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fix a kmap leak in virtio_console

While we are at it, don't do kmap() under kmap_atomic(), *especially* for a page we'd allocated with GFP_KERNEL. It's spelled "page_address", and had that been more than that, we'd have a real trouble - kmap_high() can block, and doing that while holding kmap_atomic() is a Bad Idea(tm).

Al Viro committed 12 years ago

Commit c9efe511 parent d311d791 file · +3 −6Browse files

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drivers/char/virtio_console.c+3−6
@@ -890,12 +890,10 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf, · 889 unmodified lines
890 } else {890 } else {
891 /* Failback to copying a page */891 /* Failback to copying a page */
892 struct page *page = alloc_page(GFP_KERNEL);892 struct page *page = alloc_page(GFP_KERNEL);
893 char *src = buf->ops->map(pipe, buf, 1);893 char *src;
894 char *dst;
895 894
896 if (!page)895 if (!page)
897 return -ENOMEM;896 return -ENOMEM;
898 dst = kmap(page);
899 897
900 offset = sd->pos & ~PAGE_MASK;898 offset = sd->pos & ~PAGE_MASK;
901 899
@@ -903,9 +901,8 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf, · 1 unmodified line
903 if (len + offset > PAGE_SIZE)901 if (len + offset > PAGE_SIZE)
904 len = PAGE_SIZE - offset;902 len = PAGE_SIZE - offset;
905 903
906 memcpy(dst + offset, src + buf->offset, len);904 src = buf->ops->map(pipe, buf, 1);
907 905 memcpy(page_address(page) + offset, src + buf->offset, len);
908 kunmap(page);
909 buf->ops->unmap(pipe, buf, src);906 buf->ops->unmap(pipe, buf, src);
910 907
911 sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);908 sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);