Message ID | 1504634367.15310.59.camel@edumazet-glaptop3.roam.corp.google.com |
---|---|
State | Not Applicable, archived |
Delegated to: | David Miller |
Headers | show |
Series | radix-tree: must check __radix_tree_preload() return value | expand |
On Tue, Sep 5, 2017 at 10:59 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > @@ -2104,7 +2104,10 @@ EXPORT_SYMBOL(radix_tree_tagged); > */ > void idr_preload(gfp_t gfp_mask) > { > - __radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE); > + int ret = __radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE); > + > + if (ret) > + preempt_disable(); > } > EXPORT_SYMBOL(idr_preload); Is there a reason for the "ret" variable that is entirely mis-named, since it's never actually used as a return value? (Sure. it's the return value of a function, but that is entirely useless and pointless information, and adds no value. We should name variables by the data they contain or how they are used, not by "it was the return value of a function"). In other words, why isn't this just if (__radix_tree_preload(..)) preempt_disable(); which is shorter and clearer and not confusing? > @@ -2118,13 +2121,14 @@ EXPORT_SYMBOL(idr_preload); > */ > int ida_pre_get(struct ida *ida, gfp_t gfp) > { > - __radix_tree_preload(gfp, IDA_PRELOAD_SIZE); > + int ret = __radix_tree_preload(gfp, IDA_PRELOAD_SIZE); > /* > * The IDA API has no preload_end() equivalent. Instead, > * ida_get_new() can return -EAGAIN, prompting the caller > * to return to the ida_pre_get() step. > */ > - preempt_enable(); > + if (!ret) > + preempt_enable(); Same issue, but this time strengthened by an additional "why doesn't this just use that idr_preload function then?" question.. Linus
On Tue, 2017-09-05 at 11:07 -0700, Linus Torvalds wrote: > On Tue, Sep 5, 2017 at 10:59 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > > @@ -2104,7 +2104,10 @@ EXPORT_SYMBOL(radix_tree_tagged); > > */ > > void idr_preload(gfp_t gfp_mask) > > { > > - __radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE); > > + int ret = __radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE); > > + > > + if (ret) > > + preempt_disable(); > > } > > EXPORT_SYMBOL(idr_preload); > > Is there a reason for the "ret" variable that is entirely mis-named, > since it's never actually used as a return value? > > (Sure. it's the return value of a function, but that is entirely > useless and pointless information, and adds no value. We should name > variables by the data they contain or how they are used, not by "it > was the return value of a function"). > > In other words, why isn't this just > > if (__radix_tree_preload(..)) > preempt_disable(); > > which is shorter and clearer and not confusing? ... > Same issue, but this time strengthened by an additional "why doesn't > this just use that idr_preload function then?" question.. > Yep, I will send a v2, thanks.
diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 3527eb364964..fac702039304 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -463,7 +463,7 @@ radix_tree_node_free(struct radix_tree_node *node) * To make use of this facility, the radix tree must be initialised without * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). */ -static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr) +static __must_check int __radix_tree_preload(gfp_t gfp_mask, unsigned nr) { struct radix_tree_preload *rtp; struct radix_tree_node *node; @@ -2104,7 +2104,10 @@ EXPORT_SYMBOL(radix_tree_tagged); */ void idr_preload(gfp_t gfp_mask) { - __radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE); + int ret = __radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE); + + if (ret) + preempt_disable(); } EXPORT_SYMBOL(idr_preload); @@ -2118,13 +2121,14 @@ EXPORT_SYMBOL(idr_preload); */ int ida_pre_get(struct ida *ida, gfp_t gfp) { - __radix_tree_preload(gfp, IDA_PRELOAD_SIZE); + int ret = __radix_tree_preload(gfp, IDA_PRELOAD_SIZE); /* * The IDA API has no preload_end() equivalent. Instead, * ida_get_new() can return -EAGAIN, prompting the caller * to return to the ida_pre_get() step. */ - preempt_enable(); + if (!ret) + preempt_enable(); if (!this_cpu_read(ida_bitmap)) { struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp);