alloc_vmap_area() currently assumes that sleeping is allowed during allocation. This is not true for callers which pass non-blocking GFP flags, such as GFP_ATOMIC or GFP_NOWAIT. This patch adds logic to detect whether the given gfp_mask permits blocking. It avoids invoking might_sleep() or falling back to reclaim path if blocking is not allowed. This makes alloc_vmap_area() safer for use in non-sleeping contexts, where previously it could hit unexpected sleeps, trigger warnings. It is a preparation and adjustment step to later allow both GFP_ATOMIC and GFP_NOWAIT allocations in this series. Acked-by: Michal Hocko Signed-off-by: Uladzislau Rezki (Sony) --- mm/vmalloc.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 5edd536ba9d2..49a0f81930a8 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2017,6 +2017,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, unsigned long freed; unsigned long addr; unsigned int vn_id; + bool allow_block; int purged = 0; int ret; @@ -2028,7 +2029,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, /* Only reclaim behaviour flags are relevant. */ gfp_mask = gfp_mask & GFP_RECLAIM_MASK; - might_sleep(); + allow_block = gfpflags_allow_blocking(gfp_mask); + might_sleep_if(allow_block); /* * If a VA is obtained from a global heap(if it fails here) @@ -2065,8 +2067,16 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, * If an allocation fails, the error value is * returned. Therefore trigger the overflow path. */ - if (IS_ERR_VALUE(addr)) - goto overflow; + if (IS_ERR_VALUE(addr)) { + if (allow_block) + goto overflow; + + /* + * We can not trigger any reclaim logic because + * sleeping is not allowed, thus fail an allocation. + */ + goto out_free_va; + } va->va_start = addr; va->va_end = addr + size; @@ -2116,6 +2126,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, pr_warn("vmalloc_node_range for size %lu failed: Address range restricted to %#lx - %#lx\n", size, vstart, vend); +out_free_va: kmem_cache_free(vmap_area_cachep, va); return ERR_PTR(-EBUSY); } -- 2.47.3