Messages in this thread Patch in this message | | | Date | Sat, 4 Mar 2006 22:15:50 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] adjust /dev/{kmem,mem,port} write handlers |
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"Jan Beulich" <JBeulich@novell.com> wrote: > > The /dev/mem and /dev/kmem write handlers weren't fully POSIX compliant in > that they wouldn't always force the file pointer to be updated when returning > success status. > The /dev/port write handler was inconsistent with the /dev/mem and /dev/kmem > handlers in that when encountering a -EFAULT condition after already having > written a number of items it would return -EFAULT rather than the number of > bytes written. > > ... > > @@ -514,11 +510,10 @@ static ssize_t write_kmem(struct file * > if (len) { > written = copy_from_user(kbuf, buf, len); > if (written) { > - ssize_t ret; > - > + if (wrote + virtr) > + break; > free_page((unsigned long)kbuf); > - ret = wrote + virtr + (len - written); > - return ret ? ret : -EFAULT; > + return -EFAULT; > } > } > len = vwrite(kbuf, (char *)p, len);
I think write_kmem() still isn't quie right - it needs to update `p' (and hence *ppos) to account for a partial copy_from_user(). (Please double-check)
--- devel/drivers/char/mem.c~adjust-dev-kmemmemport-write-handlers-fix 2006-03-04 22:10:55.000000000 -0800 +++ devel-akpm/drivers/char/mem.c 2006-03-04 22:15:19.000000000 -0800 @@ -504,8 +504,11 @@ static ssize_t write_kmem(struct file * if (len) { written = copy_from_user(kbuf, buf, len); if (written) { - if (wrote + virtr) + if (wrote + virtr) { + p += len - written; + virtr += len - written; break; + } free_page((unsigned long)kbuf); return -EFAULT; } _ - 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/
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