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firewire: sbp2: replace card lock by target lock
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firewire-core uses fw_card.lock to protect topology data and transaction
data.  firewire-sbp2 uses fw_card.lock for entirely unrelated purposes.

Introduce a sbp2_target.lock to firewire-sbp2 and replace all
fw_card.lock uses in the driver.  fw_card.lock is now entirely private
to firewire-core.  This has no immediate advantage apart from making it
clear in the code that firewire-sbp2 does not interact with the core
via the core lock.

Signed-off-by: Stefan Richter <[email protected]>
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Stefan Richter committed Dec 10, 2014
1 parent 8e045a3 commit d737d7d
Showing 1 changed file with 29 additions and 31 deletions.
60 changes: 29 additions & 31 deletions drivers/firewire/sbp2.c
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Original file line number Diff line number Diff line change
Expand Up @@ -174,6 +174,7 @@ struct sbp2_target {
unsigned int mgt_orb_timeout;
unsigned int max_payload;

spinlock_t lock;
int dont_block; /* counter for each logical unit */
int blocked; /* ditto */
};
Expand Down Expand Up @@ -270,6 +271,7 @@ struct sbp2_orb {
dma_addr_t request_bus;
int rcode;
void (*callback)(struct sbp2_orb * orb, struct sbp2_status * status);
struct sbp2_logical_unit *lu;
struct list_head link;
};

Expand Down Expand Up @@ -321,7 +323,6 @@ struct sbp2_command_orb {
u8 command_block[SBP2_MAX_CDB_SIZE];
} request;
struct scsi_cmnd *cmd;
struct sbp2_logical_unit *lu;

struct sbp2_pointer page_table[SG_ALL] __attribute__((aligned(8)));
dma_addr_t page_table_bus;
Expand Down Expand Up @@ -444,7 +445,7 @@ static void sbp2_status_write(struct fw_card *card, struct fw_request *request,
}

/* Lookup the orb corresponding to this status write. */
spin_lock_irqsave(&card->lock, flags);
spin_lock_irqsave(&lu->tgt->lock, flags);
list_for_each_entry(orb, &lu->orb_list, link) {
if (STATUS_GET_ORB_HIGH(status) == 0 &&
STATUS_GET_ORB_LOW(status) == orb->request_bus) {
Expand All @@ -453,7 +454,7 @@ static void sbp2_status_write(struct fw_card *card, struct fw_request *request,
break;
}
}
spin_unlock_irqrestore(&card->lock, flags);
spin_unlock_irqrestore(&lu->tgt->lock, flags);

if (&orb->link != &lu->orb_list) {
orb->callback(orb, &status);
Expand All @@ -480,18 +481,18 @@ static void complete_transaction(struct fw_card *card, int rcode,
* been set and only does the cleanup if the transaction
* failed and we didn't already get a status write.
*/
spin_lock_irqsave(&card->lock, flags);
spin_lock_irqsave(&orb->lu->tgt->lock, flags);

if (orb->rcode == -1)
orb->rcode = rcode;
if (orb->rcode != RCODE_COMPLETE) {
list_del(&orb->link);
spin_unlock_irqrestore(&card->lock, flags);
spin_unlock_irqrestore(&orb->lu->tgt->lock, flags);

orb->callback(orb, NULL);
kref_put(&orb->kref, free_orb); /* orb callback reference */
} else {
spin_unlock_irqrestore(&card->lock, flags);
spin_unlock_irqrestore(&orb->lu->tgt->lock, flags);
}

kref_put(&orb->kref, free_orb); /* transaction callback reference */
Expand All @@ -507,9 +508,10 @@ static void sbp2_send_orb(struct sbp2_orb *orb, struct sbp2_logical_unit *lu,
orb_pointer.high = 0;
orb_pointer.low = cpu_to_be32(orb->request_bus);

spin_lock_irqsave(&device->card->lock, flags);
orb->lu = lu;
spin_lock_irqsave(&lu->tgt->lock, flags);
list_add_tail(&orb->link, &lu->orb_list);
spin_unlock_irqrestore(&device->card->lock, flags);
spin_unlock_irqrestore(&lu->tgt->lock, flags);

kref_get(&orb->kref); /* transaction callback reference */
kref_get(&orb->kref); /* orb callback reference */
Expand All @@ -527,9 +529,9 @@ static int sbp2_cancel_orbs(struct sbp2_logical_unit *lu)
int retval = -ENOENT;

INIT_LIST_HEAD(&list);
spin_lock_irq(&device->card->lock);
spin_lock_irq(&lu->tgt->lock);
list_splice_init(&lu->orb_list, &list);
spin_unlock_irq(&device->card->lock);
spin_unlock_irq(&lu->tgt->lock);

list_for_each_entry_safe(orb, next, &list, link) {
retval = 0;
Expand Down Expand Up @@ -686,14 +688,11 @@ static void sbp2_agent_reset_no_wait(struct sbp2_logical_unit *lu)
&d, 4, complete_agent_reset_write_no_wait, t);
}

static inline void sbp2_allow_block(struct sbp2_logical_unit *lu)
static inline void sbp2_allow_block(struct sbp2_target *tgt)
{
struct sbp2_target *tgt = lu->tgt;
struct fw_card *card = target_parent_device(tgt)->card;

spin_lock_irq(&card->lock);
spin_lock_irq(&tgt->lock);
--tgt->dont_block;
spin_unlock_irq(&card->lock);
spin_unlock_irq(&tgt->lock);
}

/*
Expand All @@ -702,7 +701,7 @@ static inline void sbp2_allow_block(struct sbp2_logical_unit *lu)
* logical units have been finished (indicated by dont_block == 0).
* - lu->generation is stale.
*
* Note, scsi_block_requests() must be called while holding card->lock,
* Note, scsi_block_requests() must be called while holding tgt->lock,
* otherwise it might foil sbp2_[conditionally_]unblock()'s attempt to
* unblock the target.
*/
Expand All @@ -714,20 +713,20 @@ static void sbp2_conditionally_block(struct sbp2_logical_unit *lu)
container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
unsigned long flags;

spin_lock_irqsave(&card->lock, flags);
spin_lock_irqsave(&tgt->lock, flags);
if (!tgt->dont_block && !lu->blocked &&
lu->generation != card->generation) {
lu->blocked = true;
if (++tgt->blocked == 1)
scsi_block_requests(shost);
}
spin_unlock_irqrestore(&card->lock, flags);
spin_unlock_irqrestore(&tgt->lock, flags);
}

/*
* Unblocks lu->tgt as soon as all its logical units can be unblocked.
* Note, it is harmless to run scsi_unblock_requests() outside the
* card->lock protected section. On the other hand, running it inside
* tgt->lock protected section. On the other hand, running it inside
* the section might clash with shost->host_lock.
*/
static void sbp2_conditionally_unblock(struct sbp2_logical_unit *lu)
Expand All @@ -738,12 +737,12 @@ static void sbp2_conditionally_unblock(struct sbp2_logical_unit *lu)
container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
bool unblock = false;

spin_lock_irq(&card->lock);
spin_lock_irq(&tgt->lock);
if (lu->blocked && lu->generation == card->generation) {
lu->blocked = false;
unblock = --tgt->blocked == 0;
}
spin_unlock_irq(&card->lock);
spin_unlock_irq(&tgt->lock);

if (unblock)
scsi_unblock_requests(shost);
Expand All @@ -752,18 +751,17 @@ static void sbp2_conditionally_unblock(struct sbp2_logical_unit *lu)
/*
* Prevents future blocking of tgt and unblocks it.
* Note, it is harmless to run scsi_unblock_requests() outside the
* card->lock protected section. On the other hand, running it inside
* tgt->lock protected section. On the other hand, running it inside
* the section might clash with shost->host_lock.
*/
static void sbp2_unblock(struct sbp2_target *tgt)
{
struct fw_card *card = target_parent_device(tgt)->card;
struct Scsi_Host *shost =
container_of((void *)tgt, struct Scsi_Host, hostdata[0]);

spin_lock_irq(&card->lock);
spin_lock_irq(&tgt->lock);
++tgt->dont_block;
spin_unlock_irq(&card->lock);
spin_unlock_irq(&tgt->lock);

scsi_unblock_requests(shost);
}
Expand Down Expand Up @@ -899,7 +897,7 @@ static void sbp2_login(struct work_struct *work)
/* No error during __scsi_add_device() */
lu->has_sdev = true;
scsi_device_put(sdev);
sbp2_allow_block(lu);
sbp2_allow_block(tgt);

return;

Expand Down Expand Up @@ -1158,6 +1156,7 @@ static int sbp2_probe(struct fw_unit *unit, const struct ieee1394_device_id *id)
dev_set_drvdata(&unit->device, tgt);
tgt->unit = unit;
INIT_LIST_HEAD(&tgt->lu_list);
spin_lock_init(&tgt->lock);
tgt->guid = (u64)device->config_rom[3] << 32 | device->config_rom[4];

if (fw_device_enable_phys_dma(device) < 0)
Expand Down Expand Up @@ -1354,12 +1353,12 @@ static void complete_command_orb(struct sbp2_orb *base_orb,
{
struct sbp2_command_orb *orb =
container_of(base_orb, struct sbp2_command_orb, base);
struct fw_device *device = target_parent_device(orb->lu->tgt);
struct fw_device *device = target_parent_device(base_orb->lu->tgt);
int result;

if (status != NULL) {
if (STATUS_GET_DEAD(*status))
sbp2_agent_reset_no_wait(orb->lu);
sbp2_agent_reset_no_wait(base_orb->lu);

switch (STATUS_GET_RESPONSE(*status)) {
case SBP2_STATUS_REQUEST_COMPLETE:
Expand All @@ -1385,7 +1384,7 @@ static void complete_command_orb(struct sbp2_orb *base_orb,
* or when sending the write (less likely).
*/
result = DID_BUS_BUSY << 16;
sbp2_conditionally_block(orb->lu);
sbp2_conditionally_block(base_orb->lu);
}

dma_unmap_single(device->card->device, orb->base.request_bus,
Expand Down Expand Up @@ -1482,7 +1481,6 @@ static int sbp2_scsi_queuecommand(struct Scsi_Host *shost,
/* Initialize rcode to something not RCODE_COMPLETE. */
orb->base.rcode = -1;
kref_init(&orb->base.kref);
orb->lu = lu;
orb->cmd = cmd;
orb->request.next.high = cpu_to_be32(SBP2_ORB_NULL);
orb->request.misc = cpu_to_be32(
Expand Down

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