IB/iser: set block queue_virt_boundary
authorSagi Grimberg <sagig@mellanox.com>
Tue, 13 Oct 2015 16:12:58 +0000 (19:12 +0300)
committerDoug Ledford <dledford@redhat.com>
Wed, 28 Oct 2015 16:26:06 +0000 (12:26 -0400)
The block layer can reliably guarantee that SG lists won't
contain gaps (page unaligned) if a driver set the queue
virt_boundary.

With this setting the block layer will:
- refuse merges if bios are not aligned to the virtual boundary
- split bios/requests that are not aligned to the virtual boundary
- or, bounce buffer SG_IOs that are not aligned to the virtual boundary

Since iser is working in 4K page size, set the virt_boundary to
4K pages. With this setting, we can now safely remove the bounce
buffering logic in iser.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>
drivers/infiniband/ulp/iser/iscsi_iser.c
drivers/infiniband/ulp/iser/iscsi_iser.h
drivers/infiniband/ulp/iser/iser_initiator.c
drivers/infiniband/ulp/iser/iser_memory.c

index 3d0bdb87a6531a276b7719b757788b96f7e3bae1..2ea0a14125e872316b7573bff50787d090f642e0 100644 (file)
@@ -762,9 +762,7 @@ iscsi_iser_conn_get_stats(struct iscsi_cls_conn *cls_conn, struct iscsi_stats *s
        stats->r2t_pdus = conn->r2t_pdus_cnt; /* always 0 */
        stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
        stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
-       stats->custom_length = 1;
-       strcpy(stats->custom[0].desc, "fmr_unalign_cnt");
-       stats->custom[0].value = conn->fmr_unalign_cnt;
+       stats->custom_length = 0;
 }
 
 static int iscsi_iser_get_ep_param(struct iscsi_endpoint *ep,
@@ -969,6 +967,13 @@ static umode_t iser_attr_is_visible(int param_type, int param)
        return 0;
 }
 
+static int iscsi_iser_slave_alloc(struct scsi_device *sdev)
+{
+       blk_queue_virt_boundary(sdev->request_queue, ~MASK_4K);
+
+       return 0;
+}
+
 static struct scsi_host_template iscsi_iser_sht = {
        .module                 = THIS_MODULE,
        .name                   = "iSCSI Initiator over iSER",
@@ -982,6 +987,7 @@ static struct scsi_host_template iscsi_iser_sht = {
        .eh_target_reset_handler = iscsi_eh_recover_target,
        .target_alloc           = iscsi_target_alloc,
        .use_clustering         = DISABLE_CLUSTERING,
+       .slave_alloc            = iscsi_iser_slave_alloc,
        .proc_name              = "iscsi_iser",
        .this_id                = -1,
        .track_queue_depth      = 1,
index a5edd6ede692c7be3d1c6da2f355b062cea9e43e..d8bbad9eb59b07d8249cf01d2c6e1ea42e843560 100644 (file)
@@ -227,18 +227,13 @@ enum iser_data_dir {
  * @size:         num entries of this sg
  * @data_len:     total beffer byte len
  * @dma_nents:    returned by dma_map_sg
- * @orig_sg:      pointer to the original sg list (in case
- *                we used a copy)
- * @orig_size:    num entris of orig sg list
  */
 struct iser_data_buf {
        struct scatterlist *sg;
        unsigned int       size;
        unsigned long      data_len;
        unsigned int       dma_nents;
-       struct scatterlist *orig_sg;
-       unsigned int       orig_size;
-  };
+};
 
 /* fwd declarations */
 struct iser_device;
index d511879d8cdfc862765f871b0876b43307e3b7c7..ffd00c42072959ed6747b5094e159cb34532675f 100644 (file)
@@ -661,48 +661,14 @@ void iser_task_rdma_init(struct iscsi_iser_task *iser_task)
 
 void iser_task_rdma_finalize(struct iscsi_iser_task *iser_task)
 {
-       int is_rdma_data_aligned = 1;
-       int is_rdma_prot_aligned = 1;
        int prot_count = scsi_prot_sg_count(iser_task->sc);
 
-       /* if we were reading, copy back to unaligned sglist,
-        * anyway dma_unmap and free the copy
-        */
-       if (iser_task->data[ISER_DIR_IN].orig_sg) {
-               is_rdma_data_aligned = 0;
-               iser_finalize_rdma_unaligned_sg(iser_task,
-                                               &iser_task->data[ISER_DIR_IN],
-                                               ISER_DIR_IN);
-       }
-
-       if (iser_task->data[ISER_DIR_OUT].orig_sg) {
-               is_rdma_data_aligned = 0;
-               iser_finalize_rdma_unaligned_sg(iser_task,
-                                               &iser_task->data[ISER_DIR_OUT],
-                                               ISER_DIR_OUT);
-       }
-
-       if (iser_task->prot[ISER_DIR_IN].orig_sg) {
-               is_rdma_prot_aligned = 0;
-               iser_finalize_rdma_unaligned_sg(iser_task,
-                                               &iser_task->prot[ISER_DIR_IN],
-                                               ISER_DIR_IN);
-       }
-
-       if (iser_task->prot[ISER_DIR_OUT].orig_sg) {
-               is_rdma_prot_aligned = 0;
-               iser_finalize_rdma_unaligned_sg(iser_task,
-                                               &iser_task->prot[ISER_DIR_OUT],
-                                               ISER_DIR_OUT);
-       }
-
        if (iser_task->dir[ISER_DIR_IN]) {
                iser_unreg_rdma_mem(iser_task, ISER_DIR_IN);
-               if (is_rdma_data_aligned)
-                       iser_dma_unmap_task_data(iser_task,
-                                                &iser_task->data[ISER_DIR_IN],
-                                                DMA_FROM_DEVICE);
-               if (prot_count && is_rdma_prot_aligned)
+               iser_dma_unmap_task_data(iser_task,
+                                        &iser_task->data[ISER_DIR_IN],
+                                        DMA_FROM_DEVICE);
+               if (prot_count)
                        iser_dma_unmap_task_data(iser_task,
                                                 &iser_task->prot[ISER_DIR_IN],
                                                 DMA_FROM_DEVICE);
@@ -710,11 +676,10 @@ void iser_task_rdma_finalize(struct iscsi_iser_task *iser_task)
 
        if (iser_task->dir[ISER_DIR_OUT]) {
                iser_unreg_rdma_mem(iser_task, ISER_DIR_OUT);
-               if (is_rdma_data_aligned)
-                       iser_dma_unmap_task_data(iser_task,
-                                                &iser_task->data[ISER_DIR_OUT],
-                                                DMA_TO_DEVICE);
-               if (prot_count && is_rdma_prot_aligned)
+               iser_dma_unmap_task_data(iser_task,
+                                        &iser_task->data[ISER_DIR_OUT],
+                                        DMA_TO_DEVICE);
+               if (prot_count)
                        iser_dma_unmap_task_data(iser_task,
                                                 &iser_task->prot[ISER_DIR_OUT],
                                                 DMA_TO_DEVICE);
index 4c46d67d37a13100b60c6daa0a0b01b8f6855608..3e0452c4248fffce0b8554014ae5ccc9051c6303 100644 (file)
@@ -88,113 +88,6 @@ int iser_assign_reg_ops(struct iser_device *device)
        return 0;
 }
 
-static void
-iser_free_bounce_sg(struct iser_data_buf *data)
-{
-       struct scatterlist *sg;
-       int count;
-
-       for_each_sg(data->sg, sg, data->size, count)
-               __free_page(sg_page(sg));
-
-       kfree(data->sg);
-
-       data->sg = data->orig_sg;
-       data->size = data->orig_size;
-       data->orig_sg = NULL;
-       data->orig_size = 0;
-}
-
-static int
-iser_alloc_bounce_sg(struct iser_data_buf *data)
-{
-       struct scatterlist *sg;
-       struct page *page;
-       unsigned long length = data->data_len;
-       int i = 0, nents = DIV_ROUND_UP(length, PAGE_SIZE);
-
-       sg = kcalloc(nents, sizeof(*sg), GFP_ATOMIC);
-       if (!sg)
-               goto err;
-
-       sg_init_table(sg, nents);
-       while (length) {
-               u32 page_len = min_t(u32, length, PAGE_SIZE);
-
-               page = alloc_page(GFP_ATOMIC);
-               if (!page)
-                       goto err;
-
-               sg_set_page(&sg[i], page, page_len, 0);
-               length -= page_len;
-               i++;
-       }
-
-       data->orig_sg = data->sg;
-       data->orig_size = data->size;
-       data->sg = sg;
-       data->size = nents;
-
-       return 0;
-
-err:
-       for (; i > 0; i--)
-               __free_page(sg_page(&sg[i - 1]));
-       kfree(sg);
-
-       return -ENOMEM;
-}
-
-static void
-iser_copy_bounce(struct iser_data_buf *data, bool to_buffer)
-{
-       struct scatterlist *osg, *bsg = data->sg;
-       void *oaddr, *baddr;
-       unsigned int left = data->data_len;
-       unsigned int bsg_off = 0;
-       int i;
-
-       for_each_sg(data->orig_sg, osg, data->orig_size, i) {
-               unsigned int copy_len, osg_off = 0;
-
-               oaddr = kmap_atomic(sg_page(osg)) + osg->offset;
-               copy_len = min(left, osg->length);
-               while (copy_len) {
-                       unsigned int len = min(copy_len, bsg->length - bsg_off);
-
-                       baddr = kmap_atomic(sg_page(bsg)) + bsg->offset;
-                       if (to_buffer)
-                               memcpy(baddr + bsg_off, oaddr + osg_off, len);
-                       else
-                               memcpy(oaddr + osg_off, baddr + bsg_off, len);
-
-                       kunmap_atomic(baddr - bsg->offset);
-                       osg_off += len;
-                       bsg_off += len;
-                       copy_len -= len;
-
-                       if (bsg_off >= bsg->length) {
-                               bsg = sg_next(bsg);
-                               bsg_off = 0;
-                       }
-               }
-               kunmap_atomic(oaddr - osg->offset);
-               left -= osg_off;
-       }
-}
-
-static inline void
-iser_copy_from_bounce(struct iser_data_buf *data)
-{
-       iser_copy_bounce(data, false);
-}
-
-static inline void
-iser_copy_to_bounce(struct iser_data_buf *data)
-{
-       iser_copy_bounce(data, true);
-}
-
 struct iser_fr_desc *
 iser_reg_desc_get_fr(struct ib_conn *ib_conn)
 {
@@ -238,62 +131,6 @@ iser_reg_desc_put_fmr(struct ib_conn *ib_conn,
 {
 }
 
-/**
- * iser_start_rdma_unaligned_sg
- */
-static int iser_start_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
-                                       struct iser_data_buf *data,
-                                       enum iser_data_dir cmd_dir)
-{
-       struct ib_device *dev = iser_task->iser_conn->ib_conn.device->ib_device;
-       int rc;
-
-       rc = iser_alloc_bounce_sg(data);
-       if (rc) {
-               iser_err("Failed to allocate bounce for data len %lu\n",
-                        data->data_len);
-               return rc;
-       }
-
-       if (cmd_dir == ISER_DIR_OUT)
-               iser_copy_to_bounce(data);
-
-       data->dma_nents = ib_dma_map_sg(dev, data->sg, data->size,
-                                       (cmd_dir == ISER_DIR_OUT) ?
-                                       DMA_TO_DEVICE : DMA_FROM_DEVICE);
-       if (!data->dma_nents) {
-               iser_err("Got dma_nents %d, something went wrong...\n",
-                        data->dma_nents);
-               rc = -ENOMEM;
-               goto err;
-       }
-
-       return 0;
-err:
-       iser_free_bounce_sg(data);
-       return rc;
-}
-
-/**
- * iser_finalize_rdma_unaligned_sg
- */
-
-void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
-                                    struct iser_data_buf *data,
-                                    enum iser_data_dir cmd_dir)
-{
-       struct ib_device *dev = iser_task->iser_conn->ib_conn.device->ib_device;
-
-       ib_dma_unmap_sg(dev, data->sg, data->size,
-                       (cmd_dir == ISER_DIR_OUT) ?
-                       DMA_TO_DEVICE : DMA_FROM_DEVICE);
-
-       if (cmd_dir == ISER_DIR_IN)
-               iser_copy_from_bounce(data);
-
-       iser_free_bounce_sg(data);
-}
-
 #define IS_4K_ALIGNED(addr)    ((((unsigned long)addr) & ~MASK_4K) == 0)
 
 /**
@@ -355,64 +192,6 @@ static int iser_sg_to_page_vec(struct iser_data_buf *data,
        return cur_page;
 }
 
-
-/**
- * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
- * for RDMA sub-list of a scatter-gather list of memory buffers, and  returns
- * the number of entries which are aligned correctly. Supports the case where
- * consecutive SG elements are actually fragments of the same physcial page.
- */
-static int iser_data_buf_aligned_len(struct iser_data_buf *data,
-                                    struct ib_device *ibdev,
-                                    unsigned sg_tablesize)
-{
-       struct scatterlist *sg, *sgl, *next_sg = NULL;
-       u64 start_addr, end_addr;
-       int i, ret_len, start_check = 0;
-
-       if (data->dma_nents == 1)
-               return 1;
-
-       sgl = data->sg;
-       start_addr  = ib_sg_dma_address(ibdev, sgl);
-
-       if (unlikely(sgl[0].offset &&
-                    data->data_len >= sg_tablesize * PAGE_SIZE)) {
-               iser_dbg("can't register length %lx with offset %x "
-                        "fall to bounce buffer\n", data->data_len,
-                        sgl[0].offset);
-               return 0;
-       }
-
-       for_each_sg(sgl, sg, data->dma_nents, i) {
-               if (start_check && !IS_4K_ALIGNED(start_addr))
-                       break;
-
-               next_sg = sg_next(sg);
-               if (!next_sg)
-                       break;
-
-               end_addr    = start_addr + ib_sg_dma_len(ibdev, sg);
-               start_addr  = ib_sg_dma_address(ibdev, next_sg);
-
-               if (end_addr == start_addr) {
-                       start_check = 0;
-                       continue;
-               } else
-                       start_check = 1;
-
-               if (!IS_4K_ALIGNED(end_addr))
-                       break;
-       }
-       ret_len = (next_sg) ? i : i+1;
-
-       if (unlikely(ret_len != data->dma_nents))
-               iser_warn("rdma alignment violation (%d/%d aligned)\n",
-                         ret_len, data->dma_nents);
-
-       return ret_len;
-}
-
 static void iser_data_buf_dump(struct iser_data_buf *data,
                               struct ib_device *ibdev)
 {
@@ -483,31 +262,6 @@ iser_reg_dma(struct iser_device *device, struct iser_data_buf *mem,
        return 0;
 }
 
-static int fall_to_bounce_buf(struct iscsi_iser_task *iser_task,
-                             struct iser_data_buf *mem,
-                             enum iser_data_dir cmd_dir)
-{
-       struct iscsi_conn *iscsi_conn = iser_task->iser_conn->iscsi_conn;
-       struct iser_device *device = iser_task->iser_conn->ib_conn.device;
-
-       iscsi_conn->fmr_unalign_cnt++;
-
-       if (iser_debug_level > 0)
-               iser_data_buf_dump(mem, device->ib_device);
-
-       /* unmap the command data before accessing it */
-       iser_dma_unmap_task_data(iser_task, mem,
-                                (cmd_dir == ISER_DIR_OUT) ?
-                                DMA_TO_DEVICE : DMA_FROM_DEVICE);
-
-       /* allocate copy buf, if we are writing, copy the */
-       /* unaligned scatterlist, dma map the copy        */
-       if (iser_start_rdma_unaligned_sg(iser_task, mem, cmd_dir) != 0)
-               return -ENOMEM;
-
-       return 0;
-}
-
 /**
  * iser_reg_page_vec - Register physical memory
  *
@@ -779,26 +533,6 @@ static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
        return 0;
 }
 
-static int
-iser_handle_unaligned_buf(struct iscsi_iser_task *task,
-                         struct iser_data_buf *mem,
-                         enum iser_data_dir dir)
-{
-       struct iser_conn *iser_conn = task->iser_conn;
-       struct iser_device *device = iser_conn->ib_conn.device;
-       int err, aligned_len;
-
-       aligned_len = iser_data_buf_aligned_len(mem, device->ib_device,
-                                               iser_conn->scsi_sg_tablesize);
-       if (aligned_len != mem->dma_nents) {
-               err = fall_to_bounce_buf(task, mem, dir);
-               if (err)
-                       return err;
-       }
-
-       return 0;
-}
-
 static int
 iser_reg_prot_sg(struct iscsi_iser_task *task,
                 struct iser_data_buf *mem,
@@ -841,10 +575,6 @@ int iser_reg_rdma_mem(struct iscsi_iser_task *task,
        bool use_dma_key;
        int err;
 
-       err = iser_handle_unaligned_buf(task, mem, dir);
-       if (unlikely(err))
-               return err;
-
        use_dma_key = (mem->dma_nents == 1 && !iser_always_reg &&
                       scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL);
 
@@ -867,10 +597,6 @@ int iser_reg_rdma_mem(struct iscsi_iser_task *task,
 
                if (scsi_prot_sg_count(task->sc)) {
                        mem = &task->prot[dir];
-                       err = iser_handle_unaligned_buf(task, mem, dir);
-                       if (unlikely(err))
-                               goto err_reg;
-
                        err = iser_reg_prot_sg(task, mem, desc,
                                               use_dma_key, prot_reg);
                        if (unlikely(err))