net/ism: Add new API for client registration
authorStefan Raspl <raspl@linux.ibm.com>
Mon, 23 Jan 2023 18:17:48 +0000 (19:17 +0100)
committerDavid S. Miller <davem@davemloft.net>
Wed, 25 Jan 2023 09:46:48 +0000 (09:46 +0000)
Add a new API that allows other drivers to concurrently access ISM devices.
To do so, we introduce a new API that allows other modules to register for
ISM device usage. Furthermore, we move the GID to struct ism, where it
belongs conceptually, and rename and relocate struct smcd_event to struct
ism_event.
This is the first part of a bigger overhaul of the interfaces between SMC
and ISM.

Signed-off-by: Stefan Raspl <raspl@linux.ibm.com>
Signed-off-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/s390/net/ism.h
drivers/s390/net/ism_drv.c
include/linux/ism.h
include/net/smc.h
net/smc/smc_ism.c

index 90af513..70c5bbd 100644 (file)
@@ -16,7 +16,6 @@
  */
 #define ISM_DMB_WORD_OFFSET    1
 #define ISM_DMB_BIT_OFFSET     (ISM_DMB_WORD_OFFSET * 32)
-#define ISM_NR_DMBS            1920
 #define ISM_IDENT_MASK         0x00FFFF
 
 #define ISM_REG_SBA    0x1
@@ -178,7 +177,7 @@ struct ism_eq_header {
 
 struct ism_eq {
        struct ism_eq_header header;
-       struct smcd_event entry[15];
+       struct ism_event entry[15];
 };
 
 struct ism_sba {
@@ -190,21 +189,6 @@ struct ism_sba {
        u16 dmbe_mask[ISM_NR_DMBS];
 };
 
-struct ism_dev {
-       spinlock_t lock;
-       struct pci_dev *pdev;
-       struct smcd_dev *smcd;
-
-       struct ism_sba *sba;
-       dma_addr_t sba_dma_addr;
-       DECLARE_BITMAP(sba_bitmap, ISM_NR_DMBS);
-
-       struct ism_eq *ieq;
-       dma_addr_t ieq_dma_addr;
-
-       int ieq_idx;
-};
-
 #define ISM_CREATE_REQ(dmb, idx, sf, offset)           \
        ((dmb) | (idx) << 24 | (sf) << 23 | (offset))
 
index b9f33f4..2498322 100644 (file)
@@ -15,9 +15,6 @@
 #include <linux/err.h>
 #include <linux/ctype.h>
 #include <linux/processor.h>
-#include <net/smc.h>
-
-#include <asm/debug.h>
 
 #include "ism.h"
 
@@ -34,6 +31,84 @@ static const struct pci_device_id ism_device_table[] = {
 MODULE_DEVICE_TABLE(pci, ism_device_table);
 
 static debug_info_t *ism_debug_info;
+static const struct smcd_ops ism_ops;
+
+#define NO_CLIENT              0xff            /* must be >= MAX_CLIENTS */
+static struct ism_client *clients[MAX_CLIENTS];        /* use an array rather than */
+                                               /* a list for fast mapping  */
+static u8 max_client;
+static DEFINE_SPINLOCK(clients_lock);
+struct ism_dev_list {
+       struct list_head list;
+       struct mutex mutex; /* protects ism device list */
+};
+
+static struct ism_dev_list ism_dev_list = {
+       .list = LIST_HEAD_INIT(ism_dev_list.list),
+       .mutex = __MUTEX_INITIALIZER(ism_dev_list.mutex),
+};
+
+int ism_register_client(struct ism_client *client)
+{
+       struct ism_dev *ism;
+       unsigned long flags;
+       int i, rc = -ENOSPC;
+
+       mutex_lock(&ism_dev_list.mutex);
+       spin_lock_irqsave(&clients_lock, flags);
+       for (i = 0; i < MAX_CLIENTS; ++i) {
+               if (!clients[i]) {
+                       clients[i] = client;
+                       client->id = i;
+                       if (i == max_client)
+                               max_client++;
+                       rc = 0;
+                       break;
+               }
+       }
+       spin_unlock_irqrestore(&clients_lock, flags);
+       if (i < MAX_CLIENTS) {
+               /* initialize with all devices that we got so far */
+               list_for_each_entry(ism, &ism_dev_list.list, list) {
+                       ism->priv[i] = NULL;
+                       client->add(ism);
+               }
+       }
+       mutex_unlock(&ism_dev_list.mutex);
+
+       return rc;
+}
+EXPORT_SYMBOL_GPL(ism_register_client);
+
+int ism_unregister_client(struct ism_client *client)
+{
+       struct ism_dev *ism;
+       unsigned long flags;
+       int rc = 0;
+
+       mutex_lock(&ism_dev_list.mutex);
+       spin_lock_irqsave(&clients_lock, flags);
+       clients[client->id] = NULL;
+       if (client->id + 1 == max_client)
+               max_client--;
+       spin_unlock_irqrestore(&clients_lock, flags);
+       list_for_each_entry(ism, &ism_dev_list.list, list) {
+               for (int i = 0; i < ISM_NR_DMBS; ++i) {
+                       if (ism->sba_client_arr[i] == client->id) {
+                               pr_err("%s: attempt to unregister client '%s'"
+                                      "with registered dmb(s)\n", __func__,
+                                      client->name);
+                               rc = -EBUSY;
+                               goto out;
+                       }
+               }
+       }
+out:
+       mutex_unlock(&ism_dev_list.mutex);
+
+       return rc;
+}
+EXPORT_SYMBOL_GPL(ism_unregister_client);
 
 static int ism_cmd(struct ism_dev *ism, void *cmd)
 {
@@ -193,7 +268,7 @@ static int ism_read_local_gid(struct ism_dev *ism)
        if (ret)
                goto out;
 
-       ism->smcd->local_gid = cmd.response.gid;
+       ism->local_gid = cmd.response.gid;
 out:
        return ret;
 }
@@ -437,7 +512,8 @@ static u16 ism_get_chid(struct smcd_dev *smcd)
 
 static void ism_handle_event(struct ism_dev *ism)
 {
-       struct smcd_event *entry;
+       struct ism_event *entry;
+       int i;
 
        while ((ism->ieq_idx + 1) != READ_ONCE(ism->ieq->header.idx)) {
                if (++(ism->ieq_idx) == ARRAY_SIZE(ism->ieq->entry))
@@ -445,13 +521,18 @@ static void ism_handle_event(struct ism_dev *ism)
 
                entry = &ism->ieq->entry[ism->ieq_idx];
                debug_event(ism_debug_info, 2, entry, sizeof(*entry));
-               smcd_handle_event(ism->smcd, entry);
+               spin_lock(&clients_lock);
+               for (i = 0; i < max_client; ++i)
+                       if (clients[i])
+                               clients[i]->handle_event(ism, entry);
+               spin_unlock(&clients_lock);
        }
 }
 
 static irqreturn_t ism_handle_irq(int irq, void *data)
 {
        struct ism_dev *ism = data;
+       struct ism_client *clt;
        unsigned long bit, end;
        unsigned long *bv;
        u16 dmbemask;
@@ -471,7 +552,8 @@ static irqreturn_t ism_handle_irq(int irq, void *data)
                dmbemask = ism->sba->dmbe_mask[bit + ISM_DMB_BIT_OFFSET];
                ism->sba->dmbe_mask[bit + ISM_DMB_BIT_OFFSET] = 0;
                barrier();
-               smcd_handle_irq(ism->smcd, bit + ISM_DMB_BIT_OFFSET, dmbemask);
+               clt = clients[ism->sba_client_arr[bit]];
+               clt->handle_irq(ism, bit + ISM_DMB_BIT_OFFSET, dmbemask);
        }
 
        if (ism->sba->e) {
@@ -497,10 +579,21 @@ static const struct smcd_ops ism_ops = {
        .get_chid = ism_get_chid,
 };
 
+static void ism_dev_add_work_func(struct work_struct *work)
+{
+       struct ism_client *client = container_of(work, struct ism_client,
+                                                add_work);
+
+       client->add(client->tgt_ism);
+       atomic_dec(&client->tgt_ism->add_dev_cnt);
+       wake_up(&client->tgt_ism->waitq);
+}
+
 static int ism_dev_init(struct ism_dev *ism)
 {
        struct pci_dev *pdev = ism->pdev;
-       int ret;
+       unsigned long flags;
+       int i, ret;
 
        ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
        if (ret <= 0)
@@ -527,6 +620,28 @@ static int ism_dev_init(struct ism_dev *ism)
                /* hardware is V2 capable */
                ism_create_system_eid();
 
+       init_waitqueue_head(&ism->waitq);
+       atomic_set(&ism->free_clients_cnt, 0);
+       atomic_set(&ism->add_dev_cnt, 0);
+
+       wait_event(ism->waitq, !atomic_read(&ism->add_dev_cnt));
+       spin_lock_irqsave(&clients_lock, flags);
+       for (i = 0; i < max_client; ++i)
+               if (clients[i]) {
+                       INIT_WORK(&clients[i]->add_work,
+                                 ism_dev_add_work_func);
+                       clients[i]->tgt_ism = ism;
+                       atomic_inc(&ism->add_dev_cnt);
+                       schedule_work(&clients[i]->add_work);
+               }
+       spin_unlock_irqrestore(&clients_lock, flags);
+
+       wait_event(ism->waitq, !atomic_read(&ism->add_dev_cnt));
+
+       mutex_lock(&ism_dev_list.mutex);
+       list_add(&ism->list, &ism_dev_list.list);
+       mutex_unlock(&ism_dev_list.mutex);
+
        ret = smcd_register_dev(ism->smcd);
        if (ret)
                goto unreg_ieq;
@@ -602,9 +717,36 @@ err:
        return ret;
 }
 
+static void ism_dev_remove_work_func(struct work_struct *work)
+{
+       struct ism_client *client = container_of(work, struct ism_client,
+                                                remove_work);
+
+       client->remove(client->tgt_ism);
+       atomic_dec(&client->tgt_ism->free_clients_cnt);
+       wake_up(&client->tgt_ism->waitq);
+}
+
+/* Callers must hold ism_dev_list.mutex */
 static void ism_dev_exit(struct ism_dev *ism)
 {
        struct pci_dev *pdev = ism->pdev;
+       unsigned long flags;
+       int i;
+
+       wait_event(ism->waitq, !atomic_read(&ism->free_clients_cnt));
+       spin_lock_irqsave(&clients_lock, flags);
+       for (i = 0; i < max_client; ++i)
+               if (clients[i]) {
+                       INIT_WORK(&clients[i]->remove_work,
+                                 ism_dev_remove_work_func);
+                       clients[i]->tgt_ism = ism;
+                       atomic_inc(&ism->free_clients_cnt);
+                       schedule_work(&clients[i]->remove_work);
+               }
+       spin_unlock_irqrestore(&clients_lock, flags);
+
+       wait_event(ism->waitq, !atomic_read(&ism->free_clients_cnt));
 
        smcd_unregister_dev(ism->smcd);
        if (SYSTEM_EID.serial_number[0] != '0' ||
@@ -614,18 +756,22 @@ static void ism_dev_exit(struct ism_dev *ism)
        unregister_sba(ism);
        free_irq(pci_irq_vector(pdev, 0), ism);
        pci_free_irq_vectors(pdev);
+       list_del_init(&ism->list);
 }
 
 static void ism_remove(struct pci_dev *pdev)
 {
        struct ism_dev *ism = dev_get_drvdata(&pdev->dev);
 
+       mutex_lock(&ism_dev_list.mutex);
        ism_dev_exit(ism);
+       mutex_unlock(&ism_dev_list.mutex);
 
        smcd_free_dev(ism->smcd);
        pci_clear_master(pdev);
        pci_release_mem_regions(pdev);
        pci_disable_device(pdev);
+       device_del(&ism->dev);
        dev_set_drvdata(&pdev->dev, NULL);
        kfree(ism);
 }
@@ -645,6 +791,8 @@ static int __init ism_init(void)
        if (!ism_debug_info)
                return -ENODEV;
 
+       memset(clients, 0, sizeof(clients));
+       max_client = 0;
        debug_register_view(ism_debug_info, &debug_hex_ascii_view);
        ret = pci_register_driver(&ism_driver);
        if (ret)
@@ -655,6 +803,14 @@ static int __init ism_init(void)
 
 static void __exit ism_exit(void)
 {
+       struct ism_dev *ism;
+
+       mutex_lock(&ism_dev_list.mutex);
+       list_for_each_entry(ism, &ism_dev_list.list, list) {
+               ism_dev_exit(ism);
+       }
+       mutex_unlock(&ism_dev_list.mutex);
+
        pci_unregister_driver(&ism_driver);
        debug_unregister(ism_debug_info);
 }
index 69bfbf0..55c8ad3 100644 (file)
@@ -9,6 +9,8 @@
 #ifndef _ISM_H
 #define _ISM_H
 
+#include <linux/workqueue.h>
+
 struct ism_dmb {
        u64 dmb_tok;
        u64 rgid;
@@ -20,4 +22,69 @@ struct ism_dmb {
        dma_addr_t dma_addr;
 };
 
+/* Unless we gain unexpected popularity, this limit should hold for a while */
+#define MAX_CLIENTS            8
+#define ISM_NR_DMBS            1920
+
+struct ism_dev {
+       spinlock_t lock; /* protects the ism device */
+       struct list_head list;
+       struct pci_dev *pdev;
+       struct smcd_dev *smcd;
+
+       struct ism_sba *sba;
+       dma_addr_t sba_dma_addr;
+       DECLARE_BITMAP(sba_bitmap, ISM_NR_DMBS);
+       u8 *sba_client_arr;     /* entries are indices into 'clients' array */
+       void *priv[MAX_CLIENTS];
+
+       struct ism_eq *ieq;
+       dma_addr_t ieq_dma_addr;
+
+       struct device dev;
+       u64 local_gid;
+       int ieq_idx;
+
+       atomic_t free_clients_cnt;
+       atomic_t add_dev_cnt;
+       wait_queue_head_t waitq;
+};
+
+struct ism_event {
+       u32 type;
+       u32 code;
+       u64 tok;
+       u64 time;
+       u64 info;
+};
+
+struct ism_client {
+       const char *name;
+       void (*add)(struct ism_dev *dev);
+       void (*remove)(struct ism_dev *dev);
+       void (*handle_event)(struct ism_dev *dev, struct ism_event *event);
+       /* Parameter dmbemask contains a bit vector with updated DMBEs, if sent
+        * via ism_move_data(). Callback function must handle all active bits
+        * indicated by dmbemask.
+        */
+       void (*handle_irq)(struct ism_dev *dev, unsigned int bit, u16 dmbemask);
+       /* Private area - don't touch! */
+       struct work_struct remove_work;
+       struct work_struct add_work;
+       struct ism_dev *tgt_ism;
+       u8 id;
+};
+
+int ism_register_client(struct ism_client *client);
+int  ism_unregister_client(struct ism_client *client);
+static inline void *ism_get_priv(struct ism_dev *dev,
+                                struct ism_client *client) {
+       return dev->priv[client->id];
+}
+
+static inline void ism_set_priv(struct ism_dev *dev, struct ism_client *client,
+                               void *priv) {
+       dev->priv[client->id] = priv;
+}
+
 #endif /* _ISM_H */
index c926d33..98689b1 100644 (file)
@@ -15,6 +15,7 @@
 #include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/wait.h>
+#include "linux/ism.h"
 
 struct sock;
 
@@ -48,14 +49,6 @@ struct smcd_dmb {
 
 #define ISM_ERROR      0xFFFF
 
-struct smcd_event {
-       u32 type;
-       u32 code;
-       u64 tok;
-       u64 time;
-       u64 info;
-};
-
 struct smcd_dev;
 
 struct smcd_ops {
@@ -100,6 +93,6 @@ struct smcd_dev *smcd_alloc_dev(struct device *parent, const char *name,
 int smcd_register_dev(struct smcd_dev *smcd);
 void smcd_unregister_dev(struct smcd_dev *smcd);
 void smcd_free_dev(struct smcd_dev *smcd);
-void smcd_handle_event(struct smcd_dev *dev, struct smcd_event *event);
+void smcd_handle_event(struct smcd_dev *dev, struct ism_event *event);
 void smcd_handle_irq(struct smcd_dev *dev, unsigned int bit, u16 dmbemask);
 #endif /* _SMC_H */
index 28e1641..2154098 100644 (file)
@@ -296,7 +296,7 @@ int smcd_nl_get_device(struct sk_buff *skb, struct netlink_callback *cb)
 struct smc_ism_event_work {
        struct work_struct work;
        struct smcd_dev *smcd;
-       struct smcd_event event;
+       struct ism_event event;
 };
 
 #define ISM_EVENT_REQUEST              0x0001
@@ -490,7 +490,7 @@ EXPORT_SYMBOL_GPL(smcd_free_dev);
  * Context:
  * - Function called in IRQ context from ISM device driver event handler.
  */
-void smcd_handle_event(struct smcd_dev *smcd, struct smcd_event *event)
+void smcd_handle_event(struct smcd_dev *smcd, struct ism_event *event)
 {
        struct smc_ism_event_work *wrk;