* [PATCH] scsi: libfc: Use refcount_* APIs for reference count management
@ 2022-12-20 4:30 Deepak R Varma
2022-12-28 10:18 ` Deepak R Varma
0 siblings, 1 reply; 2+ messages in thread
From: Deepak R Varma @ 2022-12-20 4:30 UTC (permalink / raw)
To: Hannes Reinecke, James E.J. Bottomley, Martin K. Petersen,
linux-scsi, linux-kernel
Cc: Saurabh Singh Sengar, Praveen Kumar, drv
The atomic_t API based object reference counter management is prone to
counter value overflows, object use-after-free issues and to return
puzzling values. The improved refcount_t APIs are designed to address
these known issues with atomic_t reference counter management. This
white paper [1] has detailed reasons for moving from atomic_t to
refcount_t APIs. Hence replace the atomic_* based implementation by its
refcount_* based equivalent.
The issue is identified using atomic_as_refcounter.cocci Coccinelle
semantic patch script.
[1] https://arxiv.org/pdf/1710.06175.pdf
Signed-off-by: Deepak R Varma <drv@mailo.com>
---
Note: The proposal is compile tested only.
drivers/scsi/libfc/fc_exch.c | 10 +++++-----
include/scsi/libfc.h | 2 +-
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index 1d91c457527f..1c49fddb65e3 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -246,7 +246,7 @@ static const char *fc_exch_rctl_name(unsigned int op)
*/
static inline void fc_exch_hold(struct fc_exch *ep)
{
- atomic_inc(&ep->ex_refcnt);
+ refcount_inc(&ep->ex_refcnt);
}
/**
@@ -312,7 +312,7 @@ static void fc_exch_release(struct fc_exch *ep)
{
struct fc_exch_mgr *mp;
- if (atomic_dec_and_test(&ep->ex_refcnt)) {
+ if (refcount_dec_and_test(&ep->ex_refcnt)) {
mp = ep->em;
if (ep->destructor)
ep->destructor(&ep->seq, ep->arg);
@@ -329,7 +329,7 @@ static inline void fc_exch_timer_cancel(struct fc_exch *ep)
{
if (cancel_delayed_work(&ep->timeout_work)) {
FC_EXCH_DBG(ep, "Exchange timer canceled\n");
- atomic_dec(&ep->ex_refcnt); /* drop hold for timer */
+ refcount_dec(&ep->ex_refcnt); /* drop hold for timer */
}
}
@@ -1897,7 +1897,7 @@ static void fc_exch_reset(struct fc_exch *ep)
ep->state |= FC_EX_RST_CLEANUP;
fc_exch_timer_cancel(ep);
if (ep->esb_stat & ESB_ST_REC_QUAL)
- atomic_dec(&ep->ex_refcnt); /* drop hold for rec_qual */
+ refcount_dec(&ep->ex_refcnt); /* drop hold for rec_qual */
ep->esb_stat &= ~ESB_ST_REC_QUAL;
sp = &ep->seq;
rc = fc_exch_done_locked(ep);
@@ -2332,7 +2332,7 @@ static void fc_exch_els_rrq(struct fc_frame *fp)
*/
if (ep->esb_stat & ESB_ST_REC_QUAL) {
ep->esb_stat &= ~ESB_ST_REC_QUAL;
- atomic_dec(&ep->ex_refcnt); /* drop hold for rec qual */
+ refcount_dec(&ep->ex_refcnt); /* drop hold for rec qual */
}
if (ep->esb_stat & ESB_ST_COMPLETE)
fc_exch_timer_cancel(ep);
diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h
index 6e29e1719db1..ce65149b300c 100644
--- a/include/scsi/libfc.h
+++ b/include/scsi/libfc.h
@@ -432,7 +432,7 @@ struct fc_seq {
*/
struct fc_exch {
spinlock_t ex_lock;
- atomic_t ex_refcnt;
+ refcount_t ex_refcnt;
enum fc_class class;
struct fc_exch_mgr *em;
struct fc_exch_pool *pool;
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] scsi: libfc: Use refcount_* APIs for reference count management
2022-12-20 4:30 [PATCH] scsi: libfc: Use refcount_* APIs for reference count management Deepak R Varma
@ 2022-12-28 10:18 ` Deepak R Varma
0 siblings, 0 replies; 2+ messages in thread
From: Deepak R Varma @ 2022-12-28 10:18 UTC (permalink / raw)
To: Hannes Reinecke, James E.J. Bottomley, Martin K. Petersen,
linux-scsi, linux-kernel
Cc: Saurabh Singh Sengar, Praveen Kumar, Deepak R Varma
On Tue, Dec 20, 2022 at 10:00:45AM +0530, Deepak R Varma wrote:
> The atomic_t API based object reference counter management is prone to
> counter value overflows, object use-after-free issues and to return
> puzzling values. The improved refcount_t APIs are designed to address
> these known issues with atomic_t reference counter management. This
> white paper [1] has detailed reasons for moving from atomic_t to
> refcount_t APIs. Hence replace the atomic_* based implementation by its
> refcount_* based equivalent.
> The issue is identified using atomic_as_refcounter.cocci Coccinelle
> semantic patch script.
>
> [1] https://arxiv.org/pdf/1710.06175.pdf
>
> Signed-off-by: Deepak R Varma <drv@mailo.com>
Hello,
May I please request a review and feedback on this patch proposal?
Thank you,
./drv
> ---
> Note: The proposal is compile tested only.
>
> drivers/scsi/libfc/fc_exch.c | 10 +++++-----
> include/scsi/libfc.h | 2 +-
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
> index 1d91c457527f..1c49fddb65e3 100644
> --- a/drivers/scsi/libfc/fc_exch.c
> +++ b/drivers/scsi/libfc/fc_exch.c
> @@ -246,7 +246,7 @@ static const char *fc_exch_rctl_name(unsigned int op)
> */
> static inline void fc_exch_hold(struct fc_exch *ep)
> {
> - atomic_inc(&ep->ex_refcnt);
> + refcount_inc(&ep->ex_refcnt);
> }
>
> /**
> @@ -312,7 +312,7 @@ static void fc_exch_release(struct fc_exch *ep)
> {
> struct fc_exch_mgr *mp;
>
> - if (atomic_dec_and_test(&ep->ex_refcnt)) {
> + if (refcount_dec_and_test(&ep->ex_refcnt)) {
> mp = ep->em;
> if (ep->destructor)
> ep->destructor(&ep->seq, ep->arg);
> @@ -329,7 +329,7 @@ static inline void fc_exch_timer_cancel(struct fc_exch *ep)
> {
> if (cancel_delayed_work(&ep->timeout_work)) {
> FC_EXCH_DBG(ep, "Exchange timer canceled\n");
> - atomic_dec(&ep->ex_refcnt); /* drop hold for timer */
> + refcount_dec(&ep->ex_refcnt); /* drop hold for timer */
> }
> }
>
> @@ -1897,7 +1897,7 @@ static void fc_exch_reset(struct fc_exch *ep)
> ep->state |= FC_EX_RST_CLEANUP;
> fc_exch_timer_cancel(ep);
> if (ep->esb_stat & ESB_ST_REC_QUAL)
> - atomic_dec(&ep->ex_refcnt); /* drop hold for rec_qual */
> + refcount_dec(&ep->ex_refcnt); /* drop hold for rec_qual */
> ep->esb_stat &= ~ESB_ST_REC_QUAL;
> sp = &ep->seq;
> rc = fc_exch_done_locked(ep);
> @@ -2332,7 +2332,7 @@ static void fc_exch_els_rrq(struct fc_frame *fp)
> */
> if (ep->esb_stat & ESB_ST_REC_QUAL) {
> ep->esb_stat &= ~ESB_ST_REC_QUAL;
> - atomic_dec(&ep->ex_refcnt); /* drop hold for rec qual */
> + refcount_dec(&ep->ex_refcnt); /* drop hold for rec qual */
> }
> if (ep->esb_stat & ESB_ST_COMPLETE)
> fc_exch_timer_cancel(ep);
> diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h
> index 6e29e1719db1..ce65149b300c 100644
> --- a/include/scsi/libfc.h
> +++ b/include/scsi/libfc.h
> @@ -432,7 +432,7 @@ struct fc_seq {
> */
> struct fc_exch {
> spinlock_t ex_lock;
> - atomic_t ex_refcnt;
> + refcount_t ex_refcnt;
> enum fc_class class;
> struct fc_exch_mgr *em;
> struct fc_exch_pool *pool;
> --
> 2.34.1
>
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