Return early on partial read/write, which may happen in future. (eg. hit hwpoison pages) CC: Greg KH CC: Andi Kleen CC: KAMEZAWA Hiroyuki Signed-off-by: Wu Fengguang --- drivers/char/mem.c | 30 ++++++++++++++++++------------ mm/vmalloc.c | 10 +--------- 2 files changed, 19 insertions(+), 21 deletions(-) --- linux-mm.orig/drivers/char/mem.c 2009-09-15 09:44:49.000000000 +0800 +++ linux-mm/drivers/char/mem.c 2009-09-15 09:44:55.000000000 +0800 @@ -444,18 +444,22 @@ static ssize_t read_kmem(struct file *fi if (!kbuf) return -ENOMEM; while (count > 0) { + unsigned long n; + sz = size_inside_page(p, count); - sz = vread(kbuf, (char *)p, sz); - if (!sz) + n = vread(kbuf, (char *)p, sz); + if (!n) break; - if (copy_to_user(buf, kbuf, sz)) { + if (copy_to_user(buf, kbuf, n)) { free_page((unsigned long)kbuf); return -EFAULT; } - count -= sz; - buf += sz; - read += sz; - p += sz; + count -= n; + buf += n; + read += n; + p += n; + if (n < sz) + break; } free_page((unsigned long)kbuf); } @@ -551,11 +555,13 @@ static ssize_t write_kmem(struct file * free_page((unsigned long)kbuf); return -EFAULT; } - sz = vwrite(kbuf, (char *)p, sz); - count -= sz; - buf += sz; - virtr += sz; - p += sz; + n = vwrite(kbuf, (char *)p, sz); + count -= n; + buf += n; + virtr += n; + p += n; + if (n < sz) + break; } free_page((unsigned long)kbuf); } -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/