| Message ID | 1595218658-53727-1-git-send-email-w@laoqinren.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v1] xarray: update document for error space returned by xarray normal API | expand |
On Mon, Jul 20, 2020 at 12:17:38PM +0800, Wang Long wrote: > In the current xarray code, the negative value -1 and -4095 represented > as an error. > > xa_is_err(xa_mk_internal(-4095)) and xa_is_err(xa_mk_internal(-1)) > are all return true. > > This patch update the document. There are actually three distinct problems here, but none of them are fixed by this patch. The first is that there's no test-suite coverage for this. The second is that xa_is_err() is checking against -MAX_ERRNO instead of -1023. The third is that the documentation isn't clear enough because the line you're correcting is accurate. I don't think any of these three problems is terribly urgent to fix. The second is most important because it could lead to confusion between an xa_node that happens to be allocated at the top of memory and an error return, but I don't think there is ever a situation where we end up checking a node entry for being an error entry. I may be wrong. The solution to the first problem probably looks like this: +++ b/lib/test_xarray.c @@ -81,6 +81,11 @@ static void *xa_store_order(struct xarray *xa, unsigned long index, static noinline void check_xa_err(struct xarray *xa) { + XA_BUG_ON(xa, xa_is_err(xa_mk_internal(0))); + XA_BUG_ON(xa, !xa_is_err(xa_mk_internal(-1))); + XA_BUG_ON(xa, !xa_is_err(xa_mk_internal(-1023))); + XA_BUG_ON(xa, xa_is_err(xa_mk_internal(-1024))); + XA_BUG_ON(xa, xa_err(xa_store_index(xa, 0, GFP_NOWAIT)) != 0); XA_BUG_ON(xa, xa_err(xa_erase(xa, 0)) != 0); #ifndef __KERNEL__ > Signed-off-by: Wang Long <w@laoqinren.net> > --- > include/linux/xarray.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/xarray.h b/include/linux/xarray.h > index b4d70e7..0588fb9 100644 > --- a/include/linux/xarray.h > +++ b/include/linux/xarray.h > @@ -36,7 +36,7 @@ > * 257: Zero entry > * > * Errors are also represented as internal entries, but use the negative > - * space (-4094 to -2). They're never stored in the slots array; only > + * space (-4095 to -1). They're never stored in the slots array; only > * returned by the normal API. > */ > > -- > 1.8.3.1 > > > >
diff --git a/include/linux/xarray.h b/include/linux/xarray.h index b4d70e7..0588fb9 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -36,7 +36,7 @@ * 257: Zero entry * * Errors are also represented as internal entries, but use the negative - * space (-4094 to -2). They're never stored in the slots array; only + * space (-4095 to -1). They're never stored in the slots array; only * returned by the normal API. */
In the current xarray code, the negative value -1 and -4095 represented as an error. xa_is_err(xa_mk_internal(-4095)) and xa_is_err(xa_mk_internal(-1)) are all return true. This patch update the document. Signed-off-by: Wang Long <w@laoqinren.net> --- include/linux/xarray.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)