linux-kernel - Re: [PATCH v2 1/4] lib/rhashtable: simplify bucket_table

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180622181654.evngae326rd5hr4n@linux-r8p5>
Date:   Fri, 22 Jun 2018 11:16:54 -0700
From:   Davidlohr Bueso <dave@...olabs.net>
To:     akpm@...ux-foundation.org, torvalds@...ux-foundation.org
Cc:     tgraf@...g.ch, herbert@...dor.apana.org.au,
        manfred@...orfullife.com, mhocko@...nel.org,
        guillaume.knispel@...ersonicimagine.com, linux-api@...r.kernel.org,
        linux-kernel@...r.kernel.org, Davidlohr Bueso <dbueso@...e.de>,
        neilb@...e.com
Subject: Re: [PATCH v2 1/4] lib/rhashtable: simplify bucket_table_alloc()

Cc'ing Neil.

On Fri, 22 Jun 2018, Davidlohr Bueso wrote:

>As of ce91f6ee5b3 (mm: kvmalloc does not fallback to vmalloc for incompatible gfp flag),
>we can simplify the caller and trust kvzalloc() to just do the right thing. For the
>case of the GFP_ATOMIC context, we can drop the __GFP_NORETRY flag for obvious reasons,
>and for the __GFP_NOWARN case, however, it is changed such that the caller passes the
>flag instead of making bucket_table_alloc() handle it.
>
>This slightly changes the gfp flags passed on to nested_table_alloc() as it will now
>also use GFP_ATOMIC | __GFP_NOWARN. However, I consider this a positive consequence
>as for the same reasons we want nowarn semantics in bucket_table_alloc().
>
>Signed-off-by: Davidlohr Bueso <dbueso@...e.de>
>---
>
>v2:
>- Changes based on Neil's concerns about keeping nowarn flag.
>- Better changelog.
>
>
>lib/rhashtable.c | 7 ++-----
>1 file changed, 2 insertions(+), 5 deletions(-)
>
>diff --git a/lib/rhashtable.c b/lib/rhashtable.c
>index 9427b5766134..083f871491a1 100644
>--- a/lib/rhashtable.c
>+++ b/lib/rhashtable.c
>@@ -175,10 +175,7 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
>	int i;
>
>	size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
>-	if (gfp != GFP_KERNEL)
>-		tbl = kzalloc(size, gfp | __GFP_NOWARN | __GFP_NORETRY);
>-	else
>-		tbl = kvzalloc(size, gfp);
>+	tbl = kvzalloc(size, gfp);
>
>	size = nbuckets;
>
>@@ -459,7 +456,7 @@ static int rhashtable_insert_rehash(struct rhashtable *ht,
>
>	err = -ENOMEM;
>
>-	new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC);
>+	new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC | __GFP_NOWARN);
>	if (new_tbl == NULL)
>		goto fail;
>
>-- 
>2.16.4
>