Quoting Matt Helsley (matthltc@xxxxxxxxxx):
> Save/restore epoll items during checkpoint/restart respectively.
> kmalloc failures should be dealt with more kindly than just error-out
> because epoll is made to poll many thousands of file descriptors.
> Subsequent patches will change epoll c/r to "chunk" its output/input
> respectively.
>
> Signed-off-by: Matt Helsley <matthltc@xxxxxxxxxx>
Haven't looked much at epoll, but it looks good...
> +struct file* ep_file_restore(struct ckpt_ctx *ctx,
> + struct ckpt_hdr_file *h)
> +{
> + struct file *epfile;
> + int epfd, ret;
> +
> + if (h->h.type != CKPT_HDR_FILE ||
> + h->h.len != sizeof(*h) ||
> + h->f_type != CKPT_FILE_EPOLL)
> + return ERR_PTR(-EINVAL);
> +
> + epfd = sys_epoll_create1(h->f_flags & EPOLL_CLOEXEC);
> + if (epfd < 0)
> + return ERR_PTR(epfd);
> + epfile = fget(epfd);
> + BUG_ON(!epfile);
> +
> + /*
> + * Needed before we can properly restore the watches and enforce the
> + * limit on watch numbers.
> + */
> + ret = restore_file_common(ctx, epfile, h);
> + if (ret < 0)
> + goto fput_out;
> +
> + /*
> + * Defer restoring the epoll items until the file table is
> + * fully restored. Ensures that valid file objrefs will resolve.
> + */
> + ret = deferqueue_add_ptr(ctx->files_deferq, ctx, ep_items_restore, NULL);
> + if (ret < 0) {
> +fput_out:
I've heard complaints before about labels in the middle of an
if block. Since we know ret < 0 at the goto, the label could
just as well go up one line...
> + fput(epfile);
> + epfile = ERR_PTR(ret);
> + }
> + sys_close(epfd); /* harmless even if an error occured */
> + return epfile;
> +}
> +
> +#endif /* CONFIG_CHECKPOINT */
> +
> static int __init eventpoll_init(void)
> {
> struct sysinfo si;
> diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
> index e00dd70..a8594cc 100644
> --- a/include/linux/checkpoint.h
> +++ b/include/linux/checkpoint.h
> @@ -72,6 +72,7 @@ extern int _ckpt_read_obj_type(struct ckpt_ctx *ctx,
> void *ptr, int len, int type);
> extern int _ckpt_read_buffer(struct ckpt_ctx *ctx, void *ptr, int len);
> extern int _ckpt_read_string(struct ckpt_ctx *ctx, void *ptr, int len);
> +extern void *ckpt_read_obj(struct ckpt_ctx *ctx, int len, int max);
> extern void *ckpt_read_obj_type(struct ckpt_ctx *ctx, int len, int type);
> extern void *ckpt_read_buf_type(struct ckpt_ctx *ctx, int len, int type);
> extern int ckpt_read_payload(struct ckpt_ctx *ctx,
> diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
> index 2ed523f..48736bd 100644
> --- a/include/linux/checkpoint_hdr.h
> +++ b/include/linux/checkpoint_hdr.h
> @@ -85,6 +85,7 @@ enum {
> CKPT_HDR_PIPE_BUF,
> CKPT_HDR_TTY,
> CKPT_HDR_TTY_LDISC,
> + CKPT_HDR_EPOLL_ITEMS = 391, /* Follows file-table */
Hmm, why are you specifying the number here? That's just
begging for conflicts with other people's patches...
>
> CKPT_HDR_MM = 401,
> CKPT_HDR_VMA,
> @@ -380,6 +381,7 @@ enum file_type {
> CKPT_FILE_FIFO,
> CKPT_FILE_SOCKET,
> CKPT_FILE_TTY,
> + CKPT_FILE_EPOLL,
> CKPT_FILE_MAX
> };
>
> @@ -475,6 +477,18 @@ struct ckpt_hdr_file_socket {
> __s32 sock_objref;
> } __attribute__((aligned(8)));
>
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