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authorMichal Hocko <mhocko@suse.com>2021-11-05 13:39:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 13:30:37 -0700
commitb7d90e7a5ea8d64e668d5685925900d33d3884d5 (patch)
treec8b3170c756e83bd1e9a5f28a0eed3dc7f0acb23 /mm/vmalloc.c
parent3252b1d8309ea42bc6329d9341072ecf1c9505c0 (diff)
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@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Neil Brown <neilb@suse.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: Uladzislau Rezki <urezki@gmail.com> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jeff Layton <jlayton@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmalloc.c')
-rw-r--r--mm/vmalloc.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 75fa100f5424..c56720136c45 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2983,8 +2983,16 @@ 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
*/