[PATCH v3 07/17] dmaengine: bcm-sba-raid: Allow arbitrary number free sba_request

From: Anup Patel
Date: Tue Aug 22 2017 - 05:58:18 EST


Currently, we cannot have any arbitrary number of free sba_request
because sba_prealloc_channel_resources() allocates an array of
sba_request using devm_kcalloc() and kcalloc() cannot provide
memory beyond certain size.

This patch removes "reqs" (sba_request array) from sba_device
and makes "cmds" as variable array (instead of pointer) in
sba_request. This helps sba_prealloc_channel_resources() to
allocate sba_request and associated SBA command in one allocation
which in-turn allows arbitrary number of free sba_request.

Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxxxx>
---
drivers/dma/bcm-sba-raid.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/drivers/dma/bcm-sba-raid.c b/drivers/dma/bcm-sba-raid.c
index 59ef443..cd6e3cd 100644
--- a/drivers/dma/bcm-sba-raid.c
+++ b/drivers/dma/bcm-sba-raid.c
@@ -113,9 +113,10 @@ struct sba_request {
struct list_head next;
atomic_t next_pending_count;
/* BRCM message data */
- struct brcm_sba_command *cmds;
struct brcm_message msg;
struct dma_async_tx_descriptor tx;
+ /* SBA commands */
+ struct brcm_sba_command cmds[0];
};

enum sba_version {
@@ -153,7 +154,6 @@ struct sba_device {
void *cmds_base;
dma_addr_t cmds_dma_base;
spinlock_t reqs_lock;
- struct sba_request *reqs;
bool reqs_fence;
struct list_head reqs_alloc_list;
struct list_head reqs_pending_list;
@@ -1484,26 +1484,20 @@ static int sba_prealloc_channel_resources(struct sba_device *sba)
INIT_LIST_HEAD(&sba->reqs_aborted_list);
INIT_LIST_HEAD(&sba->reqs_free_list);

- sba->reqs = devm_kcalloc(sba->dev, sba->max_req,
- sizeof(*req), GFP_KERNEL);
- if (!sba->reqs) {
- ret = -ENOMEM;
- goto fail_free_cmds_pool;
- }
-
for (i = 0; i < sba->max_req; i++) {
- req = &sba->reqs[i];
+ req = devm_kzalloc(sba->dev,
+ sizeof(*req) +
+ sba->max_cmd_per_req * sizeof(req->cmds[0]),
+ GFP_KERNEL);
+ if (!req) {
+ ret = -ENOMEM;
+ goto fail_free_cmds_pool;
+ }
INIT_LIST_HEAD(&req->node);
req->sba = sba;
req->flags = SBA_REQUEST_STATE_FREE;
INIT_LIST_HEAD(&req->next);
atomic_set(&req->next_pending_count, 0);
- req->cmds = devm_kcalloc(sba->dev, sba->max_cmd_per_req,
- sizeof(*req->cmds), GFP_KERNEL);
- if (!req->cmds) {
- ret = -ENOMEM;
- goto fail_free_cmds_pool;
- }
for (j = 0; j < sba->max_cmd_per_req; j++) {
req->cmds[j].cmd = 0;
req->cmds[j].cmd_dma = sba->cmds_base +
--
2.7.4