ~PIPE_BUF_FLAG_GIFT; + if (obuf->len > len) obuf->len = len; diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index 4c05449..df4d3fa 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -7,6 +7,7 @@ #define PIPE_BUF_FLAG_LRU 0x01 /* page is on the LRU */ #define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */ +#define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */ struct pipe_buffer { struct page *page; @@ -79,6 +80,7 @@ int generic_pipe_buf_pin(struct pipe_inode_info *, struct pipe_buffer *); /* we may still block on the fd we splice */ /* from/to, of course */ #define SPLICE_F_MORE (0x04) /* expect more data */ +#define SPLICE_F_GIFT (0x08) /* pages passed in are a gift */ /* * Passed to the actors |