scsi: cxlflash: Remove port configuration assumptions
authorMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Wed, 12 Apr 2017 19:14:05 +0000 (14:14 -0500)
committerMartin K. Petersen <martin.petersen@oracle.com>
Fri, 14 Apr 2017 02:55:41 +0000 (22:55 -0400)
At present, the cxlflash driver only supports hardware with two FC ports. The
code was initially designed with this assumption and is dependent on having
two FC ports - adding more ports will break logic within the driver.

To mitigate this issue, remove the existing port assumptions and transition
the code to support more than two ports. As a side effect, clarify the
interpretation of the DK_CXLFLASH_ALL_PORTS_ACTIVE flag.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Documentation/powerpc/cxlflash.txt
drivers/scsi/cxlflash/common.h
drivers/scsi/cxlflash/lunmgt.c
drivers/scsi/cxlflash/main.c
drivers/scsi/cxlflash/sislite.h
drivers/scsi/cxlflash/superpipe.c
drivers/scsi/cxlflash/superpipe.h
drivers/scsi/cxlflash/vlun.c

index 6d9a2ed32cad2848ad9d5c5890444b461febb84b..66b4496d6619a41f36cefc577afbb85d2ca43cc6 100644 (file)
@@ -239,6 +239,11 @@ DK_CXLFLASH_USER_VIRTUAL
     resource handle that is provided is already referencing provisioned
     storage. This is reflected by the last LBA being a non-zero value.
 
+    When a LUN is accessible from more than one port, this ioctl will
+    return with the DK_CXLFLASH_ALL_PORTS_ACTIVE return flag set. This
+    provides the user with a hint that I/O can be retried in the event
+    of an I/O error as the LUN can be reached over multiple paths.
+
 DK_CXLFLASH_VLUN_RESIZE
 -----------------------
     This ioctl is responsible for resizing a previously created virtual
index 6a04867a0eec669c6feb718c8faf4e4527b0c8c0..ee23e81994c487d0b91eb38a1d8a218187a4eb04 100644 (file)
@@ -29,6 +29,10 @@ extern const struct file_operations cxlflash_cxl_fops;
 #define NUM_FC_PORTS   CXLFLASH_NUM_FC_PORTS   /* ports per AFU */
 #define MAX_FC_PORTS   CXLFLASH_MAX_FC_PORTS   /* ports per AFU */
 
+#define CHAN2PORTMASK(_x)      (1 << (_x))     /* channel to port mask */
+#define PORTMASK2CHAN(_x)      (ilog2((_x)))   /* port mask to channel */
+#define PORTNUM2CHAN(_x)       ((_x) - 1)      /* port number to channel */
+
 #define CXLFLASH_BLOCK_SIZE    4096    /* 4K blocks */
 #define CXLFLASH_MAX_XFER_SIZE 16777216        /* 16MB transfer */
 #define CXLFLASH_MAX_SECTORS   (CXLFLASH_MAX_XFER_SIZE/512)    /* SCSI wants
index 0efed177cc8bd31c9cc1a80c62fcafc70a3a19f5..4d232e271af60edad6316f15e8cc1689b2e807ed 100644 (file)
@@ -252,7 +252,7 @@ int cxlflash_manage_lun(struct scsi_device *sdev,
                 * in unpacked, AFU-friendly format, and hang LUN reference in
                 * the sdev.
                 */
-               lli->port_sel |= CHAN2PORT(chan);
+               lli->port_sel |= CHAN2PORTMASK(chan);
                lli->lun_id[chan] = lun_to_lunid(sdev->lun);
                sdev->hostdata = lli;
        } else if (flags & DK_CXLFLASH_MANAGE_LUN_DISABLE_SUPERPIPE) {
@@ -264,7 +264,7 @@ int cxlflash_manage_lun(struct scsi_device *sdev,
                         * tracking when no more references exist.
                         */
                        sdev->hostdata = NULL;
-                       lli->port_sel &= ~CHAN2PORT(chan);
+                       lli->port_sel &= ~CHAN2PORTMASK(chan);
                        if (lli->port_sel == 0U)
                                lli->in_table = false;
                }
index 3f9c8690af0d6be07fdb746fe34a09960070b359..04e1a8effa76d1765d79340b04f58655b5e138d5 100644 (file)
@@ -365,7 +365,6 @@ static int wait_resp(struct afu *afu, struct afu_cmd *cmd)
  */
 static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd)
 {
-       u32 port_sel = scp->device->channel + 1;
        struct cxlflash_cfg *cfg = shost_priv(scp->device->host);
        struct afu_cmd *cmd = sc_to_afucz(scp);
        struct device *dev = &cfg->dev->dev;
@@ -388,7 +387,7 @@ static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd)
 
        cmd->rcb.ctx_id = afu->ctx_hndl;
        cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;
-       cmd->rcb.port_sel = port_sel;
+       cmd->rcb.port_sel = CHAN2PORTMASK(scp->device->channel);
        cmd->rcb.lun_id = lun_to_lunid(scp->device->lun);
        cmd->rcb.req_flags = (SISL_REQ_FLAGS_PORT_LUN_ID |
                              SISL_REQ_FLAGS_SUP_UNDERRUN |
@@ -444,7 +443,6 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp)
        struct device *dev = &cfg->dev->dev;
        struct afu_cmd *cmd = sc_to_afucz(scp);
        struct scatterlist *sg = scsi_sglist(scp);
-       u32 port_sel = scp->device->channel + 1;
        u16 req_flags = SISL_REQ_FLAGS_SUP_UNDERRUN;
        ulong lock_flags;
        int nseg = 0;
@@ -503,7 +501,7 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp)
 
        cmd->rcb.ctx_id = afu->ctx_hndl;
        cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;
-       cmd->rcb.port_sel = port_sel;
+       cmd->rcb.port_sel = CHAN2PORTMASK(scp->device->channel);
        cmd->rcb.lun_id = lun_to_lunid(scp->device->lun);
 
        if (scp->sc_data_direction == DMA_TO_DEVICE)
@@ -1558,7 +1556,8 @@ static int init_global(struct cxlflash_cfg *cfg)
                writeq_be(PORT0, &afu->afu_map->global.regs.afu_port_sel);
                num_ports = 0;
        } else {
-               writeq_be(BOTH_PORTS, &afu->afu_map->global.regs.afu_port_sel);
+               writeq_be(PORT_MASK(cfg->num_fc_ports),
+                         &afu->afu_map->global.regs.afu_port_sel);
                num_ports = cfg->num_fc_ports;
        }
 
@@ -2190,7 +2189,7 @@ static ssize_t lun_mode_store(struct device *dev,
                if (afu->internal_lun)
                        shost->max_channel = 0;
                else
-                       shost->max_channel = cfg->num_fc_ports - 1;
+                       shost->max_channel = PORTNUM2CHAN(cfg->num_fc_ports);
 
                afu_reset(cfg);
                scsi_scan_host(cfg->host);
@@ -2529,7 +2528,7 @@ static int cxlflash_probe(struct pci_dev *pdev,
 
        host->max_id = CXLFLASH_MAX_NUM_TARGETS_PER_BUS;
        host->max_lun = CXLFLASH_MAX_NUM_LUNS_PER_TARGET;
-       host->max_channel = NUM_FC_PORTS - 1;
+       host->max_channel = PORTNUM2CHAN(NUM_FC_PORTS);
        host->unique_id = host->host_no;
        host->max_cmd_len = CXLFLASH_MAX_CDB_LEN;
 
index 0db4bc1f4e2303ce0606a652fd0720087a6476e0..f26f41be5efb88b607fc70db83df0cf8c19bb7be 100644 (file)
@@ -479,7 +479,7 @@ struct sisl_rht_entry_f1 {
 
 #define PORT0  0x01U
 #define PORT1  0x02U
-#define BOTH_PORTS    (PORT0 | PORT1)
+#define PORT_MASK(_n)  ((1 << (_n)) - 1)
 
 /* AFU Sync Mode byte */
 #define AFU_LW_SYNC 0x0U
index b46fd2f4562857f83db851670c966e73853e3ac9..f3997bed88f49e79186ceaaccf1d6002ff2213f1 100644 (file)
@@ -1933,7 +1933,7 @@ static int cxlflash_disk_direct_open(struct scsi_device *sdev, void *arg)
        u64 lun_size = 0;
        u64 last_lba = 0;
        u64 rsrc_handle = -1;
-       u32 port = CHAN2PORT(sdev->channel);
+       u32 port = CHAN2PORTMASK(sdev->channel);
 
        int rc = 0;
 
index 690ce9c652b202e23bfeafc96fab48b9a7861b6a..8269ff854bbebd35f404961f297027153d03bf87 100644 (file)
@@ -33,9 +33,6 @@ extern struct cxlflash_global global;
 
 #define MAX_SECTOR_UNIT  512 /* max_sector is in 512 byte multiples */
 
-#define CHAN2PORT(_x)  ((_x) + 1)
-#define PORT2CHAN(_x)  ((_x) - 1)
-
 enum lun_mode {
        MODE_NONE = 0,
        MODE_VIRTUAL,
index 7aa06ef229fd7993761e19040b4feed6c628043d..067605b80fcde111f45ead600076c97e7fa3f694 100644 (file)
@@ -819,8 +819,8 @@ int cxlflash_vlun_resize(struct scsi_device *sdev,
 void cxlflash_restore_luntable(struct cxlflash_cfg *cfg)
 {
        struct llun_info *lli, *temp;
-       u32 chan;
        u32 lind;
+       int k;
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct sisl_global_map __iomem *agm = &afu->afu_map->global;
@@ -832,33 +832,41 @@ void cxlflash_restore_luntable(struct cxlflash_cfg *cfg)
                        continue;
 
                lind = lli->lun_index;
+               dev_dbg(dev, "%s: Virtual LUNs on slot %d:\n", __func__, lind);
 
-               if (lli->port_sel == BOTH_PORTS) {
-                       writeq_be(lli->lun_id[0], &agm->fc_port[0][lind]);
-                       writeq_be(lli->lun_id[1], &agm->fc_port[1][lind]);
-                       dev_dbg(dev, "%s: Virtual LUN on slot %d  id0=%llx "
-                               "id1=%llx\n", __func__, lind,
-                               lli->lun_id[0], lli->lun_id[1]);
-               } else {
-                       chan = PORT2CHAN(lli->port_sel);
-                       writeq_be(lli->lun_id[chan], &agm->fc_port[chan][lind]);
-                       dev_dbg(dev, "%s: Virtual LUN on slot %d chan=%d "
-                               "id=%llx\n", __func__, lind, chan,
-                               lli->lun_id[chan]);
-               }
+               for (k = 0; k < cfg->num_fc_ports; k++)
+                       if (lli->port_sel & (1 << k)) {
+                               writeq_be(lli->lun_id[k],
+                                         &agm->fc_port[k][lind]);
+                               dev_dbg(dev, "\t%d=%llx\n", k, lli->lun_id[k]);
+                       }
        }
 
        mutex_unlock(&global.mutex);
 }
 
+/**
+ * get_num_ports() - compute number of ports from port selection mask
+ * @psm:       Port selection mask.
+ *
+ * Return: Population count of port selection mask
+ */
+static inline u8 get_num_ports(u32 psm)
+{
+       static const u8 bits[16] = { 0, 1, 1, 2, 1, 2, 2, 3,
+                                    1, 2, 2, 3, 2, 3, 3, 4 };
+
+       return bits[psm & 0xf];
+}
+
 /**
  * init_luntable() - write an entry in the LUN table
  * @cfg:       Internal structure associated with the host.
  * @lli:       Per adapter LUN information structure.
  *
- * On successful return, a LUN table entry is created.
- * At the top for LUNs visible on both ports.
- * At the bottom for LUNs visible only on one port.
+ * On successful return, a LUN table entry is created:
+ *     - at the top for LUNs visible on multiple ports.
+ *     - at the bottom for LUNs visible only on one port.
  *
  * Return: 0 on success, -errno on failure
  */
@@ -866,7 +874,9 @@ static int init_luntable(struct cxlflash_cfg *cfg, struct llun_info *lli)
 {
        u32 chan;
        u32 lind;
+       u32 nports;
        int rc = 0;
+       int k;
        struct afu *afu = cfg->afu;
        struct device *dev = &cfg->dev->dev;
        struct sisl_global_map __iomem *agm = &afu->afu_map->global;
@@ -876,29 +886,46 @@ static int init_luntable(struct cxlflash_cfg *cfg, struct llun_info *lli)
        if (lli->in_table)
                goto out;
 
-       if (lli->port_sel == BOTH_PORTS) {
+       nports = get_num_ports(lli->port_sel);
+       if (nports == 0 || nports > cfg->num_fc_ports) {
+               WARN(1, "Unsupported port configuration nports=%u", nports);
+               rc = -EIO;
+               goto out;
+       }
+
+       if (nports > 1) {
                /*
-                * If this LUN is visible from both ports, we will put
+                * When LUN is visible from multiple ports, we will put
                 * it in the top half of the LUN table.
                 */
-               if ((cfg->promote_lun_index == cfg->last_lun_index[0]) ||
-                   (cfg->promote_lun_index == cfg->last_lun_index[1])) {
-                       rc = -ENOSPC;
-                       goto out;
+               for (k = 0; k < cfg->num_fc_ports; k++) {
+                       if (!(lli->port_sel & (1 << k)))
+                               continue;
+
+                       if (cfg->promote_lun_index == cfg->last_lun_index[k]) {
+                               rc = -ENOSPC;
+                               goto out;
+                       }
                }
 
                lind = lli->lun_index = cfg->promote_lun_index;
-               writeq_be(lli->lun_id[0], &agm->fc_port[0][lind]);
-               writeq_be(lli->lun_id[1], &agm->fc_port[1][lind]);
+               dev_dbg(dev, "%s: Virtual LUNs on slot %d:\n", __func__, lind);
+
+               for (k = 0; k < cfg->num_fc_ports; k++) {
+                       if (!(lli->port_sel & (1 << k)))
+                               continue;
+
+                       writeq_be(lli->lun_id[k], &agm->fc_port[k][lind]);
+                       dev_dbg(dev, "\t%d=%llx\n", k, lli->lun_id[k]);
+               }
+
                cfg->promote_lun_index++;
-               dev_dbg(dev, "%s: Virtual LUN on slot %d  id0=%llx id1=%llx\n",
-                       __func__, lind, lli->lun_id[0], lli->lun_id[1]);
        } else {
                /*
-                * If this LUN is visible only from one port, we will put
+                * When LUN is visible only from one port, we will put
                 * it in the bottom half of the LUN table.
                 */
-               chan = PORT2CHAN(lli->port_sel);
+               chan = PORTMASK2CHAN(lli->port_sel);
                if (cfg->promote_lun_index == cfg->last_lun_index[chan]) {
                        rc = -ENOSPC;
                        goto out;
@@ -907,7 +934,7 @@ static int init_luntable(struct cxlflash_cfg *cfg, struct llun_info *lli)
                lind = lli->lun_index = cfg->last_lun_index[chan];
                writeq_be(lli->lun_id[chan], &agm->fc_port[chan][lind]);
                cfg->last_lun_index[chan]--;
-               dev_dbg(dev, "%s: Virtual LUN on slot %d  chan=%d id=%llx\n",
+               dev_dbg(dev, "%s: Virtual LUNs on slot %d:\n\t%d=%llx\n",
                        __func__, lind, chan, lli->lun_id[chan]);
        }
 
@@ -1016,7 +1043,7 @@ int cxlflash_disk_virtual_open(struct scsi_device *sdev, void *arg)
        virt->last_lba = last_lba;
        virt->rsrc_handle = rsrc_handle;
 
-       if (lli->port_sel == BOTH_PORTS)
+       if (get_num_ports(lli->port_sel) > 1)
                virt->hdr.return_flags |= DK_CXLFLASH_ALL_PORTS_ACTIVE;
 out:
        if (likely(ctxi))