Introduces Chain lookup table/tracker and implements accessing chain buffer
using smid.
Removed link list based access of chain buffer which requires lock and
allocated as many chains needed.

Signed-off-by: Chaitra P B <chaitra.basa...@broadcom.com>
Signed-off-by: Suganath Prabu S <suganath-prabu.subram...@broadcom.com>
---
 drivers/scsi/mpt3sas/mpt3sas_base.c | 111 +++++++++++++++++++-----------------
 drivers/scsi/mpt3sas/mpt3sas_base.h |   8 ++-
 2 files changed, 65 insertions(+), 54 deletions(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c 
b/drivers/scsi/mpt3sas/mpt3sas_base.c
index b23a2eb..438da7c 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -297,12 +297,15 @@ static void *
 _base_get_chain_buffer_dma_to_chain_buffer(struct MPT3SAS_ADAPTER *ioc,
                dma_addr_t chain_buffer_dma)
 {
-       u16 index;
-
-       for (index = 0; index < ioc->chain_depth; index++) {
-               if (ioc->chain_lookup[index].chain_buffer_dma ==
-                               chain_buffer_dma)
-                       return ioc->chain_lookup[index].chain_buffer;
+       u16 index, j;
+       struct chain_tracker *ct;
+
+       for (index = 0; index < ioc->scsiio_depth; index++) {
+               for (j = 0; j < ioc->chains_needed_per_io; j++) {
+                       ct = &ioc->chain_lookup[index].chains_per_smid[j];
+                       if (ct && ct->chain_buffer_dma == chain_buffer_dma)
+                               return ct->chain_buffer;
+               }
        }
        pr_info(MPT3SAS_FMT
            "Provided chain_buffer_dma address is not in the lookup list\n",
@@ -1679,7 +1682,8 @@ _base_add_sg_single_64(void *paddr, u32 flags_length, 
dma_addr_t dma_addr)
  * @ioc: per adapter object
  * @scmd: SCSI commands of the IO request
  *
- * Returns chain tracker(from ioc->free_chain_list)
+ * Returns chain tracker from chain_lookup table using key as
+ * smid and smid's chain_offset.
  */
 static struct chain_tracker *
 _base_get_chain_buffer_tracker(struct MPT3SAS_ADAPTER *ioc,
@@ -1687,20 +1691,15 @@ _base_get_chain_buffer_tracker(struct MPT3SAS_ADAPTER 
*ioc,
 {
        struct chain_tracker *chain_req;
        struct scsiio_tracker *st = scsi_cmd_priv(scmd);
-       unsigned long flags;
+       u16 smid = st->smid;
+       u8 chain_offset =
+          atomic_read(&ioc->chain_lookup[smid - 1].chain_offset);
 
-       spin_lock_irqsave(&ioc->scsi_lookup_lock, flags);
-       if (list_empty(&ioc->free_chain_list)) {
-               spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags);
-               dfailprintk(ioc, pr_warn(MPT3SAS_FMT
-                       "chain buffers not available\n", ioc->name));
+       if (chain_offset == ioc->chains_needed_per_io)
                return NULL;
-       }
-       chain_req = list_entry(ioc->free_chain_list.next,
-           struct chain_tracker, tracker_list);
-       list_del_init(&chain_req->tracker_list);
-       list_add_tail(&chain_req->tracker_list, &st->chain_list);
-       spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags);
+
+       chain_req = &ioc->chain_lookup[smid - 1].chains_per_smid[chain_offset];
+       atomic_inc(&ioc->chain_lookup[smid - 1].chain_offset);
        return chain_req;
 }
 
@@ -3278,13 +3277,7 @@ void mpt3sas_base_clear_st(struct MPT3SAS_ADAPTER *ioc,
                return;
        st->cb_idx = 0xFF;
        st->direct_io = 0;
-       if (!list_empty(&st->chain_list)) {
-               unsigned long flags;
-
-               spin_lock_irqsave(&ioc->scsi_lookup_lock, flags);
-               list_splice_init(&st->chain_list, &ioc->free_chain_list);
-               spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags);
-       }
+       atomic_set(&ioc->chain_lookup[st->smid - 1].chain_offset, 0);
 }
 
 /**
@@ -4102,6 +4095,8 @@ static void
 _base_release_memory_pools(struct MPT3SAS_ADAPTER *ioc)
 {
        int i = 0;
+       int j = 0;
+       struct chain_tracker *ct;
        struct reply_post_struct *rps;
 
        dexitprintk(ioc, pr_info(MPT3SAS_FMT "%s\n", ioc->name,
@@ -4192,14 +4187,18 @@ _base_release_memory_pools(struct MPT3SAS_ADAPTER *ioc)
        kfree(ioc->hpr_lookup);
        kfree(ioc->internal_lookup);
        if (ioc->chain_lookup) {
-               for (i = 0; i < ioc->chain_depth; i++) {
-                       if (ioc->chain_lookup[i].chain_buffer)
-                               dma_pool_free(ioc->chain_dma_pool,
-                                   ioc->chain_lookup[i].chain_buffer,
-                                   ioc->chain_lookup[i].chain_buffer_dma);
+               for (i = 0; i < ioc->scsiio_depth; i++) {
+                       for (j = 0; j < ioc->chains_needed_per_io; j++) {
+                               ct = &ioc->chain_lookup[i].chains_per_smid[j];
+                               if (ct && ct->chain_buffer)
+                                       dma_pool_free(ioc->chain_dma_pool,
+                                               ct->chain_buffer,
+                                               ct->chain_buffer_dma);
+                       }
+                       kfree(ioc->chain_lookup[i].chains_per_smid);
                }
                dma_pool_destroy(ioc->chain_dma_pool);
-               free_pages((ulong)ioc->chain_lookup, ioc->chain_pages);
+               kfree(ioc->chain_lookup);
                ioc->chain_lookup = NULL;
        }
 }
@@ -4221,7 +4220,8 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc)
        u16 max_request_credit, nvme_blocks_needed;
        unsigned short sg_tablesize;
        u16 sge_size;
-       int i;
+       int i, j;
+       struct chain_tracker *ct;
 
        dinitprintk(ioc, pr_info(MPT3SAS_FMT "%s\n", ioc->name,
            __func__));
@@ -4502,15 +4502,24 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc)
                ioc->name, ioc->request, ioc->scsiio_depth));
 
        ioc->chain_depth = min_t(u32, ioc->chain_depth, MAX_CHAIN_DEPTH);
-       sz = ioc->chain_depth * sizeof(struct chain_tracker);
-       ioc->chain_pages = get_order(sz);
-       ioc->chain_lookup = (struct chain_tracker *)__get_free_pages(
-           GFP_KERNEL, ioc->chain_pages);
+       sz = ioc->scsiio_depth * sizeof(struct chain_lookup);
+       ioc->chain_lookup = kzalloc(sz, GFP_KERNEL);
        if (!ioc->chain_lookup) {
-               pr_err(MPT3SAS_FMT "chain_lookup: __get_free_pages failed\n",
-                       ioc->name);
+               pr_err(MPT3SAS_FMT "chain_lookup: __get_free_pages "
+               "failed\n", ioc->name);
                goto out;
        }
+
+       sz = ioc->chains_needed_per_io * sizeof(struct chain_tracker);
+       for (i = 0; i < ioc->scsiio_depth; i++) {
+               ioc->chain_lookup[i].chains_per_smid = kzalloc(sz, GFP_KERNEL);
+               if (!ioc->chain_lookup[i].chains_per_smid) {
+                       pr_err(MPT3SAS_FMT "chain_lookup: "
+                                       " kzalloc failed\n", ioc->name);
+                       goto out;
+               }
+       }
+
        ioc->chain_dma_pool = dma_pool_create("chain pool", &ioc->pdev->dev,
            ioc->chain_segment_sz, 16, 0);
        if (!ioc->chain_dma_pool) {
@@ -4518,17 +4527,21 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc)
                        ioc->name);
                goto out;
        }
-       for (i = 0; i < ioc->chain_depth; i++) {
-               ioc->chain_lookup[i].chain_buffer = dma_pool_alloc(
+       for (i = 0; i < ioc->scsiio_depth; i++) {
+               for (j = 0; j < ioc->chains_needed_per_io; j++) {
+                       ct = &ioc->chain_lookup[i].chains_per_smid[j];
+                       ct->chain_buffer = dma_pool_alloc(
                    ioc->chain_dma_pool , GFP_KERNEL,
-                   &ioc->chain_lookup[i].chain_buffer_dma);
-               if (!ioc->chain_lookup[i].chain_buffer) {
-                       ioc->chain_depth = i;
-                       goto chain_done;
+                   &ct->chain_buffer_dma);
+                       if (!ct->chain_buffer) {
+                               pr_err(MPT3SAS_FMT "chain_lookup: "
+                               " pci_pool_alloc failed\n", ioc->name);
+                               goto out;
+                       }
                }
                total_sz += ioc->chain_segment_sz;
        }
- chain_done:
+
        dinitprintk(ioc, pr_info(MPT3SAS_FMT
                "chain pool depth(%d), frame_size(%d), pool_size(%d kB)\n",
                ioc->name, ioc->chain_depth, ioc->chain_segment_sz,
@@ -6176,12 +6189,6 @@ _base_make_ioc_operational(struct MPT3SAS_ADAPTER *ioc)
                    &ioc->internal_free_list);
        }
 
-       /* chain pool */
-       INIT_LIST_HEAD(&ioc->free_chain_list);
-       for (i = 0; i < ioc->chain_depth; i++)
-               list_add_tail(&ioc->chain_lookup[i].tracker_list,
-                   &ioc->free_chain_list);
-
        spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags);
 
        /* initialize Reply Free Queue */
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.h 
b/drivers/scsi/mpt3sas/mpt3sas_base.h
index f997aad..01eb910 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.h
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.h
@@ -770,7 +770,11 @@ struct pcie_sg_list {
 struct chain_tracker {
        void *chain_buffer;
        dma_addr_t chain_buffer_dma;
-       struct list_head tracker_list;
+};
+
+struct chain_lookup {
+       struct chain_tracker *chains_per_smid;
+       atomic_t        chain_offset;
 };
 
 /**
@@ -1261,7 +1265,7 @@ struct MPT3SAS_ADAPTER {
        u32             page_size;
 
        /* chain */
-       struct chain_tracker *chain_lookup;
+       struct chain_lookup *chain_lookup;
        struct list_head free_chain_list;
        struct dma_pool *chain_dma_pool;
        ulong           chain_pages;
-- 
1.8.3.1

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