[openib-general] [PATCH] IB/iser: do I/O path allocations with GFP_NOIO

[Or Gerlitz]

Thanks for Mike Christie for pointing this out - Or.

a block driver is not allowed to use GFP_KERNEL allocations on its I/O code
path since the allocation might require I/O (eg to pageout other memory),
resulting in either deadlock or tightloop.

move I/O path (queuecommand) allocations to be done with GFP_NOIO

Signed-off-by: Or Gerlitz <ogerlitz at voltaire.com>

diff --git a/drivers/infiniband/ulp/iser/iser_initiator.c b/drivers/infiniband/ulp/iser/iser_initiator.c
index 2703bb0..073e7b5 100644
--- a/drivers/infiniband/ulp/iser/iser_initiator.c
+++ b/drivers/infiniband/ulp/iser/iser_initiator.c
@@ -225,7 +225,7 @@ static int iser_post_receive_control(str
 	struct iser_device  *device = iser_conn->ib_conn->device;
 	int rx_data_size, err = 0;

-	rx_desc = kmem_cache_alloc(ig.desc_cache, GFP_KERNEL);
+	rx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
 	if (rx_desc == NULL) {
 		iser_err("Failed to alloc desc for post recv\n");
 		return -ENOMEM;
@@ -238,7 +238,7 @@ static int iser_post_receive_control(str
 	else /* FIXME till user space sets conn->max_recv_dlength correctly */
 		rx_data_size = 128;

-	rx_desc->data = kmalloc(rx_data_size, GFP_KERNEL);
+	rx_desc->data = kmalloc(rx_data_size, GFP_NOIO);
 	if (rx_desc->data == NULL) {
 		iser_err("Failed to alloc data buf for post recv\n");
 		err = -ENOMEM;
@@ -467,7 +467,7 @@ int iser_send_data_out(struct iscsi_conn
 	iser_dbg("%s itt %d dseg_len %d offset %d\n",
 		 __func__,(int)itt,(int)data_seg_len,(int)buf_offset);

-	tx_desc = kmem_cache_alloc(ig.desc_cache, GFP_KERNEL);
+	tx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
 	if (tx_desc == NULL) {
 		iser_err("Failed to alloc desc for post dataout\n");
 		return -ENOMEM;
diff --git a/drivers/infiniband/ulp/iser/iser_memory.c b/drivers/infiniband/ulp/iser/iser_memory.c
index 0881f55..31950a5 100644
--- a/drivers/infiniband/ulp/iser/iser_memory.c
+++ b/drivers/infiniband/ulp/iser/iser_memory.c
@@ -111,10 +111,10 @@ int iser_start_rdma_unaligned_sg(struct
 	unsigned long  cmd_data_len = data->data_len;

 	if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
-		mem = (void *)__get_free_pages(GFP_KERNEL,
+		mem = (void *)__get_free_pages(GFP_NOIO,
 		      long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
 	else
-		mem = kmalloc(cmd_data_len, GFP_KERNEL);
+		mem = kmalloc(cmd_data_len, GFP_NOIO);

 	if (mem == NULL) {
 		iser_err("Failed to allocate mem size %d %d for copying sglist\n",