| Message ID | 1542346829-31063-1-git-send-email-yamada.masahiro@socionext.com |
|---|---|
| State | New |
| Headers | show |
| Series | slab: fix 'dubious: x & !y' warning from Sparse | expand |
On Fri 16-11-18 14:40:29, Masahiro Yamada wrote: > Sparse reports: > ./include/linux/slab.h:332:43: warning: dubious: x & !y JFYI this has been discussed here http://lkml.kernel.org/r/20181105204000.129023-1-bvanassche@acm.org > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > > include/linux/slab.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/slab.h b/include/linux/slab.h > index 918f374..d395c73 100644 > --- a/include/linux/slab.h > +++ b/include/linux/slab.h > @@ -329,7 +329,7 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags) > * If an allocation is both __GFP_DMA and __GFP_RECLAIMABLE, return > * KMALLOC_DMA and effectively ignore __GFP_RECLAIMABLE > */ > - return type_dma + (is_reclaimable & !is_dma) * KMALLOC_RECLAIM; > + return type_dma + (is_reclaimable && !is_dma) * KMALLOC_RECLAIM; > } > > /* > -- > 2.7.4 -- Michal Hocko SUSE Labs
On Fri, 16 Nov 2018, Masahiro Yamada wrote: > diff --git a/include/linux/slab.h b/include/linux/slab.h > index 918f374..d395c73 100644 > --- a/include/linux/slab.h > +++ b/include/linux/slab.h > @@ -329,7 +329,7 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags) > * If an allocation is both __GFP_DMA and __GFP_RECLAIMABLE, return > * KMALLOC_DMA and effectively ignore __GFP_RECLAIMABLE > */ > - return type_dma + (is_reclaimable & !is_dma) * KMALLOC_RECLAIM; > + return type_dma + (is_reclaimable && !is_dma) * KMALLOC_RECLAIM; > } Ok then lets revert the initial patch whose point was to avoid a branch. && causes a branch again.
On Fri 16-11-18 13:51:19, Cristopher Lameter wrote: > On Fri, 16 Nov 2018, Masahiro Yamada wrote: > > > diff --git a/include/linux/slab.h b/include/linux/slab.h > > index 918f374..d395c73 100644 > > --- a/include/linux/slab.h > > +++ b/include/linux/slab.h > > @@ -329,7 +329,7 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags) > > * If an allocation is both __GFP_DMA and __GFP_RECLAIMABLE, return > > * KMALLOC_DMA and effectively ignore __GFP_RECLAIMABLE > > */ > > - return type_dma + (is_reclaimable & !is_dma) * KMALLOC_RECLAIM; > > + return type_dma + (is_reclaimable && !is_dma) * KMALLOC_RECLAIM; > > } > > Ok then lets revert the initial patch whose point was to avoid a branch. > && causes a branch again. I believe Vlastimil managed to get rid of the branch http://lkml.kernel.org/r/aa5975b6-58ed-5a3e-7de1-4b1384f88457@suse.cz -- Michal Hocko SUSE Labs
diff --git a/include/linux/slab.h b/include/linux/slab.h index 918f374..d395c73 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -329,7 +329,7 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags) * If an allocation is both __GFP_DMA and __GFP_RECLAIMABLE, return * KMALLOC_DMA and effectively ignore __GFP_RECLAIMABLE */ - return type_dma + (is_reclaimable & !is_dma) * KMALLOC_RECLAIM; + return type_dma + (is_reclaimable && !is_dma) * KMALLOC_RECLAIM; } /*
Sparse reports: ./include/linux/slab.h:332:43: warning: dubious: x & !y Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- include/linux/slab.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.7.4