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 + */ + +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
