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IB/ehca: Change idr spinlocks into rwlocks
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This eliminates lock contention among IRQs as well as the need to
disable IRQs around idr_find, because there are no IRQ writers.

Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
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Joachim Fenkes authored and Roland Dreier committed Jul 10, 2007
1 parent 28db6be commit 26ed687
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Showing 6 changed files with 28 additions and 32 deletions.
4 changes: 2 additions & 2 deletions drivers/infiniband/hw/ehca/ehca_classes.h
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Original file line number Diff line number Diff line change
Expand Up @@ -293,8 +293,8 @@ void ehca_cleanup_av_cache(void);
int ehca_init_mrmw_cache(void);
void ehca_cleanup_mrmw_cache(void);

extern spinlock_t ehca_qp_idr_lock;
extern spinlock_t ehca_cq_idr_lock;
extern rwlock_t ehca_qp_idr_lock;
extern rwlock_t ehca_cq_idr_lock;
extern struct idr ehca_qp_idr;
extern struct idr ehca_cq_idr;

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12 changes: 6 additions & 6 deletions drivers/infiniband/hw/ehca/ehca_cq.c
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Original file line number Diff line number Diff line change
Expand Up @@ -163,9 +163,9 @@ struct ib_cq *ehca_create_cq(struct ib_device *device, int cqe, int comp_vector,
goto create_cq_exit1;
}

spin_lock_irqsave(&ehca_cq_idr_lock, flags);
write_lock_irqsave(&ehca_cq_idr_lock, flags);
ret = idr_get_new(&ehca_cq_idr, my_cq, &my_cq->token);
spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
write_unlock_irqrestore(&ehca_cq_idr_lock, flags);

} while (ret == -EAGAIN);

Expand Down Expand Up @@ -294,9 +294,9 @@ struct ib_cq *ehca_create_cq(struct ib_device *device, int cqe, int comp_vector,
"cq_num=%x h_ret=%lx", my_cq, my_cq->cq_number, h_ret);

create_cq_exit2:
spin_lock_irqsave(&ehca_cq_idr_lock, flags);
write_lock_irqsave(&ehca_cq_idr_lock, flags);
idr_remove(&ehca_cq_idr, my_cq->token);
spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
write_unlock_irqrestore(&ehca_cq_idr_lock, flags);

create_cq_exit1:
kmem_cache_free(cq_cache, my_cq);
Expand Down Expand Up @@ -334,9 +334,9 @@ int ehca_destroy_cq(struct ib_cq *cq)
* remove the CQ from the idr first to make sure
* no more interrupt tasklets will touch this CQ
*/
spin_lock_irqsave(&ehca_cq_idr_lock, flags);
write_lock_irqsave(&ehca_cq_idr_lock, flags);
idr_remove(&ehca_cq_idr, my_cq->token);
spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
write_unlock_irqrestore(&ehca_cq_idr_lock, flags);

/* now wait until all pending events have completed */
wait_event(my_cq->wait_completion, !atomic_read(&my_cq->nr_events));
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19 changes: 8 additions & 11 deletions drivers/infiniband/hw/ehca/ehca_irq.c
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Original file line number Diff line number Diff line change
Expand Up @@ -180,12 +180,11 @@ static void qp_event_callback(struct ehca_shca *shca,
{
struct ib_event event;
struct ehca_qp *qp;
unsigned long flags;
u32 token = EHCA_BMASK_GET(EQE_QP_TOKEN, eqe);

spin_lock_irqsave(&ehca_qp_idr_lock, flags);
read_lock(&ehca_qp_idr_lock);
qp = idr_find(&ehca_qp_idr, token);
spin_unlock_irqrestore(&ehca_qp_idr_lock, flags);
read_unlock(&ehca_qp_idr_lock);


if (!qp)
Expand All @@ -209,14 +208,13 @@ static void cq_event_callback(struct ehca_shca *shca,
u64 eqe)
{
struct ehca_cq *cq;
unsigned long flags;
u32 token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe);

spin_lock_irqsave(&ehca_cq_idr_lock, flags);
read_lock(&ehca_cq_idr_lock);
cq = idr_find(&ehca_cq_idr, token);
if (cq)
atomic_inc(&cq->nr_events);
spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
read_unlock(&ehca_cq_idr_lock);

if (!cq)
return;
Expand Down Expand Up @@ -411,19 +409,18 @@ static inline void process_eqe(struct ehca_shca *shca, struct ehca_eqe *eqe)
{
u64 eqe_value;
u32 token;
unsigned long flags;
struct ehca_cq *cq;

eqe_value = eqe->entry;
ehca_dbg(&shca->ib_device, "eqe_value=%lx", eqe_value);
if (EHCA_BMASK_GET(EQE_COMPLETION_EVENT, eqe_value)) {
ehca_dbg(&shca->ib_device, "Got completion event");
token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe_value);
spin_lock_irqsave(&ehca_cq_idr_lock, flags);
read_lock(&ehca_cq_idr_lock);
cq = idr_find(&ehca_cq_idr, token);
if (cq)
atomic_inc(&cq->nr_events);
spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
read_unlock(&ehca_cq_idr_lock);
if (cq == NULL) {
ehca_err(&shca->ib_device,
"Invalid eqe for non-existing cq token=%x",
Expand Down Expand Up @@ -480,11 +477,11 @@ void ehca_process_eq(struct ehca_shca *shca, int is_irq)
eqe_value = eqe_cache[eqe_cnt].eqe->entry;
if (EHCA_BMASK_GET(EQE_COMPLETION_EVENT, eqe_value)) {
token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe_value);
spin_lock(&ehca_cq_idr_lock);
read_lock(&ehca_cq_idr_lock);
eqe_cache[eqe_cnt].cq = idr_find(&ehca_cq_idr, token);
if (eqe_cache[eqe_cnt].cq)
atomic_inc(&eqe_cache[eqe_cnt].cq->nr_events);
spin_unlock(&ehca_cq_idr_lock);
read_unlock(&ehca_cq_idr_lock);
if (!eqe_cache[eqe_cnt].cq) {
ehca_err(&shca->ib_device,
"Invalid eqe for non-existing cq "
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4 changes: 2 additions & 2 deletions drivers/infiniband/hw/ehca/ehca_main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -96,8 +96,8 @@ MODULE_PARM_DESC(static_rate,
MODULE_PARM_DESC(scaling_code,
"set scaling code (0: disabled/default, 1: enabled)");

DEFINE_SPINLOCK(ehca_qp_idr_lock);
DEFINE_SPINLOCK(ehca_cq_idr_lock);
DEFINE_RWLOCK(ehca_qp_idr_lock);
DEFINE_RWLOCK(ehca_cq_idr_lock);
DEFINE_IDR(ehca_qp_idr);
DEFINE_IDR(ehca_cq_idr);

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12 changes: 6 additions & 6 deletions drivers/infiniband/hw/ehca/ehca_qp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -512,9 +512,9 @@ struct ehca_qp *internal_create_qp(struct ib_pd *pd,
goto create_qp_exit0;
}

spin_lock_irqsave(&ehca_qp_idr_lock, flags);
write_lock_irqsave(&ehca_qp_idr_lock, flags);
ret = idr_get_new(&ehca_qp_idr, my_qp, &my_qp->token);
spin_unlock_irqrestore(&ehca_qp_idr_lock, flags);
write_unlock_irqrestore(&ehca_qp_idr_lock, flags);

} while (ret == -EAGAIN);

Expand Down Expand Up @@ -733,9 +733,9 @@ struct ehca_qp *internal_create_qp(struct ib_pd *pd,
hipz_h_destroy_qp(shca->ipz_hca_handle, my_qp);

create_qp_exit1:
spin_lock_irqsave(&ehca_qp_idr_lock, flags);
write_lock_irqsave(&ehca_qp_idr_lock, flags);
idr_remove(&ehca_qp_idr, my_qp->token);
spin_unlock_irqrestore(&ehca_qp_idr_lock, flags);
write_unlock_irqrestore(&ehca_qp_idr_lock, flags);

create_qp_exit0:
kmem_cache_free(qp_cache, my_qp);
Expand Down Expand Up @@ -1706,9 +1706,9 @@ int internal_destroy_qp(struct ib_device *dev, struct ehca_qp *my_qp,
}
}

spin_lock_irqsave(&ehca_qp_idr_lock, flags);
write_lock_irqsave(&ehca_qp_idr_lock, flags);
idr_remove(&ehca_qp_idr, my_qp->token);
spin_unlock_irqrestore(&ehca_qp_idr_lock, flags);
write_unlock_irqrestore(&ehca_qp_idr_lock, flags);

h_ret = hipz_h_destroy_qp(shca->ipz_hca_handle, my_qp);
if (h_ret != H_SUCCESS) {
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9 changes: 4 additions & 5 deletions drivers/infiniband/hw/ehca/ehca_uverbs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -253,17 +253,16 @@ int ehca_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
u32 rsrc_type = (fileoffset >> 24) & 0xF; /* sq,rq,cmnd_window */
u32 cur_pid = current->tgid;
u32 ret;
unsigned long flags;
struct ehca_cq *cq;
struct ehca_qp *qp;
struct ehca_pd *pd;
struct ib_uobject *uobject;

switch (q_type) {
case 1: /* CQ */
spin_lock_irqsave(&ehca_cq_idr_lock, flags);
read_lock(&ehca_cq_idr_lock);
cq = idr_find(&ehca_cq_idr, idr_handle);
spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
read_unlock(&ehca_cq_idr_lock);

/* make sure this mmap really belongs to the authorized user */
if (!cq)
Expand All @@ -289,9 +288,9 @@ int ehca_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
break;

case 2: /* QP */
spin_lock_irqsave(&ehca_qp_idr_lock, flags);
read_lock(&ehca_qp_idr_lock);
qp = idr_find(&ehca_qp_idr, idr_handle);
spin_unlock_irqrestore(&ehca_qp_idr_lock, flags);
read_unlock(&ehca_qp_idr_lock);

/* make sure this mmap really belongs to the authorized user */
if (!qp)
Expand Down

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