The patch titled
Subject: mm/vmalloc: be more explicit about supported gfp flags
has been added to the -mm tree. Its filename is
mm-vmalloc-be-more-explicit-about-supported-gfp-flags.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-vmalloc-be-more-explicit-about-supported-gfp-flags.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmalloc-be-more-explicit-about-supported-gfp-flags.patch
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------------------------------------------------------
From: Michal Hocko <mhocko@xxxxxxxx>
Subject: mm/vmalloc: be more explicit about supported gfp flags
The core of the vmalloc allocator __vmalloc_area_node doesn't say anything
about gfp mask argument. Not all gfp flags are supported though. Be more
explicit about constraints.
Link: https://lkml.kernel.org/r/20211020082545.4830-1-mhocko@xxxxxxxxxx
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Neil Brown <neilb@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Uladzislau Rezki <urezki@xxxxxxxxx>
Cc: Ilya Dryomov <idryomov@xxxxxxxxx>
Cc: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
--- a/mm/vmalloc.c~mm-vmalloc-be-more-explicit-about-supported-gfp-flags
+++ a/mm/vmalloc.c
@@ -2990,8 +2990,16 @@ fail:
* @caller: caller's return address
*
* Allocate enough pages to cover @size from the page level
- * allocator with @gfp_mask flags. Map them into contiguous
- * kernel virtual space, using a pagetable protection of @prot.
+ * allocator with @gfp_mask flags. Please note that the full set of gfp
+ * flags are not supported. GFP_KERNEL would be a preferred allocation mode
+ * but GFP_NOFS and GFP_NOIO are supported as well. Zone modifiers are not
+ * supported. From the reclaim modifiers__GFP_DIRECT_RECLAIM is required (aka
+ * GFP_NOWAIT is not supported) and only __GFP_NOFAIL is supported (aka
+ * __GFP_NORETRY and __GFP_RETRY_MAYFAIL are not supported).
+ * __GFP_NOWARN can be used to suppress error messages about failures.
+ *
+ * Map them into contiguous kernel virtual space, using a pagetable
+ * protection of @prot.
*
* Return: the address of the area or %NULL on failure
*/
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
mm-vmalloc-be-more-explicit-about-supported-gfp-flags.patch
