On Mon, Mar 22, 2010 at 08:12:45PM -0400, Oren Laadan wrote: > On Mon, 22 Mar 2010, Nick Piggin wrote: > > > On Thu, Mar 18, 2010 at 08:59:45PM -0400, Oren Laadan wrote: > > > These two are used in the next patch when calling vfs_read/write() > > > > Said next patch didn't seem to make it to fsdevel. > > Thanks for reviewing, and sorry about this glitch - see below. > > > > > Should it at least go to fs/internal.h? > > Sure. > > So Here is the relevant hunk from said patch (the entire > patch is: https://patchwork.kernel.org/patch/86389/): > > +/* > + * Helpers to write(read) from(to) kernel space to(from) the checkpoint > + * image file descriptor (similar to how a core-dump is performed). > + * > + * ckpt_kwrite() - write a kernel-space buffer to the checkpoint image > + * ckpt_kread() - read from the checkpoint image to a kernel-space buffer Hmm, OK. Slightly-more-write(2) type of write. fs/splice.c code also has a kernel_write and readv. Not sure if there is any other common code. But maybe it would be better to put together some useful helpers under fs/ rather than a ckpt specific thing. > + */ > + > +static inline int _ckpt_kwrite(struct file *file, void *addr, int count) > +{ > + void __user *uaddr = (__force void __user *) addr; > + ssize_t nwrite; > + int nleft; > + > + for (nleft = count; nleft; nleft -= nwrite) { > + loff_t pos = file_pos_read(file); > + nwrite = vfs_write(file, uaddr, nleft, &pos); > + file_pos_write(file, pos); > + if (nwrite < 0) { > + if (nwrite == -EAGAIN) > + nwrite = 0; > + else > + return nwrite; > + } > + uaddr += nwrite; > + } > + return 0; > +} > + > +int ckpt_kwrite(struct ckpt_ctx *ctx, void *addr, int count) > +{ > + mm_segment_t fs; > + int ret; > + > + fs = get_fs(); > + set_fs(KERNEL_DS); > + ret = _ckpt_kwrite(ctx->file, addr, count); > + set_fs(fs); > + > + ctx->total += count; > + return ret; > +} > + > +static inline int _ckpt_kread(struct file *file, void *addr, int count) > +{ > + void __user *uaddr = (__force void __user *) addr; > + ssize_t nread; > + int nleft; > + > + for (nleft = count; nleft; nleft -= nread) { > + loff_t pos = file_pos_read(file); > + nread = vfs_read(file, uaddr, nleft, &pos); > + file_pos_write(file, pos); > + if (nread <= 0) { > + if (nread == -EAGAIN) { > + nread = 0; > + continue; > + } else if (nread == 0) > + nread = -EPIPE; /* unexecpted EOF */ > + return nread; > + } > + uaddr += nread; > + } > + return 0; > +} > + > +int ckpt_kread(struct ckpt_ctx *ctx, void *addr, int count) > +{ > + mm_segment_t fs; > + int ret; > + > + fs = get_fs(); > + set_fs(KERNEL_DS); > + ret = _ckpt_kread(ctx->file , addr, count); > + set_fs(fs); > + > + ctx->total += count; > + return ret; > +} > > Oren. > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
