From f36afb3957353d2529cb2b00f78fdccd14fc5e9c Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 31 Oct 2013 13:55:45 -0400 Subject: [PATCH] dm: allocate buffer for messages with small number of arguments using GFP_NOIO dm-mpath and dm-thin must process messages even if some device is suspended, so we allocate argv buffer with GFP_NOIO. These messages have a small fixed number of arguments. On the other hand, dm-switch needs to process bulk data using messages so excessive use of GFP_NOIO could cause trouble. The patch also lowers the default number of arguments from 64 to 8, so that there is smaller load on GFP_NOIO allocations. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Acked-by: Alasdair G Kergon Signed-off-by: Mike Snitzer --- drivers/md/dm-table.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 8f8783533ac7..41d907b58f7e 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -545,14 +545,28 @@ static int adjoin(struct dm_table *table, struct dm_target *ti) /* * Used to dynamically allocate the arg array. + * + * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must + * process messages even if some device is suspended. These messages have a + * small fixed number of arguments. + * + * On the other hand, dm-switch needs to process bulk data using messages and + * excessive use of GFP_NOIO could cause trouble. */ static char **realloc_argv(unsigned *array_size, char **old_argv) { char **argv; unsigned new_size; + gfp_t gfp; - new_size = *array_size ? *array_size * 2 : 64; - argv = kmalloc(new_size * sizeof(*argv), GFP_KERNEL); + if (*array_size) { + new_size = *array_size * 2; + gfp = GFP_KERNEL; + } else { + new_size = 8; + gfp = GFP_NOIO; + } + argv = kmalloc(new_size * sizeof(*argv), gfp); if (argv) { memcpy(argv, old_argv, *array_size * sizeof(*argv)); *array_size = new_size;