OpenCloudOS-Kernel/drivers/s390/net/ism_drv.c

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// SPDX-License-Identifier: GPL-2.0
/*
* ISM driver for s390.
*
* Copyright IBM Corp. 2018
*/
#define KMSG_COMPONENT "ism"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/ctype.h>
#include <linux/processor.h>
#include "ism.h"
MODULE_DESCRIPTION("ISM driver for s390");
MODULE_LICENSE("GPL");
#define PCI_DEVICE_ID_IBM_ISM 0x04ED
#define DRV_NAME "ism"
static const struct pci_device_id ism_device_table[] = {
{ PCI_VDEVICE(IBM, PCI_DEVICE_ID_IBM_ISM), 0 },
{ 0, }
};
MODULE_DEVICE_TABLE(pci, ism_device_table);
static debug_info_t *ism_debug_info;
#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;
s390/ism: Fix and simplify add()/remove() callback handling Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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static DEFINE_MUTEX(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),
};
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static void ism_setup_forwarding(struct ism_client *client, struct ism_dev *ism)
{
unsigned long flags;
spin_lock_irqsave(&ism->lock, flags);
ism->subs[client->id] = client;
spin_unlock_irqrestore(&ism->lock, flags);
}
int ism_register_client(struct ism_client *client)
{
struct ism_dev *ism;
int i, rc = -ENOSPC;
mutex_lock(&ism_dev_list.mutex);
s390/ism: Fix and simplify add()/remove() callback handling Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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mutex_lock(&clients_lock);
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;
}
}
s390/ism: Fix and simplify add()/remove() callback handling Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-07-07 18:56:21 +08:00
mutex_unlock(&clients_lock);
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);
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ism_setup_forwarding(client, 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);
list_for_each_entry(ism, &ism_dev_list.list, list) {
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spin_lock_irqsave(&ism->lock, flags);
/* Stop forwarding IRQs and events */
ism->subs[client->id] = NULL;
for (int i = 0; i < ISM_NR_DMBS; ++i) {
if (ism->sba_client_arr[i] == client->id) {
WARN(1, "%s: attempt to unregister '%s' with registered dmb(s)\n",
__func__, client->name);
rc = -EBUSY;
goto err_reg_dmb;
}
}
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spin_unlock_irqrestore(&ism->lock, flags);
}
mutex_unlock(&ism_dev_list.mutex);
mutex_lock(&clients_lock);
clients[client->id] = NULL;
if (client->id + 1 == max_client)
max_client--;
mutex_unlock(&clients_lock);
return rc;
err_reg_dmb:
spin_unlock_irqrestore(&ism->lock, flags);
mutex_unlock(&ism_dev_list.mutex);
return rc;
}
EXPORT_SYMBOL_GPL(ism_unregister_client);
static int ism_cmd(struct ism_dev *ism, void *cmd)
{
struct ism_req_hdr *req = cmd;
struct ism_resp_hdr *resp = cmd;
__ism_write_cmd(ism, req + 1, sizeof(*req), req->len - sizeof(*req));
__ism_write_cmd(ism, req, 0, sizeof(*req));
WRITE_ONCE(resp->ret, ISM_ERROR);
__ism_read_cmd(ism, resp, 0, sizeof(*resp));
if (resp->ret) {
debug_text_event(ism_debug_info, 0, "cmd failure");
debug_event(ism_debug_info, 0, resp, sizeof(*resp));
goto out;
}
__ism_read_cmd(ism, resp + 1, sizeof(*resp), resp->len - sizeof(*resp));
out:
return resp->ret;
}
static int ism_cmd_simple(struct ism_dev *ism, u32 cmd_code)
{
union ism_cmd_simple cmd;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = cmd_code;
cmd.request.hdr.len = sizeof(cmd.request);
return ism_cmd(ism, &cmd);
}
static int query_info(struct ism_dev *ism)
{
union ism_qi cmd;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = ISM_QUERY_INFO;
cmd.request.hdr.len = sizeof(cmd.request);
if (ism_cmd(ism, &cmd))
goto out;
debug_text_event(ism_debug_info, 3, "query info");
debug_event(ism_debug_info, 3, &cmd.response, sizeof(cmd.response));
out:
return 0;
}
static int register_sba(struct ism_dev *ism)
{
union ism_reg_sba cmd;
dma_addr_t dma_handle;
struct ism_sba *sba;
sba = dma_alloc_coherent(&ism->pdev->dev, PAGE_SIZE, &dma_handle,
GFP_KERNEL);
if (!sba)
return -ENOMEM;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = ISM_REG_SBA;
cmd.request.hdr.len = sizeof(cmd.request);
cmd.request.sba = dma_handle;
if (ism_cmd(ism, &cmd)) {
dma_free_coherent(&ism->pdev->dev, PAGE_SIZE, sba, dma_handle);
return -EIO;
}
ism->sba = sba;
ism->sba_dma_addr = dma_handle;
return 0;
}
static int register_ieq(struct ism_dev *ism)
{
union ism_reg_ieq cmd;
dma_addr_t dma_handle;
struct ism_eq *ieq;
ieq = dma_alloc_coherent(&ism->pdev->dev, PAGE_SIZE, &dma_handle,
GFP_KERNEL);
if (!ieq)
return -ENOMEM;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = ISM_REG_IEQ;
cmd.request.hdr.len = sizeof(cmd.request);
cmd.request.ieq = dma_handle;
cmd.request.len = sizeof(*ieq);
if (ism_cmd(ism, &cmd)) {
dma_free_coherent(&ism->pdev->dev, PAGE_SIZE, ieq, dma_handle);
return -EIO;
}
ism->ieq = ieq;
ism->ieq_idx = -1;
ism->ieq_dma_addr = dma_handle;
return 0;
}
static int unregister_sba(struct ism_dev *ism)
{
int ret;
if (!ism->sba)
return 0;
ret = ism_cmd_simple(ism, ISM_UNREG_SBA);
if (ret && ret != ISM_ERROR)
return -EIO;
dma_free_coherent(&ism->pdev->dev, PAGE_SIZE,
ism->sba, ism->sba_dma_addr);
ism->sba = NULL;
ism->sba_dma_addr = 0;
return 0;
}
static int unregister_ieq(struct ism_dev *ism)
{
int ret;
if (!ism->ieq)
return 0;
ret = ism_cmd_simple(ism, ISM_UNREG_IEQ);
if (ret && ret != ISM_ERROR)
return -EIO;
dma_free_coherent(&ism->pdev->dev, PAGE_SIZE,
ism->ieq, ism->ieq_dma_addr);
ism->ieq = NULL;
ism->ieq_dma_addr = 0;
return 0;
}
static int ism_read_local_gid(struct ism_dev *ism)
{
union ism_read_gid cmd;
int ret;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = ISM_READ_GID;
cmd.request.hdr.len = sizeof(cmd.request);
ret = ism_cmd(ism, &cmd);
if (ret)
goto out;
ism->local_gid = cmd.response.gid;
out:
return ret;
}
static void ism_free_dmb(struct ism_dev *ism, struct ism_dmb *dmb)
{
clear_bit(dmb->sba_idx, ism->sba_bitmap);
dma_free_coherent(&ism->pdev->dev, dmb->dmb_len,
dmb->cpu_addr, dmb->dma_addr);
}
static int ism_alloc_dmb(struct ism_dev *ism, struct ism_dmb *dmb)
{
unsigned long bit;
if (PAGE_ALIGN(dmb->dmb_len) > dma_get_max_seg_size(&ism->pdev->dev))
return -EINVAL;
if (!dmb->sba_idx) {
bit = find_next_zero_bit(ism->sba_bitmap, ISM_NR_DMBS,
ISM_DMB_BIT_OFFSET);
if (bit == ISM_NR_DMBS)
return -ENOSPC;
dmb->sba_idx = bit;
}
if (dmb->sba_idx < ISM_DMB_BIT_OFFSET ||
test_and_set_bit(dmb->sba_idx, ism->sba_bitmap))
return -EINVAL;
dmb->cpu_addr = dma_alloc_coherent(&ism->pdev->dev, dmb->dmb_len,
&dmb->dma_addr,
GFP_KERNEL | __GFP_NOWARN |
__GFP_NOMEMALLOC | __GFP_NORETRY);
if (!dmb->cpu_addr)
clear_bit(dmb->sba_idx, ism->sba_bitmap);
return dmb->cpu_addr ? 0 : -ENOMEM;
}
int ism_register_dmb(struct ism_dev *ism, struct ism_dmb *dmb,
struct ism_client *client)
{
union ism_reg_dmb cmd;
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unsigned long flags;
int ret;
ret = ism_alloc_dmb(ism, dmb);
if (ret)
goto out;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = ISM_REG_DMB;
cmd.request.hdr.len = sizeof(cmd.request);
cmd.request.dmb = dmb->dma_addr;
cmd.request.dmb_len = dmb->dmb_len;
cmd.request.sba_idx = dmb->sba_idx;
cmd.request.vlan_valid = dmb->vlan_valid;
cmd.request.vlan_id = dmb->vlan_id;
cmd.request.rgid = dmb->rgid;
ret = ism_cmd(ism, &cmd);
if (ret) {
ism_free_dmb(ism, dmb);
goto out;
}
dmb->dmb_tok = cmd.response.dmb_tok;
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spin_lock_irqsave(&ism->lock, flags);
ism->sba_client_arr[dmb->sba_idx - ISM_DMB_BIT_OFFSET] = client->id;
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spin_unlock_irqrestore(&ism->lock, flags);
out:
return ret;
}
EXPORT_SYMBOL_GPL(ism_register_dmb);
int ism_unregister_dmb(struct ism_dev *ism, struct ism_dmb *dmb)
{
union ism_unreg_dmb cmd;
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unsigned long flags;
int ret;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = ISM_UNREG_DMB;
cmd.request.hdr.len = sizeof(cmd.request);
cmd.request.dmb_tok = dmb->dmb_tok;
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spin_lock_irqsave(&ism->lock, flags);
ism->sba_client_arr[dmb->sba_idx - ISM_DMB_BIT_OFFSET] = NO_CLIENT;
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spin_unlock_irqrestore(&ism->lock, flags);
ret = ism_cmd(ism, &cmd);
if (ret && ret != ISM_ERROR)
goto out;
ism_free_dmb(ism, dmb);
out:
return ret;
}
EXPORT_SYMBOL_GPL(ism_unregister_dmb);
static int ism_add_vlan_id(struct ism_dev *ism, u64 vlan_id)
{
union ism_set_vlan_id cmd;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = ISM_ADD_VLAN_ID;
cmd.request.hdr.len = sizeof(cmd.request);
cmd.request.vlan_id = vlan_id;
return ism_cmd(ism, &cmd);
}
static int ism_del_vlan_id(struct ism_dev *ism, u64 vlan_id)
{
union ism_set_vlan_id cmd;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = ISM_DEL_VLAN_ID;
cmd.request.hdr.len = sizeof(cmd.request);
cmd.request.vlan_id = vlan_id;
return ism_cmd(ism, &cmd);
}
static unsigned int max_bytes(unsigned int start, unsigned int len,
unsigned int boundary)
{
return min(boundary - (start & (boundary - 1)), len);
}
int ism_move(struct ism_dev *ism, u64 dmb_tok, unsigned int idx, bool sf,
unsigned int offset, void *data, unsigned int size)
{
unsigned int bytes;
u64 dmb_req;
int ret;
while (size) {
bytes = max_bytes(offset, size, PAGE_SIZE);
dmb_req = ISM_CREATE_REQ(dmb_tok, idx, size == bytes ? sf : 0,
offset);
ret = __ism_move(ism, dmb_req, data, bytes);
if (ret)
return ret;
size -= bytes;
data += bytes;
offset += bytes;
}
return 0;
}
EXPORT_SYMBOL_GPL(ism_move);
static struct ism_systemeid SYSTEM_EID = {
.seid_string = "IBM-SYSZ-ISMSEID00000000",
.serial_number = "0000",
.type = "0000",
};
static void ism_create_system_eid(void)
{
struct cpuid id;
u16 ident_tail;
char tmp[5];
get_cpu_id(&id);
ident_tail = (u16)(id.ident & ISM_IDENT_MASK);
snprintf(tmp, 5, "%04X", ident_tail);
memcpy(&SYSTEM_EID.serial_number, tmp, 4);
snprintf(tmp, 5, "%04X", id.machine);
memcpy(&SYSTEM_EID.type, tmp, 4);
}
u8 *ism_get_seid(void)
{
return SYSTEM_EID.seid_string;
}
EXPORT_SYMBOL_GPL(ism_get_seid);
static void ism_handle_event(struct ism_dev *ism)
{
struct ism_event *entry;
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struct ism_client *clt;
int i;
while ((ism->ieq_idx + 1) != READ_ONCE(ism->ieq->header.idx)) {
if (++(ism->ieq_idx) == ARRAY_SIZE(ism->ieq->entry))
ism->ieq_idx = 0;
entry = &ism->ieq->entry[ism->ieq_idx];
debug_event(ism_debug_info, 2, entry, sizeof(*entry));
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for (i = 0; i < max_client; ++i) {
clt = ism->subs[i];
if (clt)
clt->handle_event(ism, entry);
}
}
}
static irqreturn_t ism_handle_irq(int irq, void *data)
{
struct ism_dev *ism = data;
unsigned long bit, end;
unsigned long *bv;
u16 dmbemask;
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u8 client_id;
bv = (void *) &ism->sba->dmb_bits[ISM_DMB_WORD_OFFSET];
end = sizeof(ism->sba->dmb_bits) * BITS_PER_BYTE - ISM_DMB_BIT_OFFSET;
spin_lock(&ism->lock);
ism->sba->s = 0;
barrier();
for (bit = 0;;) {
bit = find_next_bit_inv(bv, end, bit);
if (bit >= end)
break;
clear_bit_inv(bit, bv);
dmbemask = ism->sba->dmbe_mask[bit + ISM_DMB_BIT_OFFSET];
ism->sba->dmbe_mask[bit + ISM_DMB_BIT_OFFSET] = 0;
barrier();
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client_id = ism->sba_client_arr[bit];
if (unlikely(client_id == NO_CLIENT || !ism->subs[client_id]))
continue;
ism->subs[client_id]->handle_irq(ism, bit + ISM_DMB_BIT_OFFSET, dmbemask);
}
if (ism->sba->e) {
ism->sba->e = 0;
barrier();
ism_handle_event(ism);
}
spin_unlock(&ism->lock);
return IRQ_HANDLED;
}
static int ism_dev_init(struct ism_dev *ism)
{
struct pci_dev *pdev = ism->pdev;
int i, ret;
ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
if (ret <= 0)
goto out;
ism->sba_client_arr = kzalloc(ISM_NR_DMBS, GFP_KERNEL);
if (!ism->sba_client_arr)
goto free_vectors;
memset(ism->sba_client_arr, NO_CLIENT, ISM_NR_DMBS);
ret = request_irq(pci_irq_vector(pdev, 0), ism_handle_irq, 0,
pci_name(pdev), ism);
if (ret)
goto free_client_arr;
ret = register_sba(ism);
if (ret)
goto free_irq;
ret = register_ieq(ism);
if (ret)
goto unreg_sba;
ret = ism_read_local_gid(ism);
if (ret)
goto unreg_ieq;
if (!ism_add_vlan_id(ism, ISM_RESERVED_VLANID))
/* hardware is V2 capable */
ism_create_system_eid();
s390/ism: Fix and simplify add()/remove() callback handling Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-07-07 18:56:21 +08:00
mutex_lock(&ism_dev_list.mutex);
mutex_lock(&clients_lock);
for (i = 0; i < max_client; ++i) {
if (clients[i]) {
s390/ism: Fix and simplify add()/remove() callback handling Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-07-07 18:56:21 +08:00
clients[i]->add(ism);
ism_setup_forwarding(clients[i], ism);
}
s390/ism: Fix and simplify add()/remove() callback handling Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-07-07 18:56:21 +08:00
}
mutex_unlock(&clients_lock);
list_add(&ism->list, &ism_dev_list.list);
mutex_unlock(&ism_dev_list.mutex);
query_info(ism);
return 0;
unreg_ieq:
unregister_ieq(ism);
unreg_sba:
unregister_sba(ism);
free_irq:
free_irq(pci_irq_vector(pdev, 0), ism);
free_client_arr:
kfree(ism->sba_client_arr);
free_vectors:
pci_free_irq_vectors(pdev);
out:
return ret;
}
static int ism_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
struct ism_dev *ism;
int ret;
ism = kzalloc(sizeof(*ism), GFP_KERNEL);
if (!ism)
return -ENOMEM;
spin_lock_init(&ism->lock);
dev_set_drvdata(&pdev->dev, ism);
ism->pdev = pdev;
ism->dev.parent = &pdev->dev;
device_initialize(&ism->dev);
dev_set_name(&ism->dev, dev_name(&pdev->dev));
ret = device_add(&ism->dev);
if (ret)
goto err_dev;
ret = pci_enable_device_mem(pdev);
if (ret)
goto err;
ret = pci_request_mem_regions(pdev, DRV_NAME);
if (ret)
goto err_disable;
ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
if (ret)
goto err_resource;
dma_set_seg_boundary(&pdev->dev, SZ_1M - 1);
dma_set_max_seg_size(&pdev->dev, SZ_1M);
pci_set_master(pdev);
ret = ism_dev_init(ism);
if (ret)
goto err_resource;
return 0;
err_resource:
pci_release_mem_regions(pdev);
err_disable:
pci_disable_device(pdev);
err:
device_del(&ism->dev);
err_dev:
dev_set_drvdata(&pdev->dev, NULL);
kfree(ism);
return ret;
}
static void ism_dev_exit(struct ism_dev *ism)
{
struct pci_dev *pdev = ism->pdev;
unsigned long flags;
int i;
s390/ism: Fix and simplify add()/remove() callback handling Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-07-07 18:56:21 +08:00
spin_lock_irqsave(&ism->lock, flags);
for (i = 0; i < max_client; ++i)
s390/ism: Fix and simplify add()/remove() callback handling Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-07-07 18:56:21 +08:00
ism->subs[i] = NULL;
spin_unlock_irqrestore(&ism->lock, flags);
s390/ism: Fix and simplify add()/remove() callback handling Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-07-07 18:56:21 +08:00
mutex_lock(&ism_dev_list.mutex);
mutex_lock(&clients_lock);
for (i = 0; i < max_client; ++i) {
if (clients[i])
clients[i]->remove(ism);
}
mutex_unlock(&clients_lock);
if (SYSTEM_EID.serial_number[0] != '0' ||
SYSTEM_EID.type[0] != '0')
ism_del_vlan_id(ism, ISM_RESERVED_VLANID);
unregister_ieq(ism);
unregister_sba(ism);
free_irq(pci_irq_vector(pdev, 0), ism);
kfree(ism->sba_client_arr);
pci_free_irq_vectors(pdev);
list_del_init(&ism->list);
s390/ism: Fix and simplify add()/remove() callback handling Previously the clients_lock was protecting the clients array against concurrent addition/removal of clients but was also accessed from IRQ context. This meant that it had to be a spinlock and that the add() and remove() callbacks in which clients need to do allocation and take mutexes can't be called under the clients_lock. To work around this these callbacks were moved to workqueues. This not only introduced significant complexity but is also subtly broken in at least one way. In ism_dev_init() and ism_dev_exit() clients[i]->tgt_ism is used to communicate the added/removed ISM device to the work function. While write access to client[i]->tgt_ism is protected by the clients_lock and the code waits that there is no pending add/remove work before and after setting clients[i]->tgt_ism this is not enough. The problem is that the wait happens based on per ISM device counters. Thus a concurrent ism_dev_init()/ism_dev_exit() for a different ISM device may overwrite a clients[i]->tgt_ism between unlocking the clients_lock and the subsequent wait for the work to finnish. Thankfully with the clients_lock no longer held in IRQ context it can be turned into a mutex which can be held during the calls to add()/remove() completely removing the need for the workqueues and the associated broken housekeeping including the per ISM device counters and the clients[i]->tgt_ism. Fixes: 89e7d2ba61b7 ("net/ism: Add new API for client registration") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-07-07 18:56:21 +08:00
mutex_unlock(&ism_dev_list.mutex);
}
static void ism_remove(struct pci_dev *pdev)
{
struct ism_dev *ism = dev_get_drvdata(&pdev->dev);
ism_dev_exit(ism);
pci_release_mem_regions(pdev);
pci_disable_device(pdev);
device_del(&ism->dev);
dev_set_drvdata(&pdev->dev, NULL);
kfree(ism);
}
static struct pci_driver ism_driver = {
.name = DRV_NAME,
.id_table = ism_device_table,
.probe = ism_probe,
.remove = ism_remove,
};
static int __init ism_init(void)
{
int ret;
ism_debug_info = debug_register("ism", 2, 1, 16);
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)
debug_unregister(ism_debug_info);
return ret;
}
static void __exit ism_exit(void)
{
pci_unregister_driver(&ism_driver);
debug_unregister(ism_debug_info);
}
module_init(ism_init);
module_exit(ism_exit);
/*************************** SMC-D Implementation *****************************/
#if IS_ENABLED(CONFIG_SMC)
static int ism_query_rgid(struct ism_dev *ism, u64 rgid, u32 vid_valid,
u32 vid)
{
union ism_query_rgid cmd;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = ISM_QUERY_RGID;
cmd.request.hdr.len = sizeof(cmd.request);
cmd.request.rgid = rgid;
cmd.request.vlan_valid = vid_valid;
cmd.request.vlan_id = vid;
return ism_cmd(ism, &cmd);
}
static int smcd_query_rgid(struct smcd_dev *smcd, u64 rgid, u32 vid_valid,
u32 vid)
{
return ism_query_rgid(smcd->priv, rgid, vid_valid, vid);
}
static int smcd_register_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb,
struct ism_client *client)
{
return ism_register_dmb(smcd->priv, (struct ism_dmb *)dmb, client);
}
static int smcd_unregister_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb)
{
return ism_unregister_dmb(smcd->priv, (struct ism_dmb *)dmb);
}
static int smcd_add_vlan_id(struct smcd_dev *smcd, u64 vlan_id)
{
return ism_add_vlan_id(smcd->priv, vlan_id);
}
static int smcd_del_vlan_id(struct smcd_dev *smcd, u64 vlan_id)
{
return ism_del_vlan_id(smcd->priv, vlan_id);
}
static int smcd_set_vlan_required(struct smcd_dev *smcd)
{
return ism_cmd_simple(smcd->priv, ISM_SET_VLAN);
}
static int smcd_reset_vlan_required(struct smcd_dev *smcd)
{
return ism_cmd_simple(smcd->priv, ISM_RESET_VLAN);
}
static int ism_signal_ieq(struct ism_dev *ism, u64 rgid, u32 trigger_irq,
u32 event_code, u64 info)
{
union ism_sig_ieq cmd;
memset(&cmd, 0, sizeof(cmd));
cmd.request.hdr.cmd = ISM_SIGNAL_IEQ;
cmd.request.hdr.len = sizeof(cmd.request);
cmd.request.rgid = rgid;
cmd.request.trigger_irq = trigger_irq;
cmd.request.event_code = event_code;
cmd.request.info = info;
return ism_cmd(ism, &cmd);
}
static int smcd_signal_ieq(struct smcd_dev *smcd, u64 rgid, u32 trigger_irq,
u32 event_code, u64 info)
{
return ism_signal_ieq(smcd->priv, rgid, trigger_irq, event_code, info);
}
static int smcd_move(struct smcd_dev *smcd, u64 dmb_tok, unsigned int idx,
bool sf, unsigned int offset, void *data,
unsigned int size)
{
return ism_move(smcd->priv, dmb_tok, idx, sf, offset, data, size);
}
static int smcd_supports_v2(void)
{
return SYSTEM_EID.serial_number[0] != '0' ||
SYSTEM_EID.type[0] != '0';
}
static u64 ism_get_local_gid(struct ism_dev *ism)
{
return ism->local_gid;
}
static u64 smcd_get_local_gid(struct smcd_dev *smcd)
{
return ism_get_local_gid(smcd->priv);
}
static u16 ism_get_chid(struct ism_dev *ism)
{
if (!ism || !ism->pdev)
return 0;
return to_zpci(ism->pdev)->pchid;
}
static u16 smcd_get_chid(struct smcd_dev *smcd)
{
return ism_get_chid(smcd->priv);
}
static inline struct device *smcd_get_dev(struct smcd_dev *dev)
{
struct ism_dev *ism = dev->priv;
return &ism->dev;
}
static const struct smcd_ops ism_ops = {
.query_remote_gid = smcd_query_rgid,
.register_dmb = smcd_register_dmb,
.unregister_dmb = smcd_unregister_dmb,
.add_vlan_id = smcd_add_vlan_id,
.del_vlan_id = smcd_del_vlan_id,
.set_vlan_required = smcd_set_vlan_required,
.reset_vlan_required = smcd_reset_vlan_required,
.signal_event = smcd_signal_ieq,
.move_data = smcd_move,
.supports_v2 = smcd_supports_v2,
.get_system_eid = ism_get_seid,
.get_local_gid = smcd_get_local_gid,
.get_chid = smcd_get_chid,
.get_dev = smcd_get_dev,
};
const struct smcd_ops *ism_get_smcd_ops(void)
{
return &ism_ops;
}
EXPORT_SYMBOL_GPL(ism_get_smcd_ops);
#endif